DE69525787T2 - Process for reducing the variability of sensitometric results when developing a color photographic material under conditions of high or low activity - Google Patents

Description

The present invention relates to a method for reducing variability in sensitometry under high and low activity conditions. Another patent application relating to this is EP 0 679 942.

EP 0 561 860 describes a process for developing an imagewise exposed silver halide color material to achieve reduced variability in the sensitometric results, which comprises carrying out color development in the presence of one or a combination of black and white silver halide developing agents (herein referred to as electron transfer agents or "ETA") incorporated in the silver halide color material in an inactive form from which the active form emerges during processing, wherein development is accelerated under conditions of low activity while retarded under conditions of high activity, thereby reducing the variability in the curve of density versus logarithm of the amount of light applied (log E) caused by changes in process variables such as time, temperature, color developing agent concentration and bromide ion concentration. Model examples with the black-and-white silver halide developing agent present in the developer solution are described.

The application also mentions that the black and white silver halide developing agent, when incorporated into the photographic material, is preferably inactive until processing takes place. It could, for example, be rendered inactive by a blocking group which is hydrolyzed away when the material is immersed in the developing solution (which is normally alkaline).

EP 0 511 509 describes a method for processing a silver halide photographic material comprising a compound comprising a photographically useful group (PUG) and a blocking group and enabling a faster release of the PUG during processing.

The problem with known hydrolyzable blocked pyrazolidinone developing agents (BETAs) is that they will only be released at the required pH if the compound is relatively unstable. If the compound is stable enough that it will not break down in the material, the release will not occur quickly enough (or at all) to be of any use.

According to the present invention there is provided a method for reducing variability in sensitometry under high and low activity conditions, wherein under high activity conditions the development of a color photographic material is retarded and under low activity conditions the development is accelerated, wherein the color photographic material comprises at least one silver halide emulsion layer with an associated dye image forming coupler and which includes in a layer thereof one or more electron transfer agents which release compounds of the following general formula:

wherein:

T¹ and T² are each releasable timing groups;

n and m are each 0 or 1, where at least one value of n and m is 1;

ETA is a group which is releasable as an electron transfer agent and has one of the following formulas;

where in type (1):

R⁹⁰ and R¹⁰ are each hydrogen or a C₁₋₃ alkyl or an alkoxy group or a C₁₋₇ substituted alkyl or alkoxy group.

R¹¹ and R¹² are each hydrogen or a C₁₋₃ alkyl or hydroxyalkyl group, and wherein

at least one of R⁹9 and R¹⁰ is not hydrogen, except when R¹¹ is an acyloxyalkyl or aryloxyalkyl group, when each of R⁹9 and R¹⁰ may be hydrogen;

where in type (2):

R⁹ and R¹⁰ are each hydrogen or a C₁₋₃ alkyl group and R¹¹ and R¹² are each a C₁₋₃ alkyl or hydroxyalkyl group,

and in type (3)

R⁹9 to R¹² are each hydrogen or an unsubstituted or substituted C₁₋₁₂ alkyl or alkoxy group, wherein the total number of carbon atoms in R⁹9 to R¹² is at least 4;

wherein the one or more compounds of formula (I) comprise an ETA of type (1) alone or in combination with either type (1) and type (3) or type (2) and type (3);

x is 0, 1 or 2;

R is a substituted or unsubstituted alkyl or aryl or a photographic ballast group replacing a ring hydrogen;

y is 0, 1, 2 or 3;

R¹ is an unsubstituted or substituted alkyl;

Z is not adjacent to the ketocarbonyl group in the ring and is a group having one of the following formulas:

R² is each a substituted or unsubstituted alkyl, aryl or heterocyclic group or a carbamoyl, carbonamide, sulfamoyl, sulfonamide, ester or acid group;

is a substituted or unsubstituted alkyl, aryl or photographic ballast group ;

R⁴ is a substituted or unsubstituted alkyl or aryl;

R4' is a substituted or unsubstituted alkyl or aryl; or

and R⁵ and R⁶ are each hydrogen or unsubstituted or substituted alkyl or aryl; or the compound has one of the following structures:

the method comprising the step of treating the material with a photographic color developing composition containing a binucleophile.

The color photographic materials used or usable in the invention have the advantage of providing higher performance in the color developer, with variations in process conditions having less effect on the sensitometry than before, particularly in the case of multilayer color materials.

