Photographic element containing specific magenta coupler

Disclosed is a photographic element comprising a support on which is coated at least one layer containing a light sensitive silver halide emulsion having associated therewith a dye-forming coupler of Formula (1a). wherein R.sub.1 is an alkyl group of not more than 8 carbon atoms; R.sub.5, R.sub.6, R.sub.7, and R.sub.8 each independently represent a hydrogen atom or a substituent; and A is an alkylene group. The element has improved post-process keeping.

FIELD OF THE INVENTION 
The present invention relates to a color photographic recording material, 
containing a particular pyrazolo[1,5-a]benzimidazole coupler having in the 
2-position an alkoxy group containing not more than 8 carbon atoms. 
BACKGROUND OF THE INVENTION 
Silver halide color photography depends on the formation of dyes in order 
to reproduce an image. These dyes are typically formed from couplers 
present in or adjacent to the light sensitive silver halide emulsion 
layers which react to image light upon exposure. During development, the 
latent image recorded by the silver halide emulsion is developed to 
amplify the image. During this process in which silver halide is reduced 
to elemental silver, the color developer compound used is at the same time 
oxidized, as is typical in a redox reaction. The oxidized developer then 
reacts or couples with the coupler compound present in or adjacent to the 
emulsion layer to form a dye of the desired color. 
Typically, a silver halide emulsion layer containing a magenta dye-forming 
coupler is sensitized to green light. This facilitates so-called 
negative-positive processing in which the image is initially captured in a 
negative format where black is captured as white, white as black, and the 
colors as their complimentary colors (e.g., green as magenta, blue as 
yellow, and red as cyan). Then the initial image can be optically printed 
in the correct colors on a reflective or transparent background through 
the device of optical printing which has the effect of producing a 
negative of the negative, or a positive image of the original scene. 
Viewable images may also be produced through reversal processing in which 
the initial negative image is reversed by using a black and white 
developer, processed to remove the developed silver but leaving the 
undeveloped silver halide, and by then fogging the element in the presence 
of color developer to provide developed silver in inverse proportion to 
the amount of image light with corresponding dye formation. 
For incorporation into a photographic element, the couplers are typically 
dissolved in high-boiling organic solvents known as "coupler solvents," 
and dispersed in gelatin with the aid of surfactants. 
One of the difficulties with color couplers is achieving a desirable 
combination of physical and chemical properties of the coupler and the dye 
formed from it. For instance, the coupler should have good solubility in 
the coupler solvent, good dispersibility in gelatin, and high dye-forming 
activity. It should also have a high degree of resistance to decomposition 
due to light, heat and humidity, which can cause stains. The image dye 
should have the proper hue and a high degree of resistance to fading or 
hue changes due to light, heat and humidity. 
Couplers that form magenta dyes upon reaction with oxidized color 
developing agent are described in such representative patents and 
publications as: U.S. Pat. Nos. 2,311,082, 2,343,703, 2,369,489, 
2,600,788, 2,908,573, 3,062,653, 3,152,896, 3,519,529, 3,758,309, and 
4,540,654; and "Farbkupplereine Literature Ubersicht," published in Agfa 
Mitteilungen, Band III, pp. 126-156 (1961). Typically, such couplers are 
pyrazolones and pyrazoloazoles, especially pyrazolo[2,3-b][1,2,4]triazoles 
described by Formula (A) and pyrazolo[3,2-c][1,2,4]triazoles described by 
Formula (B). 
##STR1## 
In Formulas (A) and (B), R and R.sub.2 represent substituents and Z is a 
hydrogen atom or a group capable of being split off during the coupling 
reaction. Typically, R.sub.2 is an alkyl group. An alkoxy group in this 
position leads to image dyes with very poor light stability. 
The present invention is concerned with the pyrazolo[1,5-a]benzimidazole 
type of magenta dye-forming couplers (hereafter referred to as PBI 
couplers). These couplers may be described by Formula (1) 
##STR2## 
in which R.sub.2 and R.sub.5 -R.sub.8 represent hydrogen or substituents 
and Z represents hydrogen or a group capable of being split off during the 
coupling reaction. 
