EP0317885A2 - Gradation-variable black and white paper - Google Patents

Abstract

A variable-grade SW paper with only one light-sensitive silver halide emulsion layer, in which the sensitization is avoided, is obtained by sensitization with at least one compound of the formula <IMAGE> in which at least one of the radicals R1, R5 or R6 is halogen.

Description

The invention relates to a variable-gradation black and white paper (BW paper) which contains at least one emulsion which is sensitive in the green and blue spectral range, a larger exposure range being obtained in the green than in the blue.

Gradation-variable light-sensitive silver halide materials contain emulsions that are light-sensitive for different spectral ranges. Depending on the composition of the copying light, a harder or softer gradation is achieved. The emulsions are usually mixed before pouring so that only one layer has to be poured. There is a danger that sensitization occurs, ie that the sensitizing dye is desorbed from the silver halide grains of an emulsion and absorbed on the grains of an unsensitized, blue-sensitive emulsion. This is undesirable, since such a differentiated exposure by changing the copying light no longer leads to the desired result leads, under unfavorable conditions, the process of sensitization is not limited to the casting solution, but can also occur on the finished material, for example under the influence of moisture, heat or both.

In order to avoid sensitization, elaborate precautions have to be taken, for example when storing the finished material or by shortening the service life of the finished casting solution. Since these negative influences cannot always be eliminated by the producer, there has been no shortage of attempts to develop methods for avoiding sensitization. It has been proposed to remove excess sensitizing dye (DL-PS 7210), not to exceed certain critical temperatures when mixing and pouring the casting solution (US Pat. No. 2,367,508), to avoid longer standing times of the casting solutions (GB-PS 540 451, DE -OS 2 426 676) to add metal compounds to the casting solutions to prevent the diffusion of the sensitizing dyes (US Pat. No. 2,336,260) or not to mix the differently sensitized or unsensitized emulsions, but to pour them separately one above the other (GB-PS 541 515 and FR -PS 2 251 837).

As a further measure to avoid re-sensitization were the strong reduction of the sensitizer amount (US-PS 2 280 300) and the mixing of emulsions of different silver halide composition (DE-PS 1 597 476) proposed.

All of these measures did not lead to a satisfactory solution to the problem, since the sensitization during storage of the finished material could not be ruled out, the production of the material by multiple casting became much more complex, a limitation of the amount of dye to sensitivity differences and a different halide composition led to differences in image tone.

The object of the invention was therefore to find a method in which a spectral green sensitization which does not have the disadvantages described is used to produce a gradation-variable SW paper.

It has now been found that this object can be achieved by sensitizing an emulsion with a special green sensitizer in certain amounts.

worin
R₁ Wasserstoff, Halogen, Alkyl, Alkoxy,
R₂ Alkyl, Sulfoalkyl oder Carboxyalkyl,
R₃ Alkyl, Hydroxyalkyl, Acyloxyalkyl,
R₄ Alkyl, Sulfoalkyl oder Carboxylalkyl,
R₅ Halogen, Cyan, Aminocarbonyl, Trifluormethyl oder Alkoxycarbonyl,
R₆ Wasserstoff oder R₅,
X^⊖ ein Anion und
n 0 oder 1 bedeuten,
wobei wenigstens einer der Reste R₁, R₅ und R₆ Halogen ist,
n 0 bedeutet, wenn einer der Reste R₂ oder R₄ Sulfoalkyl oder Carboxyalkyl bedeutet, und n 1 bedeutet, wenn kei­ner der Reste R₂ und R₄ Sulfoalkyl oder Carboxyalkyl be­deutet,

in einer Menge von

bis

µMol/Mol

Silberhalogenid grün sensibilisiert wird, wobei d der mittlere Korn­durchmesser des Silberhalogenids in µm ist.The invention therefore relates to a variable-gradation SW paper with a light-sensitive silver halide emulsion layer, characterized in that the silver halide contains at least one compound of the formula I.