In the present invention, not only are low activity states accelerated by the ETA releasers used, but also the high activity states are delayed, resulting in less variability in the sensitometric results between high and low activity states. This means that the blackening curve is condensed as shown in Fig. 3-13 of the accompanying drawings.

The presence of the ETA releaser was found to reduce the variability caused by variations in development time and temperature, pH, bromide ion concentration and color developing agent concentration in the color developer solution.

The reduced risk of sensitometric changes also allows for lower refill rates, which generate overflow and waste water. The often necessary removal of bromide ions from the developer solution may also be avoidable.

The invention is explained in more detail below using embodiments shown in the drawing.

Show it

Fig. 1-13 of the attached drawings show the results of the working examples described below.

The alkyl groups represented by R to R⁶ may be alkyl groups having 1 to 25 carbon atoms (C₁₋₂₅), preferably having 1 to 6 carbon atoms (C₁₋₆). In the substituted groups, the substituents may be halogen, alkyl, alkoxy, acyloxy, aroyloxy, keto, ether, ester, sulfonamide, sulfamoyl, carbonamide or carbomoyl groups.

The binucleophile contained in the color developer composition may be, for example, hydroxylamine, hydrogen peroxide or hydrazine, all of which are substitutable, or a salt thereof. The color developer composition may be a water-soluble electron transfer agent such as pyrazolidinone.

The ETA groups have the following general formula:

wherein R⁹9 to R¹² are as previously defined.

As is known from EP 0 561 860, there are three types of behaviour that can be observed with different types of pyrazolidinone. The reduction in sensitivity to development time serves as an example.

Three types of behavior can be observed for different ETAs as follows:

Type (1): A reduction in the sensitometric range with a delay of overdevelopment and an acceleration of underdevelopment.

Type (2): A moderate reduction in the sensitometric range with a general acceleration of dye formation.

Type (3): A reduction in the sensitometric bandwidth with a general delay in dye formation.

The use of ETAs of type (2) or type (3) alone is not part of the present invention.

Type (1) is the preferred behavior exhibited by the preferred compounds, especially when used individually.

The present invention also encompasses the use of combined ETAs. Combinations of type (2) and (3) can, for example, give an overall performance that is similar to or better than that of type (1). Combinations of type (1) and (3) also give good results in that the bandwidth of the sensitometric curves is particularly well controlled.

It should be noted that the definitions of the above types of ETAs are not mutually exclusive because it is difficult to find an appropriate definition that is mutually exclusive. Examples of the three types are provided below. Furthermore, the relevant person skilled in the art will be able to determine which type a particular ETA belongs to by following the procedures described here.

Specific examples of the three types of ETAs are listed below: Type 1 Type 2 Type 3

The BETA compounds to be used in the present invention have the formula shown below. They belong to type (1) unless otherwise stated.

links of formula (1) can be incorporated into the photographic materials by known methods. For example, they can be dispersed in an organic solvent with a high boiling point. Examples of such solvents are triphenyl phosphate and dibutyl phthalate. Normally, the coupler is dissolved in the coupler solvent or a mixture of solvents, and this liquid is dispersed in an aqueous gelatin solution. Sometimes a solvent with a low boiling point is used in the coupler solvent mixture, but this is removed after the dispersion has been formed.

The present invention is particularly applicable to the processing of color negative film, but also to other processes, e.g. on color paper. The material to be processed comprises a support on which at least one silver halide emulsion layer is arranged, to which a color coupler is assigned. The term "associated" is to be understood in the sense commonly used in the art. The coupler may be incorporated in the emulsion layer or in a layer adjacent thereto. The preferred color materials comprise three dye image forming units, each containing one or more emulsion layers having couplers associated therewith, each sensitized to a different region of the spectrum. A typical color material would comprise such units sensitized to blue, green and red light, and capable of forming yellow, magenta and cyan image dyes, respectively.

Examples of color photographic materials and methods of processing them are described in Research Disclosure, No. 308119, December 1989, published by Kenneth Mason Publications, Emsworth, Hants, UK.

The following examples serve to better understand the invention.

example 1

Compound 1 was prepared as a dispersion in a coupler solution (1) (diethyl lauramide) and solution (2) (ethyl acetate) in the ratio (compound (1): solution (1): solution (2) of 1:2:3 by weight. The oil phase was then dispersed in gelatin to obtain 1.0% of compound 1 and 4.0% gelatin.

Coatings were then prepared with Compound 1 coated in a layer below a layer comprising silver halide and coupler. This is shown in Table 1 below.