German patent 1,070,030 discloses PBI couplers which form magenta dyes upon 
coupling. In the examples given, R.sub.2 represents an alkyl or phenyl 
group. Couplers of these types are known to have poor coupling reactivity 
and to yield image dyes whose absorption spectra are too bathochromic for 
practical use in color photographic papers, and which have poor stability 
to light. International Patent Application WO 91/14970 describes PBI 
couplers with specifically substituted alkylthio coupling-off groups, 
including carboxyalkylthio groups. Such couplers offer marked improvements 
in coupling reactivity but do not offer improved dye hue or light 
stability. U.S. Pat. No. 5,143,821 describes PBI couplers in which R.sub.2 
represents an alkoxy group. Such couplers are advantageous because they 
have much better coupling reactivity than those in which R.sub.2 
represents an alkyl group and because the image dyes formed from them have 
good spectral absorption characteristics. Moreover, the dyes from these 
couplers have better light stability than the dyes from PBI couplers in 
which R.sub.2 is an alkyl group. 
However, most PBI couplers are unstable to heat and humidity and have a 
high propensity to generate yellow stains during post-process keeping, 
known in the art as "yellowing." 
A problem to be solved is to provide a dye-forming photographic element 
that resists formation of stains during keeping after processing or, in 
other words, an element that exhibits improved post-process keeping. 
SUMMARY OF THE INVENTION 
The invention provides a photographic element comprising a support on which 
is coated at least one layer containing a light sensitive silver halide 
emulsion having associated therewith a dye-forming coupler of Formula 
(1a). 
##STR3## 
wherein R.sub.1 is an alkyl group of not more than 8 carbon atoms; 
R.sub.5, R.sub.6, R.sub.7, and R.sub.8 each independently represent a 
hydrogen atom or a substituent; and A is an alkylene group. 
The invention also includes a method of forming an image in the element of 
the invention. 
The element exhibits improved post-process keeping. 
DETAILED DESCRIPTION OF THE INVENTION 
The various substituents of formula (1a) are more particularly described as 
follows: 
R.sub.1 is an alkyl group of not more than 8 carbon atoms that may be 
linear, branched or cyclic; saturated or unsaturated; substituted or 
unsubstituted. Suitably, R.sub.1 contains up to 5 carbon atoms and may 
desirably, R.sub.1 contain a secondary or tertiary alkyl group of up to 5 
carbon atoms. 
R.sub.5, R.sub.6, R.sub.7, and R.sub.8 are each independently a hydrogen 
atom or a substituent. Typically, at least three of R.sub.5, R.sub.6, 
R.sub.7, and R.sub.8 are hydrogen atoms. 5 A is an alkylene group which 
may be straight or branched. Preferably, A has 1 to 3 carbon atoms. 
Suitably, A is an ethylene group. The following examples further 
illustrate the coupler of the invention. It is not to be construed that 
the present invention is limited to these examples. 
##STR4## 
The couplers of the invention can be made in ways well-known in the art 
such as described in U.S. Pat. No. 5,143,821. 
A suitable stabilizer compound to be incorporated in association with the 
coupler of the invention is represented by Formula (ST-I): 
##STR5## 
wherein R.sub.b is a substituent, n is an integer from 0 to 4, R.sub.d and 
R.sub.e are each hydrogen atoms or alkyl groups, and any of the groups 
R.sub.b, R.sub.d and R.sub.e may be joined together to form a ring. 
In Formula (ST-I), R.sub.b is suitably an alkyl group, an alkoxy group, a 
primary or secondary amino group, or an amido group. 
In Formula (ST-I), n is an integer from 0 to 4 and preferably n is 0. 
In Formula (ST-I), R.sub.d and R.sub.e are each independently a hydrogen 
atom or an alkyl group which may be linear or branched, saturated or 
unsaturated, substituted or unsubstituted, with the provision that R.sub.d 
and R.sub.e cannot both represent hydrogen groups. Any of the groups 
R.sub.b, R.sub.d and R.sub.e may be joined to form a ring. 
Desirably, the compound is ballasted so as not to diffuse from the element 
during processing and suitably contains at least 8 aliphatic carbon atoms. 