wherein
R₁ is hydrogen, halogen, alkyl, alkoxy,
R₂ alkyl, sulfoalkyl or carboxyalkyl,
R₃ alkyl, hydroxyalkyl, acyloxyalkyl,
R₄ alkyl, sulfoalkyl or carboxylalkyl,
R₅ halogen, cyan, aminocarbonyl, trifluoromethyl or alkoxycarbonyl,
R₆ is hydrogen or R₅,
X ^⊖ an anion and
n is 0 or 1,
where at least one of the radicals R₁, R₅ and R₆ is halogen,
n is 0 if one of the radicals R₂ or R₄ is sulfoalkyl or carboxyalkyl, and n is 1 if none of the radicals R₂ and R₄ is sulfoalkyl or carboxyalkyl,

in a lot of

to

µMol / Mol

Silver halide is sensitized green, whereby d is the mean grain diameter of the silver halide in µm.

Alkyl, sulfoalkyl, carboxyalkyl, hydroxyalkyl and acyloxyalkyl radicals have in particular 1 to 6 carbon atoms in the alkyl part. Acyl is preferably understood to mean C₁-C₄ alkylcarbonyl. Halogen is preferably chlorine. Alkoxy and alkoxycarbonyl have in particular 1 to 4 carbon atoms in the alkoxy part.

Suitable anions are halides such as chloride and bromide and sulfate and alkyl sulfates such as methosulfate and ethosulfate, as well as perchlorate and p-toluenesulfonate.

Suitable compounds of the formula I can be found in Table 1 below:

In a special embodiment of the invention, the green sensitizer is added to only part of the emulsion, in particular 20 to 80% by weight. In a further embodiment of the invention, the gradation-variable SW paper contains a mixture of at least one emulsion which contains at least one green sensitizer according to the invention and at least one spectrally blue (in the range from 420 to 480 μm) sensitized emulsion. The amount of blue-sensitized emulsion is in particular 15 to 60% by weight. A particularly good gradation differentiation is achieved through these measures.

worin
P die zur Ergänzung eines gegebenenfalls benzo­anellierten heterocyclischen Fünfrings erforder­lichen Glieder
Q die zur Ergänzung eines Rhodanin-, Thiohydantoin-, Thiooxazolidon- oder Thiobarbitursäurerings erfor­derlichen Ringglieder
W₁, W₂ gegebenenfalls durch Hydroxy, Carboxy oder Sulfo substituiertes C₁-C₄-Alkyl
l, m 0, 1 oder 2
R, T, O, S, N-R₇
R₇ gegebenenfalls durch Hydroxy, Carboxy oder Sulfo substituiertes C₁-C₄-Alkyl,
R₈, R₉ CH₃, CH₃O, Halogen oder - sofern R oder T Sauer­stoff ist - Phenyl bedeuten.Dyes of the following formulas, for example, are suitable as blue sensitizers:

wherein
P the links required to supplement a benzo-fused heterocyclic five-membered ring
Q the ring members required to supplement a rhodanine, thiohydantoin, thiooxazolidone or thiobarbituric acid ring
W₁, W₂ optionally substituted by hydroxy, carboxy or sulfo C₁-C₄ alkyl
l, m 0, 1 or 2
R, T, O, S, N-R₇
R₇ optionally substituted by hydroxy, carboxy or sulfo C₁-C₄-alkyl,
R₈, R₉ CH₃, CH₃O, halogen or - if R or T is oxygen - are phenyl.

The heterocyclic rings supplemented by P are preferably pyroline, oxazole, imidazole, thiazole, selenazole and their benzo-fused derivatives and 1,3,4-thiadiazole, which are substituted by C₁-C₄-alkyl, C₁-C₄-alkoxy, cyano, halogen, aryl, in particular phenyl, C₁-C₄-alkylthio, carb-C₁-C₄-alkoxy-C₁-C₄-alkylthio, carboxy-C₁-C₄-alkylthio, sulfo-C₁-C₄-alkyl and sulfoaryl, especially sulfophenyl may be substituted.

The heterocycles supplemented by Q can be substituted by C₁-C₅-alkyl or aryl, in particular phenyl, where aryl can in turn be substituted, preferably by carboxy or sulfo.

The amount of blue sensitizer is not critical; 10 to 300 μmol / mol Ag is preferably used, in particular 20 to 150 μmol.