Table 1 Coating format for applied BETA

(Gelatin (1.0 g/m²)

Coupler 1 (0.6 g/m²)

Tabular silver bromoiodide grains

mulsion (sensitivity = 400 ASA) (1.0 g/m²)

Gelatin (2.7 g/m²)

Tetraazinden (antifogging agent) 30 ml/silver mole

Compound 1 (0.0, 0.05, 0.1, 0.2, 0.4 g/m²)

Gelatin (2.7 g/m²)

Transparent carrier

The BETA compound was applied in a range of 0.0, 0.05, 0.1, 0.2 and 0.4 g/m2. The ETA released from the BETA is 4'-methoxyphenylpyrazolidinone.

Example 2

The coatings of Example 1 were processed in a standard C-41 developer containing 2 g/L hydroxylamine sulfate (HAS) for the following development times: 1, 2.5, 5, and 8 minutes. Figure 2 shows the sensitometric view of the control coating for these four development times. Figure 3 shows the effect of the strongest BETA coating for the same exposure times, with the curves from the control record superimposed. It can be seen that when BETA is present, the sensitometric bandwidth is reduced. This effect is similar to that produced by adding ETA to the developer, but to a lesser extent. Figure 4 plots the sensitometric bandwidth against the thickness of the BETA coating, showing that the sensitometric bandwidth increases with lower BETA.

Example 3

Compound 1 is designed to release the ETA 4'-methoxy-1-phenylpyrazolidinone by activity of the binucleophilic hydroxylamine sulfate (HAS) present in the C-41 developer at 2 g/L. Hydroxylamine is included in the C-41 developer as an antioxidant. To demonstrate the activity of hydroxylamine in releasing the ETA, some C-41 developers with HAS values of 0, 1, 2, 6, 24 and 60 g/L were prepared. The control coating and the one with the highest BETA value (0.4 g/m2) were processed in these developers and the comparison of the HAS values of 0, 6 and 60 g/L is shown in Fig. 5, 6 and 7, respectively. As can be seen, there is virtually no effect from the coated BETA without HAS, but there is an effect when HAS is present. In Fig. 1 the reduction in sensitometric sensitivity versus HAS value in the developer is plotted for a coating with BETA (0.4 g/m²) and for a coating without BETA. Here it can be seen that there is a small reduction in sensitometric sensitivity with increasing HAS value for coatings without BETA, but a much greater reduction in coatings with BETA.

Example 4

The following multi-layer structures were produced. The numbers in brackets indicate the application in g/m².

Gelatin overlayer (1.0)

UV protective layer

Blue-sensitive silver halide (0.6) high sensitivity + yellow coupler (0.18)

Blue-sensitive silver halide (0.55) low sensitivity + Yellow coupler (1.0)

Intermediate layer

High speed green sensitive silver halide (0.79) + Magenta coupler (0.11)

Green-sensitive silver halide (0.45) of medium sensitivity + Magenta coupler (0.2)

Green-sensitive silver halide (0.5) low sensitivity + Magenta coupler (0.39)

Intermediate layer

Red-sensitive silver halide (1.0) high sensitivity + cyan coupler (0.16)

Red-sensitive silver halide (0.5) of medium sensitivity + cyan coupler (0.31)

Red-sensitive silver halide (0.5) low sensitivity + cyan coupler (0.65)

Antihalation layer

Film carrier//////

where the silver halide is a bromoiodide emulsion with an average content of 3% iodide. The type, amount and location of the BETA compounds and their effect on the sensitometric results, as shown in the figures, are subject to the following changes:

1. Single BETA in multilayer; Fig. 8 and 9

a. Figure 8 compares a control layer with a BETA (compound 8) incorporated into a multilayer antihalation layer at 1.0 g/m2. The solid lines show the red record of the control layer, the dashed lines show the red record with BETA incorporated. The sensitometry bandwidth is subject to slight compression by inclusion of BETA.

b. Figure 9 compares a control layer with a BETA (compound 10) incorporated in the sensitive and low-sensitivity layers of the component of a multilayer. The solid lines show the red recording of the control layer, the dashed lines show the red recording with BETA incorporated. The bandwidth of the sensitometry is subject to a slight compression by inclusion of BETA.