One embodiment is a stabilizer represented by Formula (ST-II): 
##STR6## 
wherein R.sub.3 represents an aryl group or a heterocyclic group; Z.sub.1 
and Z.sub.2 independently represent an alkylene group having 1 to 3 carbon 
atoms provided that the total number of carbon atoms in the ring is 3 to 
6; and q is an integer of 1 or 2. 
Another embodiment is represented by Formula (ST-III): 
##STR7## 
wherein R.sub.a is an alkyl group which may be linear or branched, 
saturated or unsaturated, substituted or unsubstituted, R.sub.b is a 
substituent, n is an integer from 0 to 4, R.sub.d and R.sub.e are each 
hydrogen atoms or alkyl groups, and any of the groups R.sub.b, R.sub.d and 
R.sub.e may be joined together to form a ring. 
A particular embodiment is represented by Formula (ST-IV): 
##STR8## 
The following examples further illustrate this type of stabilizer. It is 
not to be construed that the present invention is limited to these 
examples. 
##STR9## 
Also useful are co-stabilizers of the bisphenol type and the phenolic type 
as described by formulas R and I in U.S. Pat. No. 5,561,037. In addition 
to the post-processing keeping advantages, the element of the invention 
provides other suitable photographic properties such as reactivity, speed, 
density, gamma, light stability, raw stock keeping, and dye hue. 
Unless otherwise specifically stated, the term substituted or substituent 
means any group or atom other than hydrogen bonded to the remainder of a 
molecule. Additionally, when the term "group" is used, it means that when 
a substituent group contains a substitutable hydrogen, it is also intended 
to encompass not only the substituent's unsubstituted form, but also its 
form further substituted with any substituent group or groups as herein 
mentioned, so long as the substituent does not destroy properties 
necessary for photographic utility. Suitably, a substituent 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 or cyclic 
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-dodecyloxyethoxy; aryl such as 
phenyl, 4-t-butylphenyl, 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-pentyl-phenoxy)acetamido, 
alpha-(2,4-di-t-pentylphenoxy)butyramido, 
alpha-(3-pentadecylphenoxy)-hexanamido, 
alpha-(4-hydroxy-3-t-butylphenoxy)-tetradecanamido, 2-oxo-pyrrolidin-1-yl, 
2-oxo-5-tetradecylpyrrolin-1-yl, N-methyltetradecanamido, N-succinimido, 
N-phthalimido, 2,5-dioxo-1-oxazolidinyl, 3-dodecyl-2,5-dioxo-1-imidazolyl, 
and N-acetyl-N-dodecylamino, ethoxycarbonylamino, phenoxycarbonylamino, 
benzyloxycarbonylamino, hexadecyloxycarbonylamino, 
2,4-di-t-butylphenoxycarbonylamino, phenylcarbonylamino, 
2,5-(di-t-pentylphenyl)carbonylamino, p-dodecyl-phenylcarbonylamino, 
p-tolylcarbonylamino, N-methylureido, N,N-dimethylureido, 
N-methyl-N-dodecylureido, N-hexadecylureido, N,N-dioctadecylureido, 
N,N-dioctyl-N'-ethylureido, N-phenylureido, N,N-diphenylureido, 
N-phenyl-N-p-tolylureido, N-(m-hexadecylphenyl)ureido, 
N,N-(2,5-di-t-pentylphenyl)-N'-ethylureido, and t-butylcarbonamido; 
sulfonamido, such as methylsulfonamido, benzenesulfonamido, 
p-tolylsulfonamido, p-dodecylbenzenesulfonamido, 
N-methyltetradecylsulfonamido, N,N-dipropyl-sulfamoylamino, and 
hexadecylsulfonamido; sulfamoyl, such as N-methylsulfamoyl, 
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-dibutylcarbamoyl, N-octadecylcarbamoyl, 
N-[4-(2,4-di-t-pentylphenoxy)butyl]carbamoyl, 
N-methyl-N-tetradecylcarbamoyl, and N,N-dioctylcarbamoyl; acyl, such as 
acetyl, (2,4-di-t-amylphenoxy)acetyl, phenoxycarbonyl, 
p-dodecyloxyphenoxycarbonyl methoxycarbonyl, butoxycarbonyl, 
tetradecyloxycarbonyl, ethoxycarbonyl, benzyloxycarbonyl, 
3-pentadecyloxycarbonyl, and dodecyloxycarbonyl; sulfonyl, such as 
methoxysulfonyl, octyloxysulfonyl, tetradecyloxysulfonyl, 