The following dyes are particularly suitable, for example

The average grain size of the silver halide grains is preferably 0.2 to 0.6 μm, preferably 0.4 to 0.5 μm.

The silver halide is composed in particular of 20 to 80 mol% AgBr, 80 to 20 mol% AgCl and 0 to 5 mol% AgI.

The silver halide crystals can be doped with Rh³⁺, Ir⁴⁺, Cd²⁺, Zn²⁺, Pb²⁺.

The emulsion can be desalted in the customary manner (dialysis, flocculation and redispersion, ultrafiltration).

The binder is an essential component of the at least one light-sensitive layer in addition to the silver halide.

Gelatin is preferably used as the binder. However, this can be replaced in whole or in part by other synthetic, semi-synthetic or naturally occurring polymers. Synthetic gelatin substitutes are, for example, polyvinyl alcohol, poly-N-vinylpyrolidone, polyacrylamides, polyacrylic acid and their derivatives, in particular their copolymers. Naturally occurring gelatin substitutes are, for example, other proteins such as albumin or casein, cellulose, sugar, starch or alginates. Semi-synthetic gelatin substitutes are usually modified natural products. Cellulose derivatives such as hydroxyalkyl cellulose, carboxymethyl cellulose and phthalyl cellulose and gelatin derivatives, which have been obtained by reaction with alkylating or acylating agents or by grafting on polymerizable monomers, are examples of this.

The binders should have a sufficient amount of functional groups so that enough resistant layers can be produced by reaction with suitable hardening agents. Such functional groups are in particular amino groups, but also carboxyl groups, hydroxyl groups and active methylene groups.

The gelatin which is preferably used can be obtained by acidic or alkaline digestion. The production of such gelatins is described, for example, in The Science and Technology of Gelatine, published by A.G. Ward and A. Courts, Academic Press 1977, page 295 ff. The gelatin used in each case should contain the lowest possible level of photographically active impurities (inert gelatin). High viscosity, low swelling gelatins are particularly advantageous.

The silver halide present as a light-sensitive component in the photographic material can be predominantly compact crystals, which are e.g. are regular cubic or octahedral or can have transitional forms. However, platelet-shaped crystals may preferably also be present, the average ratio of diameter to thickness of which is preferably greater than 5: 1, the diameter of a grain being defined as the diameter of a circle with a circle content corresponding to the projected area of the grain.

The silver halide grains can also have a multi-layered grain structure, in the simplest case with an inner and an outer grain area (core / shell), the halide composition and / or other modifications, such as doping of the individual grain areas, being different. The grain size distribution can be both homodisperse and heterodisperse. Homodisperse grain size distribution means that 95% of the grains do not deviate more than ± 30% from the mean grain size. In addition to the silver halide, the emulsions can also contain organic silver salts, for example silver benzotriazolate or silver behenate.

Two or more kinds of silver halide emulsions, which are prepared separately, can be used as a mixture.

The photographic emulsions can be prepared using various methods (e.g. P. Glafkides, Chimie et Physique Photographique, Paul Montel, Paris (1967), GF Duffin, Photographic Emulsion Chemistry, The Focal Press, London (1966), VL Zelikman et al, Making and Coating Photographic Emulsion, The Focal Press, London (1966) from soluble silver salts and soluble halides.

The silver halide is preferably precipitated in the presence of the binder, for example the gelatin, and can be carried out in the acidic, neutral or alkaline pH range, silver halide complexing agents preferably being additionally used. The latter include, for example, ammonia, thioether, imidazole, ammonium thiocyanate or excess halide. The water-soluble silver salts and the halides are combined either in succession by the single-jet process or simultaneously by the double-jet process or by any combination of the two processes. Dosing with increasing inflow rates is preferred, the "critical" feed rate at which just yet no new germs arise, should not be exceeded. The pAg range can vary within wide limits during the precipitation, preferably the so-called pAg-controlled method is used, in which a certain pAg value is kept constant or a defined pAg profile is traversed during the precipitation. In addition to the preferred precipitation with an excess of halide, so-called inverse precipitation with an excess of silver ions is also possible. In addition to precipitation, the silver halide crystals can also grow through physical ripening (Ostwald ripening), in the presence of excess halide and / or silver halide complexing agent. The growth of the emulsion grains can even take place predominantly by Ostwald ripening, preferably a fine-grained, so-called Lippmann emulsion, mixed with a less soluble emulsion and redissolved on the latter.

