WO2005001568A1 - Photographic elements containing a de-aggregating compound, dye-forming coupler, stabilizer and solvent - Google Patents

Abstract

The present invention relates to a photographic element comprising at least one light-sensitive silver halide emulsion layer having associated therewith in the same dispersion at least one de-aggregating compound of formula (I), at least one heterocyclic magenta dye-forming coupler of formula (II), at least one stabilizer of formula (III) and at least one compound of formula (IV), wherein said formulae (I)-(IV) are defined in the specification. The invention provides enhanced image stabilization, and a narrowing of the spectral bandwidths normally associated with the use of bicyclic or tricyclic compounds.

Description

PHOTOGRAPHIC ELEMENTS CONTAINING A DE- AGGREGATING COMPOUND, DYE-FORMING COUPLER, STABILIZER AND SOLVENT

FIELD OF THE INVENTION This invention relates to a silver halide colour photographic material, and more particularly to a silver halide colour photographic material with improved light stability, colour reproducibility and dye hue.

BACKGROUND OF THE INVENTION In any chromogenic photographic material it is desirable that the dyes formed should be bright in colour, absorbing light in the appropriate spectral region, with very little secondary absorption so that good colour reproducibility is obtained. It is also important that the formed photographic images should be resistant to fading due to heat, humidity and light. Many of the desired hue characteristics are achieved by changing the molecular structure of the photographic dye-forming coupler, hereinafter coupler. For example alkyl substituents on a pyrazoloazole nucleus will form magenta dyes on photographic development. In addition, adjusting the environment of the coupler can influence the dye hue of the azomethine dye that is formed during photographic processing. For example, the spectral properties of the dyes can be altered using hue-shifting solvents such as sulfonamides (EP-A-0 309 159, EP-A-0264 083), carbonamides (e.g. US Patent Nos. 4,935,321 and 5,258,278), aryl ureas (US Patent No. 4,808,502), ballasted and substituted phenols (US Patent No. 4,562,146, DE 3,936,300) and sulfones and sulfoxides (US Patent No 5,232,821). Phosphate esters are disclosed as a high-boiling solvent in

EP-A-0 515 128 in combination with two types of magenta coupler. US Patent No. 5,378,595 discloses the use of phosphate esters for improving dark stability. US Patent No. 5,104,781 discloses the use of phosphate esters in combination with a magenta coupler and a piperidinyl stabilizer. For economic and environmental reasons a reduction in the quantities of materials used in photographic materials is desirable. Couplers derived from bicyclic or even tricyclic heterocyclic compounds are increasingly being utilised because they can form dyes with higher absorptivities than those that have been used for many years. Thus, on an equimolar basis, these heterocyclic couplers can provide much higher dye densities from the same amounts of silver, so that it is possible to generate the same dye densities from lower laydowns of silver and coupler. However, heterocyclic couplers based on a pyrazole ring, such as pyrazolotriazole and pyrazolobenzimidazole couplers, that are increasingly being used in photographic elements, form magenta dyes which are highly aggregated, ^• that is they form a self-associating assembly of monomeric molecules. US Patent No. 5,294,528 lists a variety of agents which can be used to break the aggregation of an azomethine dye (more correctly an azamethine dye), in particular the dye from magenta pyrazolotriazole couplers. It is claimed in this patent that "azomelnine dyes formed from pyrazoloazole couplers are liable to aggregate, and the higher the aggregation degree of the dyes is, the lower the light-fastness is, and that by breaking the aggregation the light-fastness of azomethine dyes can be enhanced". Whilst it is true that some magenta pyrazoloazole couplers with bulky substituents provide dyes which are less aggregated and have better light stability than those with less bulky substituents, de-aggregation is not the main cause of improved light stability. A de-aggregating compound is understood to act by intervention within the dispersed oil phase containing the aggregated dye and is necessarily a component of the coupler dispersion. Compounds which de-aggregate in this way may perform quite different functions if included in separate dispersions, e.g. as UN absorbers. We have found that de-aggregating compounds do not necessarily provide extra light stability unless another appropriate light stabilizer is present.

Thus improved light stability is not correlated with de-aggregation. Methods to improve dye stability involve using compounds such as, for example, spiroindanes (US Patent No. 5,212,055), bisphenols (US Patent No. 3,700,455), thiomorpholine dioxide materials (US Patent Nos. 5,491,054 and 5,484,696), metal complexes (DE 3605279) or combinations of these including antioxidants (EP-A-0203 746). All of these, even when including the use of high levels of solvent to help de-aggregate the dye, contribute to very small improvements in dye stability, with often little or no improvement in colour quality. Another way of improving dye stability is to utilise UN absorbers, usually in a separate UN filtration layer, although it is sometimes beneficial to combine the UN absorbers in the same layer as the coupler. One group of

UN absorbers usually used in a separate layer are the 2-hydroxyphenyltriazines as described in DE 2113833 and DE 2230304. 2-hydroxyphenyltriazine materials in conjunction with magenta or yellow couplers to improve dye stability and D_mm yellowing have been disclosed in DE 4444258 and US Patent No. 5,541,045 respectively. PROBLEM TO BE SOLVED BY THE INVENTION The dyes formed from heterocyclic couplers based on a pyrazole ring structure, such as pyrazolotriazoles and pyrazolobenzimidazoles, are highly aggregated. The main spectral absorptions of these dyes are due to the monomeric species, but the secondary absorptions caused by the presence of aggregated dye have a deleterious effect on the quality of the image produced, so that the colours of a scene are represented less accurately than desired. Hue-shifting by solvents alone is of little use so that a compound that will de-aggregate the dyes formed is also required. Such de-aggregating compounds which can provide photographic materials with an increased colour gamut do not necessarily, however, provide sufficient stability of the magenta image. There is therefore a need to find a combination of compounds which maintains de-aggregation and additionally provides such stabilization. SUMMARY OF THE INVENTION It has now been found that, when a particular type of N-containing heterocyclic compound is combined in the same dispersion in a photographic element with a magenta coupler based on a pyrazole ring, a certain type of dye stabilizer and a phosphorus (V) oxide compound, it unexpectedly de-aggregates the dyes formed, reducing the unwanted absorptions in the spectra of the azomethine dyes and improving colour reproduction, whilst colourfastness to light is improved. Thus according to the present invention there is provided a photographic element comprising at least one light-sensitive silver halide emulsion layer having associated therewith in the same dispersion at least one de-aggregating compound of formula (I), at least one heterocyclic magenta dye- forming coupler of formula (II), at least one stabilizer of formula (HI) and at least one compound of formula (IN), wherein the de-aggregating compound has the formula (I)

(D wherein Zi to Z₅ are independently selected from the class consisting of nitrogen atoms or unsubstituted or substituted carbon atoms, provided that (a) at least two of Zi to Z₅ are unsubstituted or substituted carbon atoms and (b) no more than two of Zi to Z₅ are carbon atoms substituted with a substituted alkoxy group; the heterocyclic magenta dye-foiniing coupler has the formula (II):-

(II) wherein R¹ is an electron-donating substituent; R° is a substituent; and q is 0 to 4; Z^a represents the atoms necessary to complete an unsubstituted or substituted 5- to 10-membered heterocyclic ring or ring system which may contain one or more other heteroatoms selected from nitrogen, oxygen and sulfur; providing that each R^c is attached to a carbon atom of the ring; and X is selected from the class consisting of hydrogen or halogen or a group which is separable by the reaction of coupler with an oxidized colour developing agent; the stabilizer of formula (HI) has the formula

(in) wherein R₅ is selected from the class consisting of an unsubstituted or substituted alkyl, aryl, acyl, alkoxycarbonyl, aryloxycarbonyl, alkyl- or aryl- amido group; each Rg is an independently selected substituent; or either R₅ and one R_δ substituent, or two R₆ substituents, may join to form an unsubstituted or substituted 5- to 10-membered ring or ring system which may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur; and s is 0 to 4; provided that at least one of R₅ and a Re substituent contains a ballast group comprising at least 8 carbon atoms; and Z represents the atoms necessary to complete an unsubstituted or substituted 5- to 7-membered heterocyclic ring or ring system which may contain one or more other heteroatoms selected from nitrogen, oxygen and sulfur; the compound of formula (IN) has the structure

(IN) wherein R₈, R₉ and R₁₀ are independently selected from the class consisting of an unsubstituted or substituted alkyl, aryl, heterocyclyl, hetrocyclyloxy, alkoxy or aryloxy group or two of R₈,R and R₁₀ may join to form a 5- or 6-membered ring, which may be substituted, provided that the sum of the number of carbon atoms of R₈, R₉ and R₁₀ is at least 12.

In another embodiment of the invention there is provided a multi- colour photographic element comprising a support bearing yellow, magenta and cyan image-dye-forming units comprising at least one blue-, green- or red- sensitive silver halide emulsion layer having associated therewith at least one yellow, magenta or cyan dye-forming coupler respectively, wherein the element is as herein described. In yet another embodiment of the invention there is provided a process of forming an image in a photographic element as hereinbefore defined after the element has been imagewise exposed to light, comprising contacting the element, as herein described, with a colour developing agent. ADVANTAGEOUS EFFECT OF THE INVENTION This invention allows for an improvement in the colour quality and stability of photographic materials which have in, at least one layer, a bicyclic or tricyclic coupler incorporating a pyrazole moiety as one of the heterocyclic rings. Not only are the spectral bandwidths narrowed significantly by the use of de-aggregating heterocyclic compounds, thus reducing unwanted absorptions, but also an enhanced image stabilization is obtained by the use of a specified stabilizer and a specified phosphorus (V) oxide compound, compared with that which can be achieved in the absence of the combination of compounds for use in the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a series of normalised spectra obtained from exposed and processed coatings of coupler M-2 with different solvent and components of the invention. Curve A, represents M-2 in comparative solvent D. Curve B, represents M-2 with comparative solvent D, stabilizer ST-1 and triazine compound 1-1. Curve C, represents M-2 with solvent P-l and stabilizer ST-1. Curve D, represents M-2 with all the materials for use in the invention: solvent P- 1 , stabilizer ST-1 and triazine I- 1. Curve E, represents M-2 with solvent P-l, stabilizer ST-1 and triazine 1-33.

DETAILED DESCRIPTION OF THE INVENTION The invention is described as in the Summary of the Invention and relates to the de-aggregation of dyes derived from certain heterocyclic couplers to provide a more accurate rendition of hues in photographic materials and enhanced image stabilization. As used herein and throughout the specification unless where specifically stated otherwise, the term "alkyl" refers to a saturated or unsaturated, straight or branched chain alkyl group including alkenyl and aralkyl, and includes cyclic groups, including cycloalkenyl, having 3-8 carbon atoms. The term "aryl" includes fused aryl. The de-aggregating compound of formula (I) may be, for example a pyridine, a pyrimidine, a 1,3,5 triazine, a 1,2,4 triazine or a tetrazine, but preferably it comprises a 1,3,5-triazine, pyrimidine or pyridine nucleus having the formula (IA)

(IA) wherein Ri, R₂ and R₃ are independently hydrogen or a substituent; and Z and Z are independently selected from the class consisting of nitrogen atoms or unsubstituted or substituted carbon atoms, provided that no more than two of Ri to R₃ are carbon atoms substituted with a substituted alkoxy group. More preferably however Z₂ and Z₄ are both nitrogen atoms such that the de-aggregating compound comprises a triazine nucleus of formula (IB)

(IB) wherein R_ls R₂ and R₃ are as defined for compound of formula (IA). In formula (IA) or (IB), R_l5 R₂ and R₃ are preferably independently selected from the class consisting of an unsubstituted or substituted alkyl, aryl, alkyl- or aryl-amino, alkyl- or aryl-thio, alkoxy, aryloxy, alkyl- or aryl-carbamoyl, alkyl- or aryl-sulfamoyl, naphthyl or a heterocyclic ring or ring system, such as, for example, a pyridyl, benzimidazolyl, thienyl, morpholino, imidazolyl, pyridazolyl, quinolinyl or pyridone. Substituents on Ri,R₂ and R₃ are independently selected from hydroxy, cyano, fluoro, chloro, bromo, iodo; or an unsubstituted or substituted alkyl, aryl, heterocyclyl, alkoxy, aryloxy, alkyl- or aryl-carbonyl, alkyl- or aryl- oxycarbonyl, acyloxy, carbonamido, alkyl- or aryl-carbonamido, alkyl- or aryl- oxycarbonylamino, alkyl- or aryl-sulfonyl, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or aryl-sulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl- sulfamoylamino, alkyl- or aryl-sulfonamido, alkyl- or aryl-thio, alkyl- or aryl phosphonate, nitro, alkyl- or aryl-amino, alkyl- or aryl-ureido or alkyl- or aryl- carbamoyl group, any of which may be further substituted, for example with one or more other such substituents. For example when one or two of the above groups is an alkoxy group it may suitably be substituted with, for example, one or more hydroxy and/or alkoxy groups, which may in turn be further substituted. An alkyl group may typically be substituted by halogen, or by a hydroxy, alkoxy, carbonamido or an alkoxycarbonyl group. Ri, R and R₃ are more preferably independently an unsubstituted or substituted alkyl group or a phenyl group, optionally substituted, for example with one or more hydroxy, halogen, alkoxy, alkyl, alkylsulfonamido or alkyl- sulfonyl groups, more preferably in the ortho and/or para positions, and these groups may be further substituted. More preferably at least two and especially all of Ri, R₂ and R₃ are phenyl groups.