2-ethylhexyloxysulfonyl, phenoxysulfonyl, 2,4-di-t-pentylphenoxysulfonyl, 
methylsulfonyl, octylsulfonyl, 2-ethylhexylsulfonyl, dodecylsulfonyl, 
hexadecylsulfonyl, phenylsulfonyl, 4-nonylphenylsulfonyl, and 
p-tolylsulfonyl; sulfonyloxy, such as dodecylsulfonyloxy, and 
hexadecylsulfonyloxy; sulfinyl, such as methylsulfinyl, octylsulfinyl, 
2-ethylhexylsulfinyl, dodecylsulfinyl, hexadecylsulfinyl, phenylsulfinyl, 
4-nonylphenylsulfinyl, and p-tolylsulfinyl; thio, such as ethylthio, 
octylthio, benzylthio, tetradecylthio, 
2-(2,4-di-t-pentylphenoxy)ethylthio, phenylthio, 
2-butoxy-5-t-octylphenylthio, and p-tolylthio; acyloxy, such as acetyloxy, 
benzoyloxy, octadecanoyloxy, p-dodecylamidobenzoyloxy, 
N-phenylcarbamoyloxy, N-ethylcarbamoyloxy, and cyclohexylcarbonyloxy; 
amine, such as phenylanilino, 2-chloroanilino, diethylamine, dodecylamine; 
imino, such as 1 (N-phenylmido)ethyl, N-succinimido or 
3-benzylhydantoinyl; 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, etc. 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. 
The materials of the invention can be used in any of the ways and in any of 
the combinations known in the art. Typically, the invention 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, 
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 color 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. 
To control the migration of various components, it may be desirable to 
include a high molecular weight hydrophobe or "ballast" group in the 
component molecule. Representative ballast groups include substituted or 
unsubstituted alkyl or aryl groups containing 8 to 40 carbon atoms. 
Representative substituents on such groups include alkyl, aryl, alkoxy, 
aryloxy, alkylthio, hydroxy, halogen, alkoxycarbonyl, aryloxcarbonyl, 
carboxy, acyl, acyloxy, amino, anilino, carbonamido, carbamoyl, 
alkylsulfonyl, arysulfonyl, sulfonamido, and sulfamoyl groups wherein the 
substituents typically contain 1 to 40 carbon atoms. Such substituents can 
also be further substituted. 
The photographic elements can be single color elements or multicolor 
elements. Multicolor 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. In 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 multicolor 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 contain additional layers, such as filter layers, 
interlayers, overcoat layers, subbing layers, and the like. 
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, or as described 
in Hatsumi Kyoukai Koukai Gihou No. 94-6023, published Mar. 15, 1994, 
available from the Japanese Patent Office, the contents of which are 
incorporated herein by reference. 
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 1996, Item 38957, 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. 
The silver halide emulsions employed in the elements of this invention can 
be either negative-working or positive-working. Suitable emulsions hand 
their preparation as well as methods of chemical and spectral 
sensitization are described in Sections I through V. 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 VIII. Color 
materials are described in Sections X through XIII. Suitable methods for 
incorporating couplers and dyes, including dispersions in organic 
solvents, are described in Section X(E). Scan facilitating is described in 
Section XIV. Supports, exposure, development systems, and processing 
methods and agents are described in Sections XV to XX. Certain desirable 
photographic elements and processing steps are described in Research 
Disclosure, Item 37038, February 1995. 
Coupling-off groups are well known in the art. Such groups can determine 
the chemical equivalency of a coupler, i.e., whether it is a 2-equivalent 
or a 4-equivalent coupler, or 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, color correction and the like. 