The photographic emulsions may contain compounds to prevent fogging or to stabilize the photographic function during production, storage or photographic processing.

Azaindenes are particularly suitable, preferably tetra- and penta-azaindenes, in particular those which are substituted by hydroxyl or amino groups. Such connections are for example from Birr, Z. Wiss. Phot. 47 (1952), pp. 2-58. Salts of metals such as mercury or cadmium, aromatic sulfonic or sulfinic acids such as Benzenesulfinic acid, or nitrogen-containing heterocycles such as nitrobenzimidazole, nitroindazole, (subst.) Benzotriazoles or benzothiazolium salts are used. Heterocycles containing mercapto groups, for example mercaptobenzthiazoles, mercaptobenzimidazoles, mercaptotetrazoles, mercaptothiadiazoles, mercaptopyrimidines, are particularly suitable, these mercaptoazoles also being able to contain a water-solubilizing group, for example a carboxyl group or sulfo group. Other suitable compounds are published in Research Disclosure No. 17643 (1978), Section VI.

The stabilizers can precede the silver halide emulsions. added during or after their ripening. Of course, the compounds can also be added to other photographic layers which are assigned to a halogen silver layer.

Mixtures of two or more of the compounds mentioned can also be used.

The photographic emulsion layers or other hydrophilic colloid layers of the light-sensitive material produced according to the invention can contain surface-active agents for various purposes, such as coating aids, to prevent electrical charging, to improve the sliding properties, to emulsify the dispersion, to prevent adhesion and to improve the photographic characteristics ( eg acceleration of development, high contrast, sensitization etc.).

Chemical sensitization can take place through labile sulfur compounds (e.g. thiosulfate, diacetyl-thiourea), through gold-sulfur ripening or reduction ripening. Chemical sensitization can be carried out with the addition of Ir, Rh, Pb, Cd, Hg, Au, and addition of optical sensitizers or stabilizers is also possible.

The photographic material may further contain UV light absorbing compounds, whites, spacers, formalin scavengers and others.

Compounds that absorb UV light are intended on the one hand to protect the image dyes from fading by UV-rich daylight and, on the other hand, as filter dyes to absorb the UV light in daylight upon exposure and thus improve the color rendering of a film. Connections of different structures are usually used for the two tasks. Examples are aryl-substituted benzotriazole compounds (US Pat. No. 3,533,794), 4-thiazolidone compounds (US Pat. Nos. 3,314,794 and 3,352,681), benzopheno compounds (JP-A 2784/71), cinnamic acid ester compounds (US Pat. Nos. 3,705,805 and 3,707) 375), butadiene compounds (US-A 4 045 229) or benzoxazole compounds (US-A 3 700 455).

Ultraviolet absorbing couplers (such as α-naphthol type cyan couplers) and ultraviolet absorbing polymers can also be used. These ultraviolet absorbents can be fixed in a special layer by pickling.

Suitable white toners are e.g. in Research Disclosure December 1978, page 22 ff, Unit 17 643, Chapter V.

The average particle diameter of the spacers is in particular in the range from 0.2 to 10 μm. The spacers are water-insoluble and can be alkali-insoluble or alkali-soluble, the alkali-soluble ones generally being removed from the photographic material in the alkaline development bath. Examples of suitable polymers are polymethyl methacrylate, copolymers of acrylic acid and methyl methacrylate and hydroxypropyl methyl cellulose hexahydrophthalate.

The binders of the material according to the invention, in particular if gelatin is used as the binder, are hardened with suitable hardeners, for example with hardeners of the epoxy type, the ethyleneimine type, the acryloyl type or the vinylsulfone type. Diazine, triazine or 1,2-dihydroquinoline series hardeners are also suitable.

The binders of the material according to the invention are preferably hardened with instant hardeners.