The following examples fiirther illustrate de-aggregating compounds of formula (I) that can be used in the invention, but the invention is not to be considered as limited to these compounds.

According to the invention at least one compound of formula (I) is combined with at least one heterocyclic magenta dye-forming coupler of formula (H) having the structure:

(II) wherein R¹ is an electron-donating substituent; R^c is a substituent; q is 0 to 4; Z^a represents the atoms necessary to complete an unsubstituted or substituted 5- to 10-membered heterocyclic ring or ring system which may contain one or more other heteroatoms selected from nitrogen, oxygen and sulfur, providing that each R^c is attached to a carbon atom of the ring; and X is selected from the class consisting of hydrogen or halogen or a group which is separable by the reaction of coupler with an oxidized colour developing agent.

One embodiment of a compound of formula (II) has the formula (HA.)

(IIA)

wherein R¹ and X are as defined for formula (II); Z and Z are independently selected from the class consisting of -CH- groups, which may together form part of an unsubstituted or substituted phenyl ring, -CR- groups, wherein R is a substituent, or nitrogen atoms. Structures falling within formula (IIA) may, for example, be one of the following: -

(a) (b)

(c) (d) wherein R¹ and X are as defined for formula (II); each of R² to R⁴ is hydrogen or an independently selected substituent; and r is 0 to 4. R¹ is preferably selected from the class consisting of an alkyl, aryl, alkoxy, aryloxy, acyloxy, alkyl- or aryl-thio, alkyl- or aryl-amino, alkyl- or aryl carbonamido or an alkyl- or aryl-ureido, any of which may be substituted, for example with an alkyl, alkoxy, arylsulfonyl or alkylcarbonamido group, any of which may be further substituted. More preferably R¹ is an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy, acyloxy or alkylcarbonamido group, most preferably a tertiary alkyl group, especially a t-butyl group. R and R are preferably independently selected from the class consisting of an unsubstituted or substituted alkyl, aryl, alkyl-or aryl-thio, alkyl- or aryl-amino or an alkyl- or aryl-carbonamido group, more preferably a phenyl group. Substituents on R and R may be independently selected from, fluoro, chloro, bromo, iodo, hydroxy; or an unsubstituted or substituted alkyl, aryl, heterocyclyl, alkoxy, aryloxy, alkyl- or aryl-oxycarbonyl, acyloxy, carbonamido, alkyl- or aryl-carbonamido, alkyl- or aryl- carbamate, alkyl- or aryl-oxycarbonyl- a ino, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or aryl- sulf-tmoyl-imino, alkyl- or aryl-sulfonamido, alkyl- or aryl-thio, alkyl- or aryl- amino or an alkyl- or aryl-ureido group, any of which may be further substituted, for example with one or more other such substituents. Most preferably one of R and R is a phenyl group optionally substituted for example, with one or more halogen, alkyl, alkoxy, alkoxy- carbonyl, alkyl- or aryl-sulfonamido, alkyl- or aryl- carbonamido, alkyl- or aryl- carbamate or alkyl- or aryl- ureido groups, any of which may be further substituted. Alternatively R² and R³ may join to form an unsubstituted or substituted phenyl ring. Each R⁴ may be independently, for example, a halogen or an unsubstituted or substituted alkyl or an alkyl- or aryl-carbonamido group.

Substituents on R⁴ may be those as defined for R² and R³ but may also be a cyano or an unsubstituted or substituted alkyl- or aryl-carbonyl, alkyl- or aryl-sulfonyl, alkyl- or aryl-sulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl- phosphonate, nitro or alkyl- or aryl-carbamoyl, which may be further substituted, for example with one or more other such substituents. X is hydrogen or a coupling-off group, suitably a halogen atom or a group linked by an atom of sulfur, oxygen or nitrogen, such as an unsubstituted or substituted alkoxy, aryloxy, arylthio, azolyl, substituted mercaptotetrazole or thiopropionic acid. Chlorine atoms are conveniently employed. The presence or absence of such groups determines the chemical equivalency of the coupler, i.e. whether it is a 2-equivalent or 4-equivalent coupler, and its particular identity can modify the reactivity of the coupler. Such groups can advantageously affect the layer in which the coupler is coated, or other layers in the photographic recording material, by performing, after release from the coupler, functions such as dye formation, dye hue adjustment, development acceleration or inhibition, bleach acceleration or inhibition, electron transfer facilitation and colour correction. Representative classes of such coupling-off groups include, for example, halogen, alkoxy, aryloxy, heterocyclyloxy, sulfonyloxy, acyloxy, acyl, heterocyclyl, sulfonamido, heterocyclylthio, benzothiazolyl, phosophonyloxy, alkylthio, arylthio and arylazo. These coupling-off groups are described in the art, for example, in U.S. Patent Nos. 2,455,169, 3,227,551, 3,432,521, 3,467,563, 3,617,291, 3,880,661, 4,052,212 and 4,134,766; and in UK Patent Nos. and published applications 1,466,728, 1,531,927, 1,533,039, 2,066,755A and 2,017,704A, the disclosures of which are incorporated herein by reference. Halogen, alkoxy and aryloxy groups are most suitable. Examples of suitable coupling-off groups are -Cl, -F, -Br, -SCN, -OCH₃, -OC₆H₅, -OCH₂C(=O)NHCH₂CH₂OH, -OCH₂C(O)NHCH₂CH₂OCH₃, -OCH₂C(O)NHCH₂CH₂OC(=O)OCH₃, -P(=O)(OC₂H₅)2, -SCH2CH2COOH,

Typically the coupling-off group is a chlorine atom, hydrogen or a p-methoxy- phenoxy group. The following examples further illustrate heterocyclic magenta dye- forming couplers that may be used in the invention. It is not to be construed that the present invention is limited to these examples.

M-l

M-2

M-3

M-4

M-5

M-6

M-7

M-8

M-9

M-10

M-ll

M-12

HCONHC₁₈H₃₇n

M-13

M-14

M-15

M-16

M-17

M-18

M-19

M-20

M-21

M-22

M-23

M-24

M-25

M-26

M-27

M-28

M-29

M-30

M-31

The stabilizer has the formula (El):

(IH) wherein R₅ is selected from the class consisting of an unsubstituted or substituted alkyl, aryl, acyl, alkoxycarbonyl, aryloxycarbonyl, alkyl- or aryl- amido group; each Rβ is an independently selected substituent; or either R₅ and one Rδ substituent, or two Re substituents, may join to form an unsubstituted or substituted 5- to 10-membered ring or ring system which may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur; and s is 0 to 4; provided that at least one of R₅ and a Re substituent contains a ballast group comprising at least 8 carbon atoms; and Zb represents the atoms necessary to complete an unsubstituted or substituted 5- to 7-membered heterocyclic ring system which may contain one or more other heteroatoms selected from nitrogen, oxygen and sulfur. In a preferred embodiment, R₅ is an alkyl or aryl group, optionally substituted, for example, with an alkyl, hydroxy, alkoxy, aryloxy, acyl, acyloxy or alkoxycarbonyl group and these groups may in turn be substituted, for example with the same or similar groups. Each Re, when present, is preferably independently a cyano, fluoro, chloro, bromo, iodo; or an unsubstituted or substituted alkyl, aryl, heterocyclyl, alkoxy, aryloxy, alkyl- or aryl-carbonyl, alkyl- or aryl-oxycarbonyl, acyloxy, carbonamido, alkyl- or aryl-carbonamido, alkyl- or aryl-oxycarbonylamino, alkyl- or aryl-sulfonyl, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or aryl-sulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl-sulfamoylamino, alkyl- or aryl-sulfonamido, alkyl- or aryl-thio, alkyl- or aryl-phosphonate, nitro, alkyl- or aryl-amino, alkyl- or aryl-ureido or alkyl- or aryl-carbamoyl group, any of which may be further substituted, for example with one or more other such substituents. Preferably s is 0, 1 or 2. When s is other than 0, R is more preferably, for example, one or more halogen atoms or an alkyl, especially a secondary or tertiary alkyl, alkylsulfonamido or alkoxy group. Alternatively either R₅ and one Re substituent, or two R substituents, may join to form an unsubstituted or substituted 5- to 10-membered ring or ring system which may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur. For example two Rό groups may join to form a benzene ring fused to the phenyl ring to give a naphthalene or R₅ and Re may join to form a pyran ring to give a chroman, which may be substituted. Preferably OR₅ is in the para position with relation to the nitrogen-containing group . Z represents the atoms necessary to form a ring system which may contain no other heteroatoms or which may include one or more other heteroatoms forming, for example a morpholino or thiomorpholine dioxide (wherein the N and SO₂ groups may be adjacent or separated by methylene groups). In a particularly preferred embodiment the stabilizer of formula (HI) has the formula (E-IA)

wherein R₅, Re and s are as defined above for formula (ID) and R is selected from a methylene group, O or SO_2> and is most preferably SO₂. The following examples further illustrate stabilizers that may be used in the invention. It is not to be construed that the present invention is limited to these examples.

ST-15

It is important that the substituent groups R_\ to R₃, R¹ to R⁴, R₅ and Re, R^c and X of the de-aggregating compound, coupler and stabilizer are selected so as to adequately ballast the coupler and the resulting dye in the organic solvent in which the coupler is dispersed and also to ballast the stabilizer. The ballasting may be accomplished by providing hydrophobic substituent groups in one or more of these substituent groups. Generally a ballast group is an organic radical of such size and configuration as to confer on the coupler and stabilizer molecules sufficient bulk and aqueous insolubility as to render them substantially nondiffusible from the layer in which they are coated in a photographic element. Thus the combination of these substituent groups in the couplers and stabilizers for use in the invention are suitably chosen to meet these criteria. To be effective -the ballast will usually contain at least 8 carbon atoms and typically contains 10 to 30 carbon atoms. Suitable ballasting may also be accomplished by providing a plurality of groups which in combination meet these criteria. Furthermore, even if the coupling-off group X in the coupler contains a ballast it is often necessary to ballast the other substituents as well, since X is eliminated from the molecule upon coupling. The compound of formula (IV) has the structure O R₁₀ P Rs R_β wherein R₈, R₉ and R₁₀ are independently selected from the class consisting of an unsubstituted or substituted alkyl, aryl, heterocyclyl, heterocyclyloxy, alkoxy or aryloxy group or two of R_8j R and R₁₀ may join to form a 5- or 6- remembered ring, which may be substituted, provided that the sum of the number of carbon atoms is at least 12. Suitable substituents on R₈,R and R₁₀ include, for example, one or more halogen, alkyl, alkoxycarbonyl, acyloxy, alkylcarbamoyl, alkylsulfamoyl and acyl groups. The compound of formula (IV) may comprise two phosphorus(N) oxide groupings wherein one of groups R₈ , R₉ and R₁₀ is a common linking group. For example, the two phosphorus atoms may be joined by a O-phenyl-O group or a phenyl group. Preferably each of R₈, R and Rio is an unsubstituted or substituted alkyl, alkoxy or aryloxy group and more preferably each of R₈, R and Rι₀ is the same. The following examples further illustrate compounds of formula (IV) that may be used in the invention. It is not to be construed that the present invention is hmited to these examples.