2. Combinations of BETAs in multilayers; Fig. 10, 11, 12, 13.

a. Figure 10 compares the red trace of a control layer with a BETA (Compound 7) incorporated into a multilayer antihalation layer at 0.5 g/m2. This is an example of a BETA releasing an accelerating ETA, with the dashed lines for the BETA accelerated relative to the solid lines for the control layer.

b. Figure 11 compares the red record of a control layer with a BETA (Compound 9) incorporated into a multilayer antihalation layer at 0.5 g/m2. This is an example of a BETA releasing a retarding ETA, with the dashed lines for the BETA being retarded relative to the solid lines for the control layer.

c. Figure 12 compares the red record of a control layer with a combination of two BETAs (compounds 7 and 9), each incorporated in a multilayer antihalation layer at 0.5 g/m2. This is an example of a combination of an accelerating and a retarding BETA. The dashed lines for the BETA coating show that the longer development times are retarded and that the shorter development times are accelerated, both in relation to the solid lines of the control layer.

d. Figure 13 compares the red record of the example of Figure 12 with an additional 0.4 g/L of 4'-methoxy-1-phenyl-3-pyrazolidinone in the developer used for the BETA coating. In this case, the longer development times are retarded and the shorter development times are accelerated to a greater extent than would be the case without the ETA in the developer.

Claims (6)

1. A method for reducing variability in sensitometry under high and low activity conditions, wherein under high activity conditions the development of a color photographic material is retarded and under low activity conditions the development is accelerated, wherein the color photographic material comprises at least one silver halide emulsion layer with an associated dye image forming coupler, and which includes in a layer thereof one or more electron transfer agents which release compounds of the following general formula: wherein: T¹ and T² are each releasable timing groups; n and m are each 0 or 1, where at least one value of n and m is 1; ETA is a group which is releasable as an electron transfer agent and has one of the following formulas; where in type (1): R⁹⁰ and R¹⁰ are each hydrogen or a C₁₋₃ alkyl or an alkoxy group or a C₁₋₇ substituted alkyl or alkoxy group, R¹¹ and R¹² are each hydrogen or a C₁₋₃ alkyl or hydroxyalkyl group, and what at least one of R⁹9 and R¹⁰ is not hydrogen, except when R¹¹ is an acyloxyalkyl or aryloxyalkyl group, when each of R⁹9 and R¹⁰ may be hydrogen ; where in type (2): R⁹⁰ and R¹⁰ are each hydrogen or a C₁₋₃ alkyl group and R¹¹ and R¹² are each a C₁₋₃ alkyl or hydroxyalkyl group, and in Type (3) R⁹9 to R¹² are each hydrogen or an unsubstituted or substituted C₁₋₁₂ alkyl or alkoxy group, wherein the total number of carbon atoms in R⁹9 to R¹² is at least 4; wherein the one or more compounds of formula (I) comprise an ETA of type (1) alone or in combination with either type (1) and type (3) or type (2) and type (3); x is 0, 1 or 2; R is a substituted or unsubstituted alkyl or aryl or a photographic ballast group replacing a ring hydrogen; y is 0, 1, 2 or 3; R¹ is an unsubstituted or substituted alkyl; Z is not adjacent to the ketocarbonyl group in the ring and is a group having one of the following formulas: R² is each a substituted or unsubstituted alkyl, aryl or heterocyclic group or a carbamoyl, carbonamide, sulfamoyl, sulfonamide, ester or acid group; is a substituted or unsubstituted alkyl, aryl or photographic ballast group; R⁴ is a substituted or unsubstituted alkyl or aryl; R⁴ is a substituted or unsubstituted alkyl or aryl; or and R⁵ and R⁶ are each hydrogen or unsubstituted or substituted alkyl or aryl; or the compound has one of the following structures: the method comprising the step of treating the material with a photographic color developing composition containing a binucleophile. 2. Process according to claim 1, characterized in that the compound of formula (I) has an ETA group of the general formula (4) or (5), in which R⁹9 to R¹² are as defined for type (1). 3. Process according to one of the preceding claims, characterized in that the compound of formula (I) has an ETA group of the general formula (4) or (5) in which R⁹9; to R¹² are as defined for type (1) and in combination with a compound of formula (I) having an ETA group of the general formula (4) or (5) in which R⁹9; to R¹² are as defined for type (3). 4. Process according to claim 1, characterized in that the compound of formula (I) has an ETA group of the general formula (4) or (5), wherein R⁹ to R¹² are as defined for type (2) and in combination with a compound of formula (I) having an ETA group of general formula (4) or (5), wherein R⁹ to R¹² are as defined for type (3). 5. The method according to claim 1-4, characterized in that the color developing composition contains a water-soluble electron transfer agent. 6. Process according to one of claims 1-5, characterized in that the electron transfer agent is a pyrazolidinone.