Immediate hardeners are understood to mean compounds which crosslink suitable binders in such a way that the hardening is completed to the extent that no further change in the sensitometry and the Swelling of the layer structure occurs. Swelling is understood to mean the difference between the wet film thickness and the dry film thickness during the aqueous processing of the film (Photogr. Sci. Eng. 8 (1964), 275; Photogr. Sci. Eng. (1972), 449).

These hardening agents that react very quickly with gelatin are e.g. to carbamoylpyridinium salts, which are able to react with free carboxyl groups of the gelatin, so that the latter react with free amino groups of the gelatin to form peptide bonds and crosslink the gelatin.

• (a)
  
  worin
  R₁ Alkyl, Aryl oder Aralkyl bedeutet,
  R₂ die gleiche Bedeutung wie R₁ hat oder Alkylen, Arylen, Aralkylen oder Alkaralkylen bedeutet, wobei die zweite Bindung mit einer Gruppe der Formel
  
  verknüpft ist, oder
  R₁ und R₂ zusammen die zur Vervollständigung eines gegebenenfalls substituierten heterocyclischen Ringes, beispielsweise eines Piperidin-, Pipe­razin- oder Morpholinringes erforderlichen Atome bedeuten, wobei der Ring z.B. durch C₁-­C₃-Alkyl oder Halogen substituiert sein kann,
  R₃ für Wasserstoff, Alkyl, Aryl, Alkoxy, -NR₄-COR₅, -(CH₂)_m-NR₈R₉, -(CH₂)_n-CONR₁₃R₁₄ oder
  
  oder ein Brückenglied oder eine direkte Bindung an eine Polymerkette steht, wobei
  R₄, R₆, R₇, R₉, R₁₄, R₁₅, R₁₇, R₁₈, und R₁₉ Wasserstoff oder C₁-C₄-Alkyl,
  R₅ Wasserstoff, C₁-C₄-Alkyl oder NR₆R₇,
  R₈ -COR₁₀
  R₁₀ NR₁₁R₁₂
  R₁₁ C₁-C₄-Alkyl oder Aryl, insbesondere Phenyl,
  R₁₂ Wasserstoff, C₁-C₄-Alkyl oder Aryl, insbeson­dere Phenyl,
  R₁₃ Wasserstoff, C₁-C₄-Alkyl oder Aryl, insbeson­dere Phenyl,
  R₁₆ Wasserstoff, C₁-C₄-Alkyl, COR₁₈ oder CONHR₁₉,
  m eine Zahl 1 bis 3
  n eine Zahl 0 bis 3
  p eine Zahl 2 bis 3 und
  Y 0 oder NR₁₇ bedeuten oder
  R₁₃ und R₁₄ gemeinsam die zur Vervollständigung eines gegebenenfalls substituierten hetero­cyclischen Ringes, beispielsweise eines Piperidin-, Piperazin- oder Morpholinringes erforderlichen Atome darstellen, wobei der Ring z.B. durch C₁-C₃-Alkyl oder Halogen substituiert sein kann,
  Z die zur Vervollständigung eines 5- oder 6-­gliedrigen aromatischen heterocyclischen Ringes, gegebenenfalls mit anelliertem Ben­zolring, erforderlichen C-Atome und
  X^⊖ ein Anion bedeuten, das entfällt, wenn bereits eine anionische Gruppe mit dem übrigen Molekül verknüpft ist;
• (b)
  
  worin
  R₁, R₂, R₃ und X^⊖ die für Formel (a) angegebene Bedeutung besitzen.