o II ^8 -"^■17 ^— ^8 "17 ^C8^H17 P-5

15

O C₈H— P-O-C₈H₁₇ C₀ H,-, P-7

CH O 3\ II , C₁₂H₂₅ O-P-O O CH' P-8

p_9

15

20

O C₂H₅— O-^-CH₂CH₂COOC₁₄H₂₉ O C₂H₅ P-15

O C₆H₁₃— O-P-CH₂CH₂OCOC₈H₁₇ O I

10 ^C6^H13 P-16

15 °l C₄H— O-P-(CH₂)₁₀CON(C₂H₅). ? C₄H₉ P-18

P-28

Unless otherwise specifically stated, substituent groups which may be substituted on molecules herein include any groups, whether substituted or unsubstituted, which do not destroy properties necessary for photographic utility. When the term "group" is applied to the identification of a substituent containing a substitutable hydrogen, it is intended to encompass not only the substituent's unsubstituted form, but also its form further substituted with any group or groups as herein mentioned. Suitably, the group may be halogen or may be bonded to the remainder of the molecule by an atom of carbon, silicon, oxygen, nitrogen, phosphorous or sulfur. The substituent may be, for example, halogen, such as chlorine, bromine or fluorine; nitro; hydroxyl; cyano; carboxyl; or groups which may be further substituted, such as alkyl, including straight or branched chain alkyl, such as methyl, trifluoromethyl, ethyl, t-butyl, 3-(2,4-di-t-pentylphenoxy) propyl and tetradecyl; alkenyl, such as ethylene, 2-butene; alkoxy, such as methoxy, ethoxy, propoxy, butoxy, 2-methoxyethoxy, sec÷butoxy, hexyloxy, 2-ethylhexyloxy, tetradecyloxy, 2-(2,4-di-t-pentylphenoxy)ethoxy and 2-dodecyl- oxyethoxy; aryl such as phenyl, 4-t-butyl-phenyl, 2,4,6-trimethylphenyl, naphthyl; aryloxy, such as phenoxy, 2-methylphenoxy, alpha- or beta-naphthyloxy and 4-tolyloxy; carbonamido, such as acetamido, benzamido, butyramido, tetradecanamido, alpha-(2,4-di-t-pentylphenoxy)acetamido, alpha-(2,4-di-t-pentyl- phenoxy)butyramido, alpha-(3-pentadecylphenoxy)hexanamido, alpha-

(4-hydroxy-3-t-butylphenoxy)tetradecanamido, 2-oxopyrrolidin-l-yl, 2-oxo- 5-tetradecylpyrrolin-l-yl, N-methyltetradecanamido, N-succinimido, N-phthalimido, 2,5-dioxo-l-oxazolidinyl, 3-dodecyl-2,5-dioxo-l-imidazolyl and N-acetyl-N-dodecylamino, ethoxycarbonylamino, phenoxycarbonylamino, benzyloxycarbonylammo, hexadecyloxycarbonylammo, 2,4-di-t-butylphenoxy- carbonylamino, phenylcarbonylamino, 2,5-(di-t-pentylphenyl)carbonylamino, ?-dodecylphenylcarbonylamino, -toluylcarbonylamino, N-methylureido, N,N-dimethylureido, N-methyl-N-dodecylureido, N-hexadecylureido, N,N-dioctadecylureido, N,N-dioctyl-N'-ethylureido, N-phenylureido, N,N-di- phenylureido, N-phenyl-N-j->-toluylureido, N-(m-hexadecylphenyl)ureido,

N,N-(2,5-di-t-pentylphenyl)-N'-ethylureido and t-butylcarbonamido; sulfonamido, such as methylsulfonamido, benzenesulfonamido, >-toluylsulfonamido, -dodecylbenzenesulfonamido, N-memyltetradecylsulfonarnido, N,N-dipropyl- sulfamoylamino and hexadecylsulfonamido; sulfamoyl, such as N-methyl- sulfamoyl, N-ethylsulfamoyl, N,N-dipropylsulfamoyl, N-hexadecylsulfamoyl, N,N-dimethylsulfamoyl; N- [3 -(dodecyloxy)propyl] sulfamoyl, N-[4-(2,4-di- t-pentylphenoxy)butyl] sulfamoyl, N-methyl-N-tetradecylsulfamoyl and N-dodecylsulfamoyl; carbamoyl, such as N-methylcarbamoyl, N,N-dibutyl- carbamoyl, N-octadecylcarbamoyl, N-[4-(2,4-di-t-pentylphenoxy)butyl]- carbamoyl, N-methyl-N-tetradecylcarbamoyl and N,N-di-octylcarbamoyl; acyl, such as acetyl, (2,4-di-t-amylphenoxy)acetyl, phenoxycarbonyl, -dodecyloxy- phenoxycarbonyl, methoxycarbonyl, butoxyca bonyl, tetradecyloxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl, 3-pentadecyloxycarbonyl and dodecyl- oxycarbonyl; sulfonyl, such as methoxysulfonyl, octyloxysulfonyl, tetradecyl- oxysulfonyl, 2-ethylhexyloxysulfonyl, phenoxysulfonyl, 2,4-di-t-pentyl- phenoxysulfonyl, methylsulfonyl, octylsulfonyl, 2-ethylhexylsulfonyl, dodecylsulfonyl, hexadecylsulfonyl, phenylsulfonyl, 4-nonylphenylsulfonyl and -toluylsulfonyl; sulfonyloxy, such as dodecylsulfonyloxy and hexadecyl- sulfonyloxy; sulfinyl, such as methylsulfinyl, octylsulfinyl, 2-ethylhexylsulfinyl, dodecylsulfinyl, hexadecylsulfinyl, phenylsulfinyl, 4-nonylphenylsulfinyl and ?-toluylsulfinyl; thio, such as ethylthio, octylthio, benzylthio, tetradecylthio, 2-(2,4-di-t-pentylρhenoxy)-ethylthio, phenylthio, 2-butoxy-5-t-octylphenylthio and j-»-tolylthio; acyloxy, such as acetyloxy, benzoyloxy, octadecanoyloxy, ?-dodecylamidobenzoyloxy, N-phenylcarbamoyloxy, N-ethylcarbamoyloxy and cyclohexylcarbonyloxy; amino, such as phenylanilino, 2-chloroanilino, diethylamino and dodecylamino; imino, such as 1 (N-phenylimido)ethyl, N-succinimido or 3-benzyl-hydantoinyl; phosphate, such as dimethylphosphate and ethylbutylphosphate; phosphite, such as diethyl and dihexylphosphite; a heterocyclic group, a heterocyclic oxy group or a heterocyclic thio group, each of which may be substituted and which contain a 3 to 7 membered heterocyclic ring composed of carbon atoms and at least one hetero atom selected from the group consisting of oxygen, nitrogen and sulfur, such as 2-furyl, 2-thienyl,

2-benzimidazolyloxy or 2-benzothiazolyl; quaternary ammonium, such as triethylammonium; and silyloxy, such as trimethylsilyloxy. If desired, the substituents may themselves be further substituted one or more times with the described substituent groups. The particular substituents used may be selected by those skilled in the art to attain the desired photographic properties for a specific application and can include, for example, hydrophobic groups, solubilizing groups, blocking groups, releasing or releasable groups. Generally, the above groups and substituents thereof may include those having up to 48 carbon atoms, typically 1 to 36 carbon atoms and usually less than 24 carbon atoms, but greater numbers are possible depending on the particular substituents selected. Representative substituents on ballast groups include alkyl, aryl, alkoxy, aryloxy, alkylthio, hydroxy, halogen, alkoxycarbonyl, aryloxycarbonyl, carboxy, acyl, acyloxy, amino, anilino, carbonamido, carbamoyl, alkylsulfonyl, arylsulfonyl, sulfonamido and sulfamoyl groups, wherein the substituents typically contain 1 to 42 carbon atoms. Such substituents can also be further substituted. Embodiments of the invention exhibit reduction of low unwanted side-band absorption, providing a colour record having improved hue. The dispersion of the coupler(s), for use in the invention can be incorporated into the photographic element as emulsified photographic dispersions, prepared by dissolving the materials in a solvent, which may be a compound of formula (IN) or additionally one or more high-boiling permanent organic solvents, preferably a high-boiling ester such as, for example, acetyl tributyl citrate, with or without a low-boiling or partially water-soluble auxiliary organic solvent. Normally such an additional solvent will be other than a phenol substituted at the para position with a nitrogen- or sulfur-bonded group. A blend of permanent solvents may be advantageous to optimise the desired features, such as solubility, dye hue, thermal or light stability or the coupling reactivity of the dispersions. The resulting organic solution may then be mixed with an aqueous gelatin solution and the mixture passed through a mechanical mixing device suitable for high-shear or turbulent mixing generally suitable for preparing photographic emulsified dispersions, as described in EP-A-1 037 103, incorporated herein by reference. The dispersion particles preferably have an average particle size of up to 2μm, generally from about 0.02 to 2μm, more preferably from about 0.02 to 0.5μm, especially from about 0.02 to 0.3μm. These methods are described in detail in U.S. Patent Nos. 2,322,027, 2,787,544, 2,801,170, 2,801,171, 2,949,360 and 3,396,027, the disclosures of which are incorporated by reference herein. The aqueous phase of the coupler dispersion(s) for use in the invention preferably comprises gelatin as a hydrophilic colloid. This may be gelatin or a modified gelatin such as acetylated gelatin, phthalated gelatin or oxidized gelatin. Gelatin may be base-processed, such as lime-processed gelatin, or may be acid-processed, such as acid-processed ossein gelatin. Other hydrophilic colloids may also be used, such as a water-soluble polymer or copolymer including, but not limited to poly(vinyl alcohol), partially hydrolyzed poly(vinyl acetate-co-vinyl alcohol), hydroxyethyl cellulose, ρoly(acrylic acid), poly(l-vinylpyrrolidone), poly(sodium styrene sulfonate), poly(2-acrylamido- 2-methane sulfonic acid) and polyacrylamide. Copolymers of these polymers with hydrophobic monomers may also be used. A surfactant may be present in either the aqueous phase or the organic phase or the dispersions can be prepared without any surfactant present. Surfactants may be catiomc, anionic, zwitterionic or non-ionic. Ratios of surfactant to liquid organic solution typically are in the range of 0.5 to 25wt.% for forming small particle photographic dispersions. In a preferred embodiment of the invention, an anionic surfactant is contained in the aqueous gelatin solution. Particularly preferred surfactants which are employed in the present invention include an alkali metal salt of an alkarylene sulfonic acid, such as the sodium salt of dodecylbenzene sulfonic acid or sodium salts of isopropyl-naphthalene sulfonic acids, such as mixtures of di-isopropyl- and tri-isopropylnaphthalene sodium sulfonates; an alkali metal salt of an alkyl sulfuric acid, such as sodium dodecyl sulfate; or an alkali metal salt of an alkyl sulfosuccinate, such as sodium bis (2- ethylhexyl) succinic sulfonate. Aqueous dispersions of high-boiling solvents can be prepared similarly to the coupler dispersion(s), e.g. by adding the solvent(s) to an aqueous medium and subjecting such mixture to high shear or turbulent mixing as described above. The aqueous medium is preferably a gelatin solution and surfactants may also be used as described above. Additionally, a hydrophobic additive may be dissolved in the solvent to prevent particle growth as described in U.S. Patent No. 5,468,604, the disclosure of which is incorporated by reference. The mixture is then passed through a mechanical mixing device such as a colloid mill, homogenizer, microfluidizer, high-speed mixer or ultrasonic dispersing apparatus to form small particles of the organic solvent suspended in the aqueous phase. These methods are described in detail in the aforementioned references on dispersion making. An aqueous coating solution in accordance with the present invention may then be prepared by combining the coupler dispersion(s) with the separate dispersion of the high-boiling organic solvent(s). Other ingredients may also be contained in this solution such as silver halide emulsions, dispersions or solutions of other photographically useful compounds, additional gelatin, or acids and bases to adjust the pH. These ingredients may then be mixed with a mechanical device at an elevated temperature (e.g. 30 to 50C) for a short period of time (e.g. 5 min to 4 h) prior to coating. The materials for use in the invention can be used in any of the ways and in any of the combinations known in the art. Typically, the materials are incorporated in a silver halide emulsion and the emulsion coated as a layer on a support to form part of a photographic element. Alternatively, unless provided otherwise, they can be incorporated at a location adjacent to the silver halide emulsion layer where, during development, they will be in reactive association with development products such as oxidized colour developing agent. Thus, as used herein, the term "associated" signifies that the compound is in the silver halide emulsion layer or in an adjacent location where, during processing, it is capable of reacting with silver halide development products. Suitable laydowns of total coupler are from about 0.05 mmol/m to about 1.5 mmol/m², preferably from about 0.15 mmol/m² to about 1 mmol m², more preferably from about 0.15 mmol/m² to about 0.5 mmol/m². The molar ratio of de-aggregating compound of formula (I) to total coupler of formula (H) is from about 0.01:1 to about 4:1, preferably from about 0.25:1 to about 2:1, more preferably from about 0.4:1 to about 1.5:1. The ratio of total solvent (including compound of formula (IN)) to total coupler (by weight) is from about 0.2:1 to about 5:1, preferably from about 0.5:1 to about 4:1, more preferably from about 0.5:1 to about 2:1. The ratio of stabilizer to total coupler (by weight) is from about 0.1:1 to about 4:1, preferably from about 0.1:1 to about 2:1, more preferably from about 0.1:1 to about 1.5:1. The photographic elements comprising coupler dispersion(s) for use in the invention can be single colour elements or multicolour elements. Multicolour elements contain image dye-forming units sensitive to each of the three primary regions of the spectrum. Each unit can comprise a single emulsion layer or multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. hi an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer. A typical multicolour photographic element comprises a support bearing a cyan dye image-forming unit comprised of at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye- forming coupler, a magenta dye image-forming unit comprising at least one green- sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler. The element can be employed with a reflective support, as described in U.S. Patent No. 5,866,282. The element can contain additional layers, such as filter layers, interlayers, overcoat layers and subbing layers. If desired, the photographic element can be used in conjunction with an applied magnetic layer as described in Research Disclosure, November 1992, Item 34390 published by Kenneth Mason Publications, Ltd., Dudley Annex, 12a North Street, Emsworth, Hampshire P010 7DQ, ENGLAND, and as described in Hatsumi Kyoukai Koukai Gihou No. 94-6023, published March 15, 1994, available from the Japanese Patent Office, the contents of which are incorporated herein by reference. When it is desired to employ the inventive materials in a small format film, Research Disclosure, June 1994, Item 36230 provides suitable embodiments. In the following discussion of suitable materials for use in the emulsions and elements of this invention, reference will be made to Research