Suitable examples of instant hardeners are, for example, compounds of the general formulas

• (a)
  
  wherein
  R₁ denotes alkyl, aryl or aralkyl,
  R₂ has the same meaning as R₁ or means alkylene, arylene, aralkylene or alkaralkylene, the second bond having a group of the formula
  
  is linked, or
  R₁ and R₂ together represent the atoms required to complete an optionally substituted heterocyclic ring, for example a piperidine, piperazine or morpholine ring, which ring can be substituted, for example, by C₁-C₃alkyl or halogen,
  R₃ for hydrogen, alkyl, aryl, alkoxy, -NR₄-COR₅, - (CH₂) _m -NR₈R₉, - (CH₂) _n -CONR₁₃R₁₄ or
  
  or a bridge link or a direct bond to a polymer chain, wherein
  R₄, R₆, R₇, R₉, R₁₄, R₁₅, R₁₇, R₁₈, and R₁₉ are hydrogen or C₁-C₄-alkyl,
  R₅ is hydrogen, C₁-C₄-alkyl or NR₆R₇,
  R₈ -COR₁₀
  R₁₀ NR₁₁R₁₂
  R₁₁ C₁-C₄ alkyl or aryl, especially phenyl,
  R₁₂ is hydrogen, C₁-C₄ alkyl or aryl, especially phenyl,
  R₁₃ is hydrogen, C₁-C₄ alkyl or aryl, especially phenyl,
  R₁₆ is hydrogen, C₁-C₄-alkyl, COR₁₈ or CONHR₁₉,
  m is a number 1 to 3
  n is a number 0 to 3
  p is a number 2 to 3 and
  Y is 0 or NR₁₇ or
  R₁₃ and R₁₄ together represent the atoms required to complete an optionally substituted heterocyclic ring, for example a piperidine, piperazine or morpholine ring, which ring can be substituted, for example, by C₁-C₃alkyl or halogen,
  Z the C atoms and required to complete a 5- or 6-membered aromatic heterocyclic ring, optionally with a fused benzene ring
  X ^{⊖ is} an anion which is omitted if an anionic group is already linked to the rest of the molecule;
• (b)
  
  wherein
  R₁, R₂, R₃ and X ^{⊖ have} the meaning given for formula (a).

The materials according to the invention are processed in the usual manner according to the processes recommended for this.

example 1

A silver chloride bromide emulsion prepared by double inlet and partial conversion with 15 mol% chloride and 85 mol% bromide, average grain diameter 0.34 μ, doped with 0.17 μmol RhCl₃ per mol Ag, is added after adding 20 μmol sodium thiosulfate per mol Ag matured to an optimal sensitivity-fog ratio. The emulsion contains 100 g AgNO₃ per kg.

This emulsion is sensitized with a green sensitizer in the amount stated (Table 1) and, after adding a wetting agent, is poured onto PE paper with a silver coating of 1.4 g per m².

• Spalte 1: der verwendete Grünsensibilisator
• Spalte 2: die Menge an Grünsensibilisator in µMol pro Mol Silber
• Spalte 3: logBU hinter Gelbfilter
• Spalte 4: logBU hinter Purpurfilter
• Spalte 5: das Sensibilisierungsmaximum in nm.

Tabelle 2 1 2 3 4 5 3 39 1,30 0,65 527 Erfindung 3 58 1,40 0,60 527 Erfindung 3 87 1,40 0,60 527 Erfindung 3 130 1,20 0,70 527 Erfindung 5 87 1,20 0,75 545 Erfindung 2 87 1,40 0,80 525 Erfindung 1 39 1,40 0,70 532 Erfindung 1 58 1,50 0,65 532 Erfindung 1 87 1,50 0,65 532 Erfindung 3 240 0,75 0,70 527 Vergleich 5 240 0,80 0,75 545 Vergleich 2 240 0,80 0,80 525 Vergleich 1 240 0,75 0,65 532 Vergleich A 39 0,85 0,70 528 Vergleich A 58 0,75 0,70 528 Vergleich A 87 0,70 0,70 528 Vergleich B 39 0,75 0,70 520 Vergleich B 58 0,65 0,65 520 Vergleich B 87 0,70 0,65 520 Vergleich The material is then subjected to sensitometric exposure behind a yellow and a purple filter. It is then developed in Agfa-Neutol developer and the gradation differentiation behind the two filters is determined as the exposure range in logarithmic units (logBU). The scope of exposure between the density densities D = 1.7 and D = 0.04 obtained is referred to as logBU. The results are summarized in Table 2, namely in

• Column 1: the green sensitizer used
• Column 2: the amount of green sensitizer in µmoles per mole of silver
• Column 3: logBU behind yellow filter
• Column 4: logBU behind purple filter
• Column 5: the sensitization maximum in nm.