Disclosure, September 1994, Item 36544, available as described above, which will be identified hereafter by the term "Research Disclosure". The contents of the Research Disclosure, including the patents and publications referenced therein, are incorporated herein by reference, and the Sections hereafter referred to are Sections of the Research Disclosure. Except as provided, the silver halide emulsion containing elements employed in this invention can be either negative-working or positive- working as indicated by the type of processing instructions (i.e. colour negative, reversal or direct positive processing) provided with the element. Suitable emulsions and their preparation as well as methods of chemical and spectral sensitization are described in Sections I through N. Various additives such as UV dyes, brighteners, antifoggants, stabilizers, light absorbing and scattering materials and physical property modifying addenda such as hardeners, coating aids, plasticizers, lubricants and matting agents are described, for example, in Sections II and VI through Vπi. Colour materials are described in Sections X through XIII. Scan facilitating is described in Section XIN. Supports, exposure, development systems and processing methods and agents are described in Sections XV to XX. Certain desirable photographic elements and processing steps, particularly those useful in conjunction with colour reflective prints, are described in Research Disclosure, Item 37038, February 1995. US Patent No. 5,558,980 discloses loaded latex compositions, such as poly- and t-butyl-acrylamides which can be incorporated into any photographic coating in any layer to provide extra dye stability. Couplers that form cyan dyes upon reaction with oxidized colour developing agents are typically phenols, naphthols or pyrazoloazoles, described in such representative patents and publications as U.S. Patent Nos. 2,367,531 , 2,423,730, 2,474,293, 2,772,162, 2,895,826, 3,002,836, 3,034,892, 3,041,236, 4,333,999 and 4,883,746, EP-A-0 544322, EP-A-0 556 700, EP-A-0 556 777, EP-A-0 565 096, EP-A-0 570 006 and EP-A-0 574 948 and "Farbkuppler-eine Literaturiibersicht," published in Agfa Mitteilungen, Band HI, pp. 156-175 (1961). Typical cyan couplers are represented by the following formulae:-

wherein R_l5 R₅ and R₈ each represent a hydrogen or a substituent,

R_j represents a substituent, R₃, R₄ and R₇ each represent an electron attractive group having a Hammett's substituent constant Spara of 0.2 or more and the sum of the Sp ra values of R₃ and R₄ is 0.65 or more, R₆ represents an electron attractive group having a Hammett's substituent constant Spara of 0.35 or more, X represents a hydrogen or a coupling-off group, Z- represents nonmetallic atoms necessary for forming a nitrogen-containing, six-membered, heterocyclic ring which has at least one dissociative group, Z₂ represents — C(R7)= and — = and Z₃ and Z₄ each represent — CtR_g)^ and — N= or by the formulae : -

CYAN-5 CYAN-6 wherein R_g represents a substituent (preferably a carbamoyl, ureido, or carbonamido group), R₁₀ represents a substituent (preferably individually selected from halogen, alkyl, and carbonamido groups), R_n represents a ballast substituent; R₁₂ represents hydrogen or a substituent (preferably a carbonamido or sulfonamido group), X represents a hydrogen or a coupling-off group, and m is an integer from 1 to 3. Couplers that form magenta dyes upon reaction with oxidized colour developing agent are described in such representative patents and publications as U.S. Patent Nos. 2,311,082, 2,343,703, 2,369,489, 2,600,788, 2,908,573, 3,062,653, 3,152,896, 3,519,429, 3,758,309, 4,540,654 and "Farbkuppler-eine Literaturubersicht," published in Agfa Mitteilungen, Band HI, pp. 126-156 (1961). Preferably such couplers are pyrazolones, pyrazolotriazoles or pyrazolobenzimidazoles that form magenta dye^'s upon reaction with oxidized colour developing agents. Especially preferred couplers are lH-pyrazolo [5,l-c]-l,2,4-triazole and lH-pyrazolo [l,5-b]-l,2,4-triazole. Examples of lH-pyrazolo [5,l-c]-l,2,4- triazole couplers are described in U.K. Patent Nos. 1,247,493, 1,252,418, 1,398,979, U.S. Patent Nos. 4,443,536, 4,514,490, 4,540,654, 4,590,153, 4,665,015, 4,822,730, 4,945,034, 5,017,465 and 5,023,170. Examples of lH-pyrazolo [l,5-b]-l,2,4-triazoles can be found in EP-A-0 176 804, EP-A-0 177 765, U.S Patent Nos. 4,659,652, 5,066,575 and 5,250,400. Typical pyrazoloazole and pyrazolone couplers are represented by the following formulae:

wherein Ra and R are independently hydrogen or a substituent, Rc is a substituent (preferably an aryl group), Rd is a substituent (preferably an anilino, carbonamido, ureido, carbamoyl, alkoxy, aryloxycarbonyl, alkoxycarbonyl or N-heterocyclic group), X is hydrogen or a coupling-off group, and Z_a, b and Zc are independently a substituted methine group, =N — , =C — or — NH — , provided that one of either the Z_a — Zb bond or the Zb — Z_c bond is a double bond and the other is a single bond, and when the Zb — Z_c bond is a carbon-carbon double bond, it may form part of an aromatic ring, and at least one of Za, Zb, and Zc is a methine group connected to the group Rb- Specific examples of such couplers are:

M-l

M-2

M-3

M-4 Couplers that form yellow dyes upon reaction with oxidized colour developing agent are described in such representative patents and publications as U.S. Patent Nos. 2,298,443, 2,407,210, 2,875,057, 3,048,194, 3,265,506, 3,447,928, 3,960,570, 4,022,620, 4,443,536, 4,910,126 and 5,340,703 and "Farbkuppler-eine Literaturubersicht", published in Agfa Mitteilungen, Band IH, pp. 112-126 (1961). Such couplers are typically open chain ketomethylene compounds. Also preferred are yellow couplers such as described, for example, in EP-A-0 482 552, EP-A-0 510 535, EP-A-0 524 540, EP-A-0 543 367 and U.S. Patent No. 5,238,803. For improved colour reproduction, couplers which give yellow dyes that cut off sharply on the long wavelength side are particularly preferred (see, for example, U.S. Patent No. 5,360,713). Typical preferred yellow couplers are represented by the following formulae:

wherein R-, R_j, Q₁ and Q₂ are each a substituent, X is hydrogen or a coupling-off group, Y is an aryl group or a heterocyclic group, Q₃ is an organic residue required to form a nitrogen-containing heterocyclic group together with the >N — , and Q₄ are nonmetallic atoms necessary to form a 3- to 5-membered hydrocarbon ring or a 3- to 5-membered heterocyclic ring which contains at least one hetero atom selected from nitrogen, oxygen, sulfur and phosphorous in the ring. Particularly preferred is when Q₁ and Q₂ are each an alkyl group, an aryl group or a heterocyclic group, and R₂ is an aryl or tertiary alkyl group. Preferred yellow couplers have the following structures:

Y-l

Y-2

Y-4

Y-5

Y-6

Couplers that form colourless products upon reaction with oxidized colour developing agent are described in such representative patents as U.K. Patent No. 861, 138, U.S. Patent Nos. 3,632,345, 3,928,041, 3,958,993 and 3,961,959. Typically such couplers are cyclic carbonyl-containing compounds that form colourless products on reaction with an oxidized colour developing agent. Couplers that form black dyes upon reaction with oxidized colour developing agent are described in such representative patents as U.S. Patent Nos. 1,939,231, 2,181,944, 2,333,106 and 4,126,461, German OLS No. 2,644,194 and German OLS No. 2,650,764. Typically, such couplers are resorcinols or m-aminophenols that form black or neutral products on reaction with oxidized colour developing agent. In addition to the foregoing, so-called "universal" or "washout" couplers may be employed. These couplers do not contribute to image dye- formation. Thus, for example, a naphthol having an unsubstituted carbamoyl or one substituted with a low molecular weight substituent at the 2- or 3- position may be employed. Couplers of this type are described, for example, in U.S. Patent Nos. 5,026,628, 5,151,343 and 5,234,800. It may be useful to use additional couplers any of which may contain known ballasts or coupling-off groups such as those described in

U.S. Patent Nos. 4,301,235, 4,853,319 and 4,351,897. The coupler may contain solubilizing groups such as described in U.S. Patent No. 4,482,629. The coupler may also be used in association with "wrong" coloured couplers (e.g. to adjust levels of interlayer correction) and, in colour negative applications, with masking couplers such as those described in EP-A-0 213 490, Japanese Published

Application 58-172,647, U.S. Patent Nos. 2,983,608, 4,070,191 and 4,273,861, German Applications DE 2,706,117 and DE 2,643,965, UK Patent No. 1 ,530,272 and Japanese Application 58-113935. The masking couplers may be shifted or blocked, if desired. The materials for use in the invention may be used in association with materials that accelerate or otherwise modify the processing steps e.g. of bleaching or fixing to improve the quality of the image. Bleach accelerator releasing couplers such as those described in EP-A-0 193 389, EP-A-0 301 477 and in U.S. Patent Nos. 4,163,669, 4,865,956 and 4,923,784, maybe useful. Also contemplated is use of the compositions in association with nucleating agents, development accelerators or their precursors (UK Patent Nos. 2,097,140 and 2,131,188); electron transfer agents (U.S. Patent Nos. 4,859,578 and 4,912,025); antifogging and anti colour-mixing agents such as derivatives of hydroquinones, aminophenols, amines, gallic acid; catechol; ascorbic acid; hydrazides; sulfonamidophenols and non colour-forming couplers. The materials for use in the invention may also be used in combination with filter dye layers comprising colloidal silver sol or yellow, cyan and/or magenta filter dyes, either as oil-in-water dispersions, latex dispersions or as solid particle dispersions. Additionally, they may be used with "smearing" couplers (e.g. as described in U.S. Patent Nos. 4,366,237, 4,420,556, 4,543,323 and in EP-A-0 096 570). Also, the compositions may be blocked or coated in protected form as described, for example, in Japanese Application 61/258,249 or U.S. Patent No. 5,019,492. The materials for use in the invention may further be used in combination with image-modifying compounds such as "Developer Inhibitor- Releasing" compounds (DIRs). DIRs useful in conjunction with the compositions of the invention are known in the art and examples are described in U.S. Patent Nos. 3,137,578, 3,148,022, 3,148,062, 3,227,554, 3,384,657, 3,379,529, 3,615,506, 3,617,291, 3,620,746, 3,701,783, 3,733,201, 4,049,455, 4,095,984, 4,126,459, 4,149,886, 4,150,228, 4,211,562, 4,248,962, 4,259,437, 4,362,878, 4,409,323, 4,477,563, 4,782,012, 4,962,018, 4,500,634, 4,579,816, 4,607,004, 4,618,571, 4,678,739, 4,746,600, 4,746,601, 4,791,049, 4,857,447, 4,865,959, 4,880,342, 4,886,736, 4,937,179, 4,946,767, 4,948,716, 4,952,485, 4,956,269, 4,959,299, 4,966,835, 4,985,336 as well as in patent publications GB 1,560,240, GB 2,007,662, GB 2,032,914, GB 2,099,167, DE 2,842,063, DE 2,937,127, DE 3,636,824, DE 3,644,416 as well as the following European Patent Publications: EP-A-0 272 573, EP-A-0 335 319, EP-A-0 336 411, EP-A-0 346 899, EP-A-0 362 870, EP-A-0 365 252, EP-A-0 365 346, EP-A-0 373 382, EP-A-0 376 212, EP-A-0 377463, EP-A-0 378 236, EP-A-0 384 670, EP-A-0 396 486, EP-A-0 401 612 and EP-A-0 401 613. Such compounds are also disclosed in "Developer-Inhibitor-

Releasing (DIR) Couplers for Color Photography," CR. Barr, J.R. Thirtle and P.W. Vittum in Photographic Science and Engineering, Vol.13, p.174 (1969), incorporated herein by reference. Generally, the developer inhibitor-releasing (DIR) couplers include a coupler moiety and an inhibitor coupling-off moiety (IN). The inhibitor-releasing couplers may be of the time-delayed type (DIAR couplers) which also include a timing moiety or chemical switch which produces a delayed release of inhibitor. Examples of typical inhibitor moieties are: oxazoles, thiazoles, diazoles, triazoles, oxadiazoles, thiadiazoles, oxathiazoles, thiatriazoles, benzotriazoles, tetrazoles, benzimidazoles, indazoles, isoindazoles, mercapto- tetrazoles, selenotetrazoles, mercaptobenzothiazoles, selenobenzothiazoles, mercaptobenzoxazoles, selenobenzoxazoles, mercaptobenzimidazoles, selenobenzimidazoles, benzodiazoles, mercaptooxazoles, mercaptothiadiazoles, mercaptothiazoles, mercaptotriazoles, mercaptooxadiazoles, mercaptodiazoles, mercaptooxathiazoles, tellurotetrazoles or benzisodiazoles. In a preferred embodiment, the inhibitor moiety or group is selected from the following formulae:

—(c ₂)_m-co₂R_τττ

wherein R, is selected from the group consisting of straight and branched alkyl groups of from 1 to about 8 carbon atoms, benzyl, phenyl and alkoxy groups and such groups containing none, one or more than one such substituent, R.- is selected from R- and -SR-, R_m is a straight or branched alkyl group of from 1 to about 5 carbon atoms and m is from 1 to 3, and R^ is selected from the group consisting of hydrogen, halogen and alkoxy, phenyl and carbonamido groups, -COOR_y and -NHCOOR^., wherein R-_y is selected from substituted and unsubstituted alkyl and aryl groups. Although it is typical that the coupler moiety included in the developer inhibitor-releasing coupler forms an image dye corresponding to the layer in which it is located, it may also form a different colour as one associated with a different film layer. It may also be useful that the coupler moiety included in the developer inhibitor-releasing coupler forms colourless products and/or products that wash out of the photographic material during processing (so-called "universal" couplers). As mentioned, the developer inhibitor-releasing coupler may include a timing group, which produces the time-delayed release of the inhibitor group, such as groups using an intramolecular nucleophilic substitution reaction (U.S. Patent No. 4,248,962); groups utilizing an electron transfer reaction along a conjugated system (U.S. Patent Nos. 4,409,323, 4,421,845 and 4,861,701 and Japanese Applications 57-188035; 58-98728; 58-209736; 58-209738); groups utilizing ester hydrolysis (German Patent Application (OLS) No. 2,626,315); groups that function as a coupler or reducing agent after the coupler reaction (U.S. Patent Nos. 4,438,193 and 4,618,571) and groups that combine the features described above. It is typical that the timing group is of one of the formulae:

wherein IN is the inhibitor moiety, Z is selected from the group consisting of nitro, cyano, alkylsulfonyl, sulfamoyl (-SO₂NR₂) and sulfonamido (-NRSO₂R) groups, n is 0 or 1, and R_yι is selected from the group consisting of substituted and unsubstituted alkyl and phenyl groups. The oxygen atom of each timing group is bonded to the coupling-off position of the respective coupler moiety of the DIAR. The timing or linking groups may also function by electron transfer down an unconjugated chain. Linking groups are known in the art under various names. Often they have been referred to as groups capable of utilizing a hemiacetal or iminoketal cleavage reaction or as groups capable of utilizing a cleavage reaction due to ester hydrolysis such as U.S. Patent No. 4,546,073. This electron transfer down an unconjugated chain typically results in a relatively fast decomposition and the production of carbon dioxide, formaldehyde or other low molecular weight by-products. The groups are exemplified in EP-A-0464 612, EP-A-0 523 451, U.S. Patent No. 4,146,396 and Japanese Kokais 60-249148 and 60-249149. Suitable developer inhibitor-releasing couplers that may be included in photographic light sensitive emulsion layer include, but are not limited to, the following:

It is also contemplated that the concepts of the present invention may be employed to obtain reflection colour prints as described in Research Disclosure, November 1979, Item 18716, available from Kenneth Mason Publications, Ltd, Dudley -Annex, 12a North Street, Emsworth, Hampshire P0101 7DQ, England, incorporated herein by reference. Materials for use in the invention may be coated on pH adjusted support as described in U.S. Patent No. 4,917,994, on a support with reduced oxygen permeability (EP-A-0 553 339), with epoxy solvents (EP-A-0 164 961), with nickel complex stabilizers (for example U.S. Patent Nos. 4,346,165, 4,540,653 and 4,906,559), with ballasted chelating agents such as those in U.S. Patent No. 4,994,359 to reduce sensitivity to polyvalent cations such as calcium and with stain reducing compounds such as described in U.S. Patent No. 5,068,171. Other compounds useful in combination with those for use in the invention are disclosed in Japanese Published Applications described in Derwent Abstracts having accession numbers as follows: 90-072,629, 90-072,630, 90-072,631, 90-072,632, 90-072,633, 90-072,634, 90-077,822, 90-078,229, 90-078,230, 90-079,336, 90-079,337, 90-079,338, 90-079,690, 90-079,691, 90-080,487, 90-080,488, 90-080,489, 90-080,490, 90-080,491, 90-080,492, 90-080,494, 90-085,928, 90-086,669, 90-086,670, 90-087,360, 90-087,361, 90-087,362, 90-087,363, 90-087,364, 90-088,097, 90-093,662, 90-093,663, 90-093,664, 90-093,665, 90-093,666, 90-093,668, 90-094,055, 90-094,056, 90-103,409, 83-62,586 and 83-09,959. Any silver halide combination can be used for the photographic element, such as silver chloride, silver chlorobromide, silver chlorobromoiodide, silver bromide, silver bromoiodide or silver chloroiodide. In cases where the emulsion composition is a mixed halide, the minor component may be added in the crystal formation or after formation as part of the sensitization or melting. The shape of the silver halide emulsion grain can be cubic, pseudo-cubic, octahedral, tetradecahedral or tabular. The emulsions may be precipitated in any suitable environment such as a ripening environment, a reducing environment or an oxidizing environment. Specific references relating to the preparation of emulsions of differing halide ratios and morphologies are described in EP-A-1 321 812 and the documents referenced therein, each of these being incorporated herein by reference. Reducing agents present in the dispersing medium during precipitation can be employed to increase the sensitivity of the grains. Conversely, oxidizing agents may be present during precipitation, used as a pre-treatment of the dispersing medium (gelatin) or added to the emulsion after grain formation before or during sensitization, in order to improve the sensitivity/fog position of the silver halide emulsion or minimize residual ripening agent. Chemically sensitized core grains can serve as hosts for the precipitation of shells. Dopants (any grain occlusions other than silver and halide ions) can be employed to modify grain structure and properties as described in EP-A-1 321 812, incorporated herein by reference. Periods 3-7 ions, including Group VITI metal ions (Fe, Co, Ni and platinum metals (pm) Ru, Rh, Pd, Re, Os, Ir and Pt), Mg, Al, Ca, Sc, Ti, V, Cr, Mn, Cu Zn, Ga, As, Se, Sr, Y, Mo, Zr, Nb, Cd, In, Sn, Sb, Ba, La, W, Au, Hg, Tl, Pb, Bi, Ce and U can be introduced during precipitation. For some uses any polyvalent metal ion (pvmi) is effective. The selection of the host grain and the dopant, including its concentration and, for some uses, its location within the host grain and/or its valence can be varied to achieve aim photographic properties, as illustrated by B. H. Carroll, "Indium Sensitization: A Literature Review", Photographic Science and Engineering, Vol. 24, No. 6 Nov./Dec. 1980, (265-267). Dopants can be added in conjunction with addenda, antifoggants, dye and stabilizers either during precipitation of the grains or post precipitation, possibly with halide ion addition. These methods may result in dopant deposits near or in a slightly subsurface fashion, possibly with modified emulsion effects Desensitizing, contrast increasing or reciprocity failure reducing ions or complexes are typically dopants which function to trap photogenerated holes or electrons by introducing additional energy levels deep within the bandgap of the host material. Examples include, but are not limited to, simple salts and complexes of Groups 8-10 transition metals (e.g. rhodium, iridium, cobalt, ruthenium, and osmium) and transition metal complexes containing nitrosyl or thionitrosyl ligands as described by McDugle et al U.S. Patent No. 4,933,272. Specific examples are disclosed in EP-A-1 321 812, incorporated herein by reference. Emulsion addenda that adsorb to grain surfaces, such as antifoggants, stabilizers and dyes can also be added to the emulsions during precipitation. Chemical sensitization of the materials in this photographic element is accomplished by any of a variety of known chemical sensitizers. The emulsions described herein may or may not have other addenda such as sensitizing dyes, supersensitizers, emulsion ripeners, gelatin or halide conversion restrainers present before, during or after the addition of chemical sensitization. The use of sulfur, sulfur plus gold, or gold only sensitizations are very effective sensitizers. Typical gold sensitizers are chloroaurates, aurous dithiosulfate, aqueous colloidal gold sulfide or aurous bis(l ,4,5-trimethyl- l,2,4-triazolium-3-thiolate) tetrafluoroborate (e.g. U.S Patent No. 5,049,485).