Table 2 1 2nd 3rd 4th 5 3rd 39 1.30 0.65 527 invention 3rd 58 1.40 0.60 527 invention 3rd 87 1.40 0.60 527 invention 3rd 130 1.20 0.70 527 invention 5 87 1.20 0.75 545 invention 2nd 87 1.40 0.80 525 invention 1 39 1.40 0.70 532 invention 1 58 1.50 0.65 532 invention 1 87 1.50 0.65 532 invention 3rd 240 0.75 0.70 527 comparison 5 240 0.80 0.75 545 comparison 2nd 240 0.80 0.80 525 comparison 1 240 0.75 0.65 532 comparison A 39 0.85 0.70 528 comparison A 58 0.75 0.70 528 comparison A 87 0.70 0.70 528 comparison B 39 0.75 0.70 520 comparison B 58 0.65 0.65 520 comparison B 87 0.70 0.65 520 comparison

As can be seen in Table 2, the gradation differentiation when exposed behind yellow and purple filters in the green sensitizers according to the invention is very good and, within certain limits, is only slightly dependent on the amount of dye; while at higher amounts - in this emulsion example 240 µmol / mol of silver - and in the case of green sensitizers of constitution (A or B) not according to the invention, there is no differentiation.

Example 2

Example 2 is carried out analogously to Example 1, with an emulsion prepared according to the Kipp method Silver chloride bromide emulsion with 27 mol% bromide and 73 mol% chloride, grain size 0.30 μ, doped with 0.35 μmol RhCl₃ per mol Ag, is used. The results are shown in Table 3.

Table 3 shows that even with this emulsion with a high chloride content, a gradation differentiation is obtained with the green sensitizers according to the invention, while the comparison dyes have no differentiation. Table 3 1 2nd 3rd 4th 5 24th 75 1.10 0.60 555 invention 23 75 1.40 0.60 545 invention 21st 75 1.30 0.55 545 invention 20th 75 1.25 0.60 545 invention 7 75 1.25 0.70 530 invention 1 71 1.40 0.60 525 invention 1 89 1.35 0.60 525 invention 1 107 1.20 0.65 525 invention 2nd 75 1.50 0.70 525 invention 12 75 1.30 0.65 545 invention A 75 0.70 0.65 525 comparison B 75 0.75 0.70 520 comparison C. 71 0.65 0.60 520 comparison C. 107 0.60 0.60 520 comparison

Example 3

The silver chloride bromide emulsions according to Examples 1 and 2, designated Emulsion 1 and 2 in this example, are sensitized with the green sensitizers according to the invention shown in Table 4. However, the respective amount of dye is not added to the entire emulsion sample, but only the proportion (in%) indicated in column 6 of Table 4. The spectrally sensitized portion is digested for 20 minutes at 40 ° C and then added to the unsensitized rest of the emulsion sample. This is followed by watering and sensitometric testing as described in Example 1.

It can be seen from Table 4 that a particularly good gradation differentiation is obtained by the measure of only partial spectral sensitization of the emulsion with the dyes according to the invention. Table 4 1 2nd 3rd 4th 5 6 emulsion 7 150 1.50 0.65 530 50 2nd 11 75 1.30 0.75 545 50 2nd 12 150 1.35 0.60 545 50 2nd 26 75 1.30 0.80 545 50 2nd 27th 75 1.15 0.60 550 50 2nd 28 75 1.50 0.65 550 50 2nd 1 250 1.55 0.65 525 30th 2nd 1 150 1.45 0.65 525 50 2nd 3rd 172 1.60 0.70 527 50 1 1 261 1.50 0.70 532 33 1 1 174 1.50 0.70 532 50 1 1 116 1.40 0.70 532 75 1 24th 175 1.20 0.70 560 50 1 25th 175 1.20 0.80 520 50 1

Example 4

The emulsion samples according to Example 3 were repeated, but in each case 50% of the emulsion was green-sensitized according to the invention and 50% of the emulsion was sensitized in the blue spectral range by adding a blue sensitizer. The sprue and sensitometric test were carried out as described. The blue sensitivity increased the blue sensitivity behind the purple filter and in this way the sensitivity distance to the high green sensitivity that is achieved with the green sensitizers according to the invention was reduced.