Sulfur sensitizers may include thiosulfate, thiocyanate, NN-carbothioyl-bis

(N-methylglycine) or l,3-dicarboxymethyl-l,3-dimethyl-2-thiourea sodium salt. The addition of one or more antifoggants as stain reducing agents is also common in silver halide systems. Tetrazaindenes, such as 4-hydroxy-

6-methyl-(l,3,3a,7)-tetrazaindene, are commonly used as stabilizers. Also useful are mercaptotetrazoles such as l-phenyl-5-mercaptotetrazole or acetamido- l-phenyl-5-mercaptotetrazole. Arylthiosulfonates, such as tolylthiosulfonate

(optionally used with arylsulfinates such as tolylsulfinate) or esters thereof are especially useful (e.g. U.S. Patent No. 4,960,689). The use of water-soluble disulfides is illustrated in U.S. Patent No. 5,830,631. Tabular grain silver halide emulsions may be used in the present invention. Specifically contemplated tabular grain emulsions are those in which greater than 50 percent of the total projected area of the emulsion grains are accounted for by tabular grains having a thickness of less than 0.3 micrometers (0.5 micrometers for blue sensitive emulsion) and an average tabularity (T) of greater than 25 (preferably greater than 100), where the term "tabularity" is employed in its art recognized usage as T = ECD/t² wherein ECD is the average equivalent circular diameter of the tabular grains in micrometers and t is the average thickness in micrometers of the tabular grains. The average useful ECD of photographic emulsions can range up to about 10 micrometers, although in practice emulsion ECDs seldom exceed about 4 micrometers. Since both photographic speed and granularity increase with increasing ECDs, it is generally prefened to employ the smallest tabular grain ECDs compatible with achieving aim speed requirements. Emulsion tabularity increases markedly with reductions in tabular grain thickness. It is generally prefened that aim tabular grain projected areas be satisfied by thin (t < 0.2 micrometer) tabular grains. To achieve the lowest levels of granularity it is prefened that aim tabular grain projected areas be satisfied with ultrathin (t < 0.06 micrometer) tabular grains. Tabular grain thicknesses typically range down to about 0.02 micrometer. However, still lower tabular grain thicknesses are contemplated. For example, Daubendiek et al U.S. Patent No.

4,672,027 reports a 3 mol percent iodide tabular grain silver bromoiodide emulsion having a grain thickness of 0.017 micrometer. Ultrathin tabular grain high chloride emulsions are disclosed by Maskasky in U.S. Patent No. 5,217,858. As noted above tabular grains of less than the specified thickness account for at least 50 percent of the total grain projected area of the emulsion. To maximize the advantages of high tabularity it is generally prefened that tabular grains satisfying the stated thickness criterion account for the highest conveniently attainable percentage of the total grain projected area of the emulsion. For example, in prefened emulsions, tabular grains satisfying the stated thickness criteria above account for at least 70 percent of the total grain projected area. In the highest performance tabular grain emulsions, tabular grains satisfying the thickness criteria above account for at least 90 percent of total grain projected area. Suitable tabular grain emulsions can be selected from among a variety of conventional teachings, such as those of the following: Research Disclosure, Item 22534, January 1983, published by Kenneth Mason Publications, Ltd., Emsworth, Hampshire P010 7DD, England; U.S. Patent Nos. 4,439,520, 4,414,310, 4,433,048, 4,643,966, 4,647,528, 4,665,012, 4,672,027, 4,678,745, 4,693,964, 4,713,320, 4,722,886, 4,755,456, 4,775,617, 4,797,354, 4,801,522, 4,806,461, 4,835,095, 4,853,322, 4,914,014, 4,962,015, 4,985,350, 5,061,069 and 5,061,616. The emulsions can be surface-sensitive emulsions, i.e. emulsions that form latent images primarily on the surfaces of the silver halide grains, or the emulsions can form internal latent images predominantly in the interior of the silver halide grains. The emulsions can be negative-working emulsions, such as surface-sensitive emulsions or unfogged internal latent image-forming emulsions, or direct-positive emulsions of the unfogged, internal latent image-forming type, which are positive-working when development is conducted with uniform light exposure or in the presence of a nucleating agent. Photographic elements can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image and can then be processed to form a visible dye image. Processing to form a visible dye image includes the step of contacting the element with a colour developing agent to reduce developable silver halide and oxidize the colour developing agent. Oxidized colour developing agent in turn reacts with the coupler to yield a dye. With negative-working silver halide, the processing step described above provides a negative image. The described elements can be processed in the known Kodak C-41™ colour process as described in The British Journal of Photography Annual of 1988, pp 191-198. Where applicable, the element may be processed in accordance with colour print processes such as the RA-4™ process of Eastman Kodak Company as described in the British Journal of Photography Annual of 1988, pp 198-199. Such negative working emulsions are typically sold with instructions to process using a colour negative method such as the C-41™ or RA-4™ process. To provide a positive (or reversal) image, the colour development step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, and followed by uniformly fogging the element to render unexposed silver halide developable. Such reversal emulsions are typically sold with instructions to process using a colour reversal process such as E-6™. Alternatively, a direct positive emulsion can be employed to obtain a positive image. The multicolour photographic elements of the invention may be processed alternatively in a developer solution that will provide reduced processing times of one minute or less (dry to dry), and particularly reduced colour development times of less than about 25 seconds, such that all colour records are fully developed with aim sensitometry. Prefened colour developing agents are p-phenylenediamines such as: 4-amino-N,N-diethylaniline hydrochloride, 4-amino-3 -methyl-N,N-diethylaniline hydrochloride, 4-amino-3-methyl-N-ethyl-N-(2-methanesulfonamidoethyl)aniline sesquisulfate hydrate, 4-amino-3-methyl-N-ethyl-N-(2-hydroxyethyl)aniline sulfate, 4-amino-3-(2-methanesulfonamidoethyl)-N,N-diethylaniline hydrochloride and 4-amJno-N-ethyl-N-(2-methoxyethyl)-m-toluidine di-p-toluene sulfonic acid. Development is usually followed by the conventional steps of bleaching, fixing or bleach-fixing, to remove silver or silver halide, washing and drying. The coupler dispersions may be coated with emulsions to form photographic elements at very low levels of silver (less than 100 mg/m ). Reasons for doing this include reducing cost, reducing the thickness of silver halide emulsion layers to gain sharpness advantages and reducing the environmental impact during and after processing. One class of low silver photographic material is colour material intended for redox amphfication processes wherein the developed silver acts as a catalyst to the formation of the dye image. This process can take place in a low volume thin processor, such as a low volume thin tank (LVTT), for example, as disclosed in U.S. Patent No. 5,436,118. Redox amplification processes have been described for example in GB Patent Nos. 1,268,126, 1,399,481, 1,403,418, 1,560,572 and U.S. Patent Nos. 3,748,138, 3,822,129 and 4,097,278. In such processes, colour materials are developed to produce a silver image (which may contain only small amounts of silver) and are then treated with a redox-amplifying solution (or a combined developer-amplifier) to form a dye image. The invention will now be described with reference to the following examples, which should not, however, be construed as limiting the scope thereof.

EXAMPLES Preparative examples The triazine compounds of formula (I) may be prepared by methods well documented in the chemical and patent literature. Particularly useful are the methods disclosed in Swiss Patent No. 484, 695, EP-A-0 165 608, EP-A-0 779 280, EP-A-0 941 989 and US Patent Nos. 6, 284,821 and 6, 297,378. The schemes in Examples 1 and 2 taken from these references outline general synthetic methods for the preparation of triazine compounds from readily available starting materials, such as cyanuric chloride, resorcinol and m-xylene. Example 3 describes the synthesis of a triazine in which there is no free hydroxy group on a Ri, R₂ orR₃ substituent. The couplers of formula (IIA) (a), (b) (c) and (d) may be prepared according to the methods described in EP-A-0 744 655, EP-A-0 802 454, EP-A-0 269 436 and US Patent Nos. 4,916,051 respectively. The stabilizers of formula (IH) may be prepared according to the method described hereunder for stabilizer ST-1. The compounds of formula (IN) may be obtained commercially or prepared according to the methods described in Japanese Patent O.P.I. Publication Νo.19409/1981, British Patent No. 694,772, Journal of the American Chemical Society, 79, page 6524 (1957), Journal of Organic Chemistry 25, page 1000 (1960) and Organic Synthesis 31, page 33 (1951).

Example 1 Synthesis of de-aggregating compounds of formula ( Scheme A

The key intermediate 2,4,6-tris(2,4-dihydroxyphenyl)-l,3,5-triazine is prepared by the method given in H. Brunetti and CE. Luthi, Helv.Chim. Acta, 1972, 55, 1566. Resorcinol is reacted with cyanuric chloride in the presence of a Friedel-Crafts catalyst such as aluminium (TH) chloride in an aprotic solvent such as sulfolane or nitrobenzene. The tris-hydroxyphenyl triazine intermediate is then alkylated to give a product with the desired number of free 2-hydroxyphenyl substituents on the triazine ring (i.e. in the above example, four of the six available OH groups are alkylated). Suitable alkylating agents are alkyl halides, dialkyl sulfates, alkyl toluenesulfonates or dialkylalkane phosphonates. The reaction is usually carried out in an organic solvent such as 2-methoxyethanol, diglyme or dimethylformamide in the presence of an inorganic base, such as an alkali metal carbonate or hydroxide. Example 2 Synthesis of de-aggregating compounds of formula (T) Scheme B

Cyanuric chloride undergoes a Friedel-Crafts reaction with two equivalents of m-xylene in the presence of alumimum(IH) chloride in a suitable inert solvent such as dichlorobenzene. The remaining active chlorine atom of the triazine intermediate so obtained is then replaced by resorcinol and the resulting product alkylated in an analogous manner to the compounds described in Scheme A.

Example 3

Synthesis of de-aggregating compounds of formula (I) (1-33) Triazine 1-1 (7.5g, 12mmol) was heated on a steam bath in acetic anhydride (40ml) in the presence of a catalytic amount of 4-dimethylamino- pyridine (200mg). After 5h, thin layer chromataography showed two new products, the one of lower Rf being dominant (LCMS showed the lower Rf product to be desired product). Further heating did not alter the product ratio so heating was stopped and solvent removed in vacuo to give a brownish-orange oil. This was partitioned between ethyl acetate and water (250ml each) and the organic layer separated, dried (MgSO4) and solvent removed again to give the crude product as a viscous brown oil. The crude material was purified by column chromatography in 10: 1 60/80petrol-ethyl acetate, which eluted the higher Rf impurity then gave the desired compound with good separation. The appropriate fractions were combined and solvent removed to give a colourless viscous oil, 6.8g (82%). The conect structure was confirmed by ir, nmr and mass spectra. HPLC gave 98% purity.

Example 4 Synthesis of ST-1

CH₃(CH₂)₃CHCH₂OH CH₃SO₂ ^Q ^ CH₃(CH₂)₃CHCH₂O₃SCH₃ CH₂CH₃ Et₃N, THF CH₂CH₃ (1) <3

(3)

H₂, Pd/C CH₃(CH₂)₃CHCH₂O- /-NH₂

(3) E OH CH₂CH₃ (4)

(5) ST-1

2-ethylhexanol ((1) 236.6g, 1.82 mol) in 800ml tetrahydrofuran (THF) was mixed with methanesulfonylchloride (250g, 2.18 mol). The solution was cooled to 20C in an ice/acetone bath. Triethylamine (220.6g, 2.18 mol) was then added dropwise maintaining the temperature between 25 and 29C The reaction mixture was then stirred at room temperature overnight. The triethylamine hydrochloride was removed by filtration and the resulting THF solution of the mesylate (2) was concentrated to a pale yellow oil which was used as such for the next step. A mixture of the sodium salt of p-nitrophenol (39.5g, 0.2 mol), the mesylate ((2), 54.0g, 0.2 mol) and dimethylformamide (DMF) (160ml) was heated for 2 days at 94C The mixture was then poured into a beaker containing ice and water. The resulting oil was taken up in ether, washed with water and saturated sodium chloride solution, dried over sodium sulfate and concentrated to yield a red/orange oil. The crude product was passed through a plug of silica gel, eluting with dichloromethane. Upon concentration the product was obtained as a pale yellow oil (3). This material (15.0g, O.Oδmol) was subjected to hydrogenation in a Pan apparatus (ethanol, 200ml, palladium on charcoal, lg). After hydrogen uptake ceased, the solution was filtered and to the filtrate was added divinyl sulfone ((5), 7.7g, 0.065mol). The reaction mixture was heated at reflux overnight and concentrated to get a viscous oil. Upon trituration with hexane, a crystalline solid (ST-1) was obtained which was further purified by recrystallisation from ethanol.