• 1 den Grünsensibilisator
• 2 Menge an Grünsensibilisator in µMol pro Mol Ag
• 3 Blausensibilisator BS
• 4 Menge an Blausensibilisator in µMol pro Mol Ag
• 5 logBU hinter Gelbfilter
• 6 logBU hinter Purpurfilter
• 7 relative Empfindlichkeit hinter Purpurfilter.

Tabelle 5 Emulsion 2 aus Beispiel 3 1 2 3 4 5 6 7 1 89 - - 1,45 0,65 100 1 89 BS6 40 1,40 0,60 180 1 89 BS4 40 1,45 0,55 215 1 89 BS8 40 1,35 0,60 255 1 89 BS1 20 1,35 0,65 220 Tabelle 6 Emulsion 1 aus Beispiel 3 1 2 3 4 5 6 7 3 86 - - 1,60 0,70 100 3 86 BS6 90 1,55 0,70 170 3 86 BS4 90 1,50 0,75 160 3 86 BS1 75 1,45 0,70 195 The results of the samples are shown in Tables 5 and 6, namely in the columns

• 1 the green sensitizer
• 2 Amount of green sensitizer in µmol per mole Ag
• 3 Blue sensitizer BS
• 4 Amount of blue sensitizer in µmol per mole Ag
• 5 logBU behind yellow filter
• 6 logBU behind purple filter
• 7 Relative sensitivity behind the purple filter.

Table 5 Emulsion 2 from Example 3 1 2nd 3rd 4th 5 6 7 1 89 - - 1.45 0.65 100 1 89 BS6 40 1.40 0.60 180 1 89 BS4 40 1.45 0.55 215 1 89 BS8 40 1.35 0.60 255 1 89 BS1 20th 1.35 0.65 220 Emulsion 1 from Example 3 1 2nd 3rd 4th 5 6 7 3rd 86 - - 1.60 0.70 100 3rd 86 BS6 90 1.55 0.70 170 3rd 86 BS4 90 1.50 0.75 160 3rd 86 BS1 75 1.45 0.70 195

Claims (5)

1. Gradation-variable SW paper with a light-sensitive silver halide emulsion layer, characterized in that the silver halide with a compound of the formula

wherein
R₁ is hydrogen, halogen, alkyl, alkoxy,
R₂ alkyl, sulfoalkyl or carboxyalkyl
R₃ alkyl, hydroxyalkyl, acyloxyalkyl,
R₄ alkyl, sulfoalkyl or carboxylalkyl
R₅ halogen, cyan, aminocarbonyl, trifluoromethyl or alkoxyycarbonyl,
R₆ is hydrogen or R₅,
X ^⊖ an anion and
n is 0 or 1,
where at least one of the radicals R₁, R₅ and R₆ is halogen,
n is 0 if one of the radicals R₂ or R₄ is sulfoalkyl or carboxyalkyl, and n is 1 if none of the radicals R₂ and R₄ is sulfoalkyl or carboxyalkyl,

in a lot of

to

µMol / Mol

Silver halide is sensitized green, whereby d is the mean grain diameter of the silver halide in µm. 2. Gradation-variable SW paper according to claim 1, characterized in that only 20 to 80 wt .-% of the emulsion with a compound of formula (I) are sensitized green. 3. Gradation-variable SW paper according to claim 1, characterized in that the silver halide emulsion layer contains a mixture of 40 to 85 wt .-% according to claim 1 green-sensitized emulsion and 15 to 60 wt .-% blue-sensitized emulsion. 4. Gradation-variable SW paper according to claim 1, characterized in that the average grain size of the silver halide grains is 0.2 to 0.6 µm. 5. Gradation-variable SW paper according to claim 1, characterized in that the silver halide the silver halide emulsion layer is composed of 20 to 80 mol% AgBr, 80 to 20 mol% AgCl and 0 to 5 mol% AgI.