PHOTOGRAPHIC EXAMPLES Example 5 A typical coupler solution was prepared by heating to 75C mixtures of a coupler of formula (II) and a phosphoms-containing solvent of formula (IN), added at a 1 : 1.5 ratio by weight to which could be added ethyl acetate (at a 2: 1 ratio to coupler). A stabilizer of formula (III) was incorporated at a 1 :0.32 ratio of coupler to stabilizer. The compound of formula (I) was added at a 1:1 ratio by weight. Gelatin solutions made from decalcified gelatin in demineralised water and a 10% solution of surfactant Alkanol XC™ were heated at 60C In each case the coupler and gelatin solutions were combined and mixed for 3 min. using a Soniprobe (a sonification device manufactured by Lucas Dawe instruments, Great

Britain) forming a dispersion consisting of 5% coupler, 7% gelatin and 0.75% surfactant. Each dispersion was diluted to a level appropriate for coating at a coupler laydown of 0.43 mmol/m . A light-sensitive photographic multilayer coating was made to the following format shown in TABLE 1 below. The magenta dye-forming dispersions were incorporated in layer 1.

TABLE 1 STRUCTURE OF PHOTOGRAPHIC ELEMENT

Layer Component Coverage

Layer 3 Gelatin 1.00 g/m²

Layer 2 Gelatin 0.53 g/m² Hardener, H 0.11 g/m²

Layer 1 Gelatin 1.21 g/m²

(Green- Silver chloride emulsion O.lO g Ag/m² sensitive layer) Coupler(s) 0.43 mmol/m²

Support Gelatin 3.00 g/m² over polyethylene laminated paper base

Other materials which were used in the comparative dispersions in the preparation of the photographic element are shown below.

UN absorber A

UN absorber B

Compound C

O-C.H,,

(CH-^ Solvent D

O-C₄H,

CH CH₃ Solvent E O=P-(θCH₂CH(CH₂)₃CH₃)₃

Compound F

Antioxidant G

Hardener H

Processed samples were prepared by exposing the coatings through a step tablet (density range 0-3, 0.15inc.) and developed for 0.1s and processed through a Kodak Process RA-4™ as follows:- Process Step Time (min.) Temp. CO Developer 0.75 35.0 Bleach-Fix 0.75 35.0 Water wash 1.50 35.0

The processing solutions used in the above process had the following compositions (amounts/litre solution):

Developer solution

Triethanolamine 12.41g

Blankophor REU™ 2.30g

Lithium polystyrene sulfonate 0.09g N,N-Diethylhydroxylamine 4.59g

Lithium sulfate 2.70g

Developing agent, Dev-1 5.00g

1-Hydroxyethyl- 1,1 -diphosphonic acid 0.49g

Potassium carbonate, anhydrous 21.16g Potassium chloride 1.60g

Potassium bromide 7.00mg pH adjusted to 10.4 at 26.7°C

Bleach-Fix Solution of ammonium thiosulfate 71.85g

Ammonium sulfite 5.1 Og

Sodium metabisulfite lO.OOg

Acetic acid 10.20g

Ammonium ferric ethylenedi--minetetraacetate 48.58g Ethylenediaminetetraacetic acid 3.86g pH adjusted to 6.7 at 26.7C

The reflectance spectra of the image dyes of the exposed and processed samples were measured and normalised to a maximum absorption of 1.00. From these spectra the following parameters were recorded: the wavelength at maximum absorption, λ_ma_x; the half-bandwidth of each spectrum, HBW; and unwanted blue absorption in the normalised spectrum of each magenta dye, i.e. the density at 448nm (D₄₄₈). The wavelength at an absorption of 0.5 on the hypsochromic side of the spectrum ( H_H) was also measured - a higher value indicated less unwanted blue absorption, which was preferable. A nanower half- bandwidth combined with a lower D₄₄₈ value and a higher value for λπ_H indicated a less aggregated dye. The spectral values for each coupler are shown in TABLE 2 below. Maximum Status A green density was also measured and recorded as D_max in TABLE 2 below. The light stability of the image dyes was tested by exposing the processed strips to the light from a Xenon arc lamp at an intensity of 50klux for three weeks. The amount of fade from the initial density of 1.7 is reported as a percentage under the column heading "Light fade" in TABLE 2 - a lower number being better. The data in TABLE 2 show that the combination of stabilizer, de- aggregating compound and solvent represented by Element 104 provides the best coupler activity (as represented by green D_ma ), good dye hue and the best colour- fastness. When compared with elements 101 and 102, Element 103 shows the good de-aggregation properties of the triazine material 1-2, but in the absence of a stabilizer, light stability was worse than in Element 102 which had a more highly aggregated dye. This contradicts the findings in US Patent No. 5,294,528 where good light stability was reported to be the expected result of de-aggregation of the pyrazolotriazole dye. The data also show that, when combined with the de-aggregating compound and phosphorus solvent of the invention, the stabilizer ST-1 also provides better colourfastness and activity than the comparative stabilizer C (in Element 106) which is used in the examples of US Patent No. 5,541,045. Comparative Element 106 shows a narrower spectral bandwidth value than the Element 104 of the invention. However, the _HH an D₄₄₈ values show that more of the bandwidth naπowing of element 106 must be happening at the bathochromic side of the spectrum, because this element shows a little more unwanted blue absoφtion than Element 104. Element 107 has the same dispersion as Element 102 in the green- sensitive layer and Element 107 also has the same triazine laydown as Element 104 except that in Element 107 the triazine is not in the dispersion but in the UN filtration layer 2. 2-hydroxypheny triazines such as 1-2 are UN absorbers and are usually incorporated in the interlayer of photographic materials instead of being co-dispersed in the imaging layer as in Element 104. The light stability in Element 107 is better than that in Element 102, showing that extra UN absorption is better for light stability but the dye hue is much the same. Element 107 does not show the full de-aggregating effect attributable to the triazine compound, neither does it show the same level of D_max, nor light stability as Element 104. i Element 104, since the triazine is in the coupler dispersion, it not only de-aggregates the dye but also helps dye stability beyond what would have been expected from simple UN filtration.

86640/13198/04

TABLE 2

1-2 is added to layer 2 instead of the green-sensitive layer at same laydown as in Element 104

Example 6 Further examples of the invention using a slightly modified coating structure are shown below. A lower coupler laydown was used in Example 6 relative to the one used in Example 5, but the dispersions were made in the same way. In this example extra UV filtration was also provided for the light fade testing.

TABLE 3 STRUCTURE OF PHOTOGRAPHIC ELEMENT

Layer Component Coverage

Layer 2 Gelatin 1.53 g/m Hardener, H 0.11 g/m²

Layer 1 Gelatin 1.21 g/m

(Green- Silver chloride emulsion . O.lO g Ag/m sensitive layer) Coupler(s) 0.25 mmol/m²

Support Gelatin 3.00 g/m over polyethylene laminated paper base

The reflectance spectra of the image dyes of the exposed and processed samples were measured and normalised to a maximum absorption of 1.00. From these spectra the same parameters were recorded as described in Example 5. The spectral values for each coupler are shown in TABLE 5 below. For the colourfastness experiments a UV filter was placed over the top of the coating. The filter was made up of a coating of UV absorber on polyester base as shown in TABLE 4 below.

TABLE 4 Structure of UN filter Layer Component Coverage

Layer 2 Gelatin 1.00 g/m²

Layer 1 Gelatin 0.60 g/m² (UV light- UV light-absorbing agents: absorbing (UN-A:UV-B 0.85:0.15) 1.08 g/m² layer) Antioxidant, G 0.30 g/m² Solvent for UN absorbing agents, E 0.36 g/m² Hardener, H 0.08 g/m²

Support Gelatin 0.03g/m² Polyester base

The light stability of the image dyes was tested by exposing the processed strips to the light from a Xenon arc lamp at an intensity of 50klux for five weeks, while under the UN filter. The amount of fade from the initial density of 1.0 is reported as a percentage under the column heading "Light fade" in TABLE 5 - a lower number being better. The data in TABLE 5 show that the combination of the materials of the invention provide the best all-round improvements in dye hue and colourfastness. Using the comparative solvent D instead of the phosphorus solvent P-l does not have as significant an effect on colourfastness, nor on spectral properties. The data also show that when used in combination with the other materials of the invention, a phenyl triazine compound like 1-33 (which does not have a free hydroxyl group on the phenyl substituents on the triazine moiety) can also provide significant improvements in colourfastness and dye hue. Moreover, referring to Fig 1, and with reference to Elements 112-115 in TABLE 5 below identified therein, the spectra show that as more materials of the invention are codispersed in the imaging layer the dye spectra show less unwanted blue absorptions. The bathochromic regions of the spectra are not affected significantly. OUUHU/l-JJL-O/UI-

TABLES

Example 7 Further examples of the invention are shown below for another alkyl- ballasted pyrazolotriazole coupler and were prepared as follows. A typical coupler solution was prepared by dissolving a coupler of formula (It) in a phosphorus-containing solvent of formula (IV), added at a 1:1 ratio by weight to which could be added ethyl acetate (at a 2:1 ratio to coupler). A stabilizer of formula (TTT) was incorporated at a 1:0.367 molar ratio of coupler to stabilizer. The compound of formula (I) was dissolved in this solution at a 1:1 molar ratio. Gelatin solutions made from decalcified gelatin in demineralised water and a 10% solution of surfactant Alkanol XC™ were heated at 60C. In each case the coupler and gelatin solutions were combined and mixed using a Soniprobe (a sonification device manufactured by Lucas Dawe instruments, Great Britain) forming a dispersion with sufficiently small droplets consisting of 5% coupler, 7% gelatin and 0.75% surfactant. The dispersions were coated using the format described below in Table 6. TABLE 6 STRUCTURE OF PHOTOGRAPHIC ELEMENT

Layer Component Coverage

Layer 3 Gelatin 1.0 g/m² Hardener, H 0.11 g/m²

Layer 2 Gelatin 1.5 g/m² UN light-absorbing agents: (UN-A:UV-B 0.85:0.15) 0.483g/m² Antioxidant, G 66.1mg/m² Solvent for UN absorbing agents, E 0.161g/m²

Layer 1 Gelatin 1.21 g/m²

(Green- Silver chloride emulsion 0.10 g Ag/m² sensitive layer) Coupler(s) 0.25 mmol/m²

Support Gelatin 3.00 g/m² over polyethylene laminated paper base The reflectance spectra of the image dyes of the exposed and processed samples were measured and normalised to a maximum absorption of 1.00. From these spectra the same parameters were recorded as described in Example 5. The spectral values for each coupler are shown in TABLE 7 below. The light stability of the image dyes was tested by exposing the processed strips to the light from a Xenon arc lamp at an intensity of 50klux for two weeks. The amount of fade from the initial density of 1.0 is reported as a percentage under the column heading "Light fade" in TABLE 7 - a lower number being better. The data show that in comparative element 116, the dye hue provided by the coupler M-l is very hypsochromic in the absence of materials of formula (I), and colourfastness is poor. However, in Elements 117 & 118 the full combination of the materials of the invention provided a more acceptable dye hue and colourfastness is improved relative to that of Element 116.

TABLE 7

Example 8 For this example a typical coupler solution was prepared by dissolving a coupler of formula (II) in a phosphorus-containing solvent of formula (IN), added at a 1:1.5 ratio by weight of coupler to solvent. Ethyl acetate (at a 2:1 ratio to coupler) was also added to complete the dissolution of coupler. A stabilizer of formula (III) was incorporated in this solution at a 0.367 molar ratio to coupler and the compound of formula (I) was added at a 1:1 molar ratio. In those photographic elements where more than one compound of formula (I) were used, the compounds were added at an equimolar ratio to each other so that the total molar ratio of (I) to coupler was 1:1. The gelatin solutions and homogenisation were made as described in Example 7. Each dispersion was diluted to a level appropriate for coating at a coupler laydown of 0.247 mmol/m and coated in the format shown in TABLE 6 above. The photographic elements were exposed, processed and tested using the methods described in Example 7 above except that the photographic elements were faded for three weeks. The results are shown below in TABLE 8. In this example photographic elements made up using the full combination of materials of the invention are compared with a comparative element where one of the components (the stabilizer) is missing. The D₄₄₈ value in the comparative element is acceptable, so any value equal to or lower than this value is also acceptable. The data confirm what has already been observed in previous examples that when used together the materials of the invention provide good spectral and colourfastness properties. In this combination, even phenyl triazine compounds like 1-33 or 1-34 (which do not have a free hydroxyl group on the phenyl substituents on the triazine moiety) can also provide significant improvements in dye hue and colourfastness, especially if combined with a hydroxyphenyl triazine compound, as shown in elements 127 and 128.

The invention has been described in detail with particular reference to certain prefened embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

Claims

CLAIMS: 1. A photographic element comprising at least one light-sensitive silver halide emulsion layer having associated therewith in the same dispersion at least one de-aggregating compound of formula (I), at least one heterocyclic magenta dye-forming coupler of formula (IT), at least one stabilizer of formula (HI) and at least one compound of formula (TV), wherein the de-aggregating compound has the formula (I)

(0 wherein Z\ to Z₅ are independently selected from the class consisting of nitrogen atoms or unsubstituted or substituted carbon atoms, provided that (a) at least two of Z₁ to Z₅ are unsubstituted or substituted carbon atoms and (b) no more than two of Z_\ to Z₅ are carbon atoms substituted with a substituted alkoxy group; the heterocyclic magenta dye-forming coupler has the formula (II):-

(π) wherein R¹ is an electron-donating substituent; R^c is a substituent; and q is 0 to 4; Z^a represents the atoms necessary to complete an unsubstituted or substituted 5- to 10-membered heterocyclic ring or ring system which may contain one or more other heteroatoms selected from nitrogen, oxygen and sulfur; providing that each R^c is attached to a carbon atom of the ring; and X is selected from the class consisting of hydrogen or halogen or a group which is separable by the reaction of coupler with an oxidized colour developing agent; the stabilizer of formula (III) has the formula

(UT) wherein R₅ is selected from the class consisting of an unsubstituted or substituted alkyl, aryl, acyl, alkoxycarbonyl, aryloxycarbonyl, alkyl- or aryl-amido group; each Re is an independently selected substituent; or either R₅ and one Re substituent or two Re substituents may join to form an unsubstituted or substituted 5- to 10-membered ring or ring system which may contain one or more heteroatoms selected from nitrogen, oxygen and sulfur; and s is 0 to 4; provided that at least one of R₅ and a Re substituent contains a ballast group comprising at least 8 carbon atoms; and Z_b represents the atoms necessary to complete an unsubstituted or substituted 5- to 7-membered heterocyclic ring or ring system which may contain one or more other heteroatoms selected from nitrogen, oxygen and sulfur; the compound of formula (IN) has the structure

(TV) wherein R₈, R₉ and R₁₀ are independently selected from the class consisting of an unsubstituted or substituted alkyl, aryl, heterocyclyl, hetrocyclyloxy, alkoxy or aryloxy group or two of R₈,R and R₁₀ may join to form a 5- or 6-membered ring, which may be substituted, provided that the sum of the number of carbon atoms of R₈, R and R₁₀ is at least 12.

2. An element according to claim 1 wherein the de-aggregating compound of formula (I) is a pyridine, a pyrimidine, a 1,3,5 triazine, a 1,2,4 triazine or a tetrazine.

3. An element according to either of the preceding claims wherein the de-aggregating compound of formula (I) has the formula (IA),

wherein R_1; R₂ and R₃ are independently hydrogen or a substituent; and Z₂ and Z₄ are independently selected from the class consisng of nitrogen atoms or unsubstituted or substituted carbon atoms, provided that no ^"" more than two of R₁ to R₃ are carbon atoms substituted with a substituted alkoxy group.

4. An element according to any one of the preceding claims wherein the de-aggregating compound of formula (I) has the formula (IB) ^Raγ^Nγ^Rι

R₂ (IB) wherein R_1; R₂ and R₃ are independently hydrogen or a substituent.

5. An element according to either of claims 3 and 4 wherein R\, R₂ and R₃ are independently selected from the class consisting of an unsubstituted or substituted alkyl, aryl, alkyl- or aryl-amino, alkyl- or aryl-thio, alkoxy, aryloxy, alkyl- or aryl-carbamoyl, alkyl- or aryl-sulfamoyl, naphthyl or a heterocyclic ring or ring system.

6. An element according to any one of claims 3 to 5 wherein substituents on R_ls R₂ and R₃ are independently selected from hydroxy, cyano, fluoro, chloro, bromo, iodo; or an unsubstituted or substituted alkyl, aryl, heterocyclyl, alkoxy, aryloxy, alkyl- or aryl-carbonyl, alkyl- or aryl-oxycarbonyl, acyloxy, carbonamido, alkyl- or aryl-carbonamido, alkyl- or aryl- oxycarbonylamino, alkyl- or aryl-sulfonyl, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or aryl-sulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl- sulfamoylamino, alkyl- or aryl-sulfonamido, alkyl- or aryl-thio, alkyl- or aryl phosphonate, nitro, alkyl- or aryl-amino, alkyl- or aryl-ureido or alkyl- or aryl- carbamoyl group, any of which may be further substituted.

7. An element according to any one of claims 3 to 6 wherein R_l5 R₂ and R₃ are independently an unsubstituted alkyl group or a phenyl group, or an alkyl group or phenyl group substituted with one or more hydroxy, halogen, alkoxy, alkyl, alkylsulfonamido or alkylsulfonyl groups.

8. An element according to any one of claims 3 to 7 wherein each of R_l5 R₂ and R₃ is a phenyl group.

9. An element according to any one of the preceding claims wherein the compound of formula (II) has the formula (IIA)

(ΠA) wherein Z and Z are independently selected from the class consisting of -CH- groups, which may together form part of an unsubstituted or substituted phenyl ring, -CR- groups, wherein Ris a substituent, or nitrogen atoms; and R¹ and X are as defined in claim 1.

10. An element according to claim 9 wherein the compound of formula

(HA) has one of the structures:-

(a) ( )

(c) (d) wherein each of R² to R⁴ is hydrogen or an independently selected substituent; r is 0 to 4; and R¹ and X are as defined in claim 1.

11. An element according to any one of the preceding claims wherein R¹ is selected from the class consisting of an unsubstituted or substituted alkyl, aryl, alkoxy, aryloxy, acyloxy, alkyl- or aryl-thio, alkyl- or aryl-amino, alkyl- or aryl carbonamido or an alkyl- or aryl-ureido group

12. An element according to claim 11 wherein R¹ is a tertiary alkyl group.

13. An element according to any one of claims 10 to 12 wherein R and R are mdependently selected from the class consisting of an unsubstituted or unsubstituted alkyl, aryl, alkyl-or aryl-thio, alkyl- or aryl-amino or an alkyl- or aryl-carbonamido group.

14. An element according to any one of claims 10 to 13 wherein substituents for R² and R³ are independently selected from, fluoro, chloro, bromo, iodo, hydroxy; or an unsubstituted or substituted alkyl, aryl, heterocyclyl, alkoxy, aryloxy, alkyl- or aryl-oxycarbonyl, acyloxy, carbonamido, alkyl- or aryl- carbonamido, alkyl- or aryl- carbamate, alkyl- or aryl-oxycarbonylamino, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or aryl-sulfamoylamino, alkyl- or aryl-sulfonamido, alkyl- or aryl-thio, alkyl- or aryl-amino or an alkyl- or aryl- ureido or group, any of which may be further substituted.

15. An element according to any one of claims 10 to 14 wherein one of R² and R³ is an unsubstituted phenyl group or a phenyl group substituted with one or more halogen, alkyl, alkoxy, alkoxy-carbonyl, alkyl- or aryl- sulfonamido, alkyl- or aryl- carbonamido, alkyl- or aryl- carbamate or alkyl- or aryl- ureido groups, any of which may be fiirther substituted.

16. An element according to any one of claims 10 to 12 wherein R² and R³ may join to form an unsubstituted or substituted phenyl ring.

17. An element according to any one of claims 10 to 16 wherein R⁴ is selected from the class consisting of halogen and an unsubstituted or substituted alkyl or an alkyl- or aryl-carbonamido group.

18. An element according to claim 17 wherein substituents on R⁴ are selected from those as defined for R and R in claim 14 and also a cyano or an unsubstituted or substituted alkyl- or aryl-carbonyl, alkyl- or aryl-sulfonyl, alkyl- or aryl-sulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl- phosphonate, nitro or alkyl- or aryl-carbamoyl group, which may be further substituted.

19. An element according to any one of the preceding claims wherein in formula (III) R₅ is an unsubstituted or substituted alkyl or aryl group.

20. An element according to claim 19 wherein the alkyl or aryl group is substituted with an alkyl, hydroxy, alkoxy, aryloxy, acyl, acyloxy or alkoxycarbonyl group, which may in turn be substituted.

21. An element according to any one of the preceding claims wherein in formula (DI) each R₆, when present, is independently cyano, fluoro, chloro, bromo, iodo; or an unsubstituted or substituted alkyl, aryl, heterocyclyl, alkoxy, aryloxy, alkyl- or aryl-carbonyl, alkyl- or aryl-oxycarbonyl, acyloxy, carbonamido, alkyl- or aryl-carbonamido, alkyl- or aryl-oxycarbonylamino, alkyl- or aryl-sulfonyl, alkyl- or aryl-sulfonyloxy, alkyl- or aryl-oxysulfonyl, alkyl- or aryl-sulfoxide, alkyl- or aryl-sulfamoyl, alkyl- or aryl-sulfamoylamino, alkyl- or aryl-sulfonamido, alkyl- or aryl-thio, alkyl- or aryl-phosphonate, nitro, alkyl- or aryl-amino, alkyl- or aryl-ureido or alkyl- or aryl-carbamoyl group, any of which may be further substituted.

22. An element according to any one of the preceding claims wherein in formula (lit) s is 0, 1 or 2.

23. An element according to any one of the preceding claims wherein in formula (TTT) when s is 1 or 2, R is one or more halogen atoms or an alkyl, alkylsulfonamido or alkoxy group.

24. An element according to any one of the preceding claims wherein the compound of formula (TTT) has the structure

wherein R₅ and Re are as defined as in claim 1 and R₇ is selected from the class consisting of a methylene group, O and SO₂.

25. An element according to any one of the preceding claims wherein in the compound of formula (IN) R₈, R₉ and R₁₀ are independently an unsubstituted or substituted alkyl, alkoxy or aryloxy group.

26. An element according to any one of the preceding claims wherein in the compound of formula (IN) substituents on R₈, R and R₁₀ may be one or more halogen, alkyl, alkoxycarbonyl, acyloxy, alkylcarbamoyl, alkylsulfamoyl and acyl groups.

27. An element according to any one of the preceding claims wherein R₈, R₉ and R₁₀ are the same.

28. An element according to any one of the preceding claims wherein 0 the laydown oftotal coupler is from about 0.05 mmol/m to about 1.5 mmol m .

29. An element according to any one of the preceding claims wherein the molar ratio of de-aggregating compound of formula (I) to total coupler of formula (TT) is from about 0.01:1 to about 4:1.

30. An element according to any one of the preceding claims wherein the ratio oftotal solvent to total coupler (by weight) is from about 0.2:1 to about 5:1.

31. An element according to any one of the preceding claims wherein the ratio of stabilizer to total coupler (by weight) is from about 0.1 : 1 to about 4:1.

32. A multi-colour photographic element comprising a support bearing yellow, magenta and cyan image-dye-forming units comprising at least one blue-, green- or red-sensitive silver halide emulsion layer having associated therewith at least one yellow, magenta or cyan dye-forming coupler respectively, wherein the element is as defined in any one of the preceding claims.

33. A process of forming an image in a photographic element as hereinbefore defined after the element has been imagewise exposed to light, comprising contacting the element, as defined in any one of the preceding claims, with a colour developing agent.

NORMALIZED DENSITY

WAVELENGTH (nm)

FIG.1