The presence of hydrogen at the coupling site provides a 4-equivalent 
coupler, and the presence of another coupling-off group usually provides a 
2-equivalent coupler. Representative classes of such coupling-off groups 
include, for example, chloro, alkoxy, aryloxy, hetero-oxy, sulfonyloxy, 
acyloxy, acyl, heterocyclyl such as oxazolidinyl or hydantoinyl, 
sulfonamido, mercaptotetrazole, benzothiazole, mercaptopropionic acid, 
phosphonyloxy, arylthio, and arylazo. These coupling-off groups are 
described in the art, for example, in U.S. Pat. Nos. 2,455,169, 3,227,551, 
3,432,521, 3,476,563, 3,617,291, 3,880,661, 4,052,212 and 4,134,766; and 
in U.K. Patents and published application Nos. 1,466,728, 1,531,927, 
1,533,039, 2,006,755A and 2,017,704A, the disclosures of which are 
incorporated herein by reference. 
Image dye-forming couplers may be included in the element such as couplers 
that form cyan dyes upon reaction with oxidized color developing agents 
which are described in such representative patents and publications as: 
"Farbkuppler-eine Literature Ubersicht," published in Agfa Mitteilungen, 
Band III, pp. 156-175 (1961) as well as in U.S. Pat. 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; 4,746,602; 4,753,871; 4,770,988; 4,775,616; 
4,818,667; 4,818,672; 4,822,729; 4,839,267; 4,840,883; 4,849,328; 
4,865,961; 4,873,183; 4,883,746; 4,900,656; 4,904,575; 4,916,051; 
4,921,783; 4,923,791; 4,950,585; 4,971,898; 4,990,436; 4,996,139; 
5,008,180; 5,015,565; 5,011,765; 5,011,766; 5,017,467; 5,045,442; 
5,051,347; 5,061,613; 5,071,737; 5,075,207; 5,091,297; 5,094,938; 
5,104,783; 5,178,993; 5,813,729; 5,187,057; 5,192,651; 5,200,305; 
5,202,224; 5,206,130; 5,208,141; 5,210,011; 5,215,871; 5,223,386; 
5,227,287; 5,256,526; 5,258,270; 5,272,051; 5,306,610; 5,326,682; 
5,366,856; 5,378,596; 5,380,638; 5,382,502; 5,384,236; 5,397,691; 
5,415,990; 5,434,034; 5,441,863; EPO 0 246 616; EPO 0 250 201; EPO 0 271 
323; EPO 0 295 632; EPO 0 307 927; EPO 0 333 185; EPO 0 378 898; EPO 0 389 
817; EPO 0 487 111; EPO 0 488 248; EPO 0 539 034; EPO 0 545 300; EPO 0 556 
700; EPO 0 556 777; EPO 0 556 858; EPO 0 569 979; EPO 0 608 133; EPO 0 636 
936; EPO 0 651 286; EPO 0 690 344; German OLS 4,026,903; German OLS 
3,624,777. and German OLS 3,823,049. Typically such couplers are phenols, 
naphthols, or pyrazoloazoles. 
Couplers that form magenta dyes upon reaction with oxidized color 
developing agent are described in such representative patents and 
publications as: "Farbkuppler-eine Literature Ubersicht," published in 
Agfa Mitteilungen, Band III, pp. 126-156 (1961) as well as U.S. Pat. Nos. 
2,311,082 and 2,369,489; 2,343,701; 2,600,788; 2,908,573; 3,062,653; 
3,152,896; 3,519,429; 3,758,309; 3,935,015; 4,540,654; 4,745,052; 
4,762,775; 4,791,052; 4,812,576; 4,835,094; 4,840,877; 4,845,022; 
4,853,319; 4,868,099; 4,865,960; 4,871,652; 4,876,182; 4,892,805; 
4,900,657; 4,910,124; 4,914,013; 4,921,968; 4,929,540; 4,933,465; 
4,942,116; 4,942,117; 4,942,118; 4,959,480; 4,968,594; 4,988,614; 
4,992,361; 5,002,864; 5,021,325; 5,066,575; 5,068,171; 5,071,739; 
5,100,772; 5,110,942; 5,116,990; 5,118,812; 5,134,059; 5,155,016; 
5,183,728; 5,234,805; 5,235,058; 5,250,400; 5,254,446; 5,262,292; 
5,300,407; 5,302,496; 5,336,593; 5,350,667; 5,395,968; 5,354,826; 
5,358,829; 5,368,998; 5,378,587; 5,409,808; 5,411,841; 5,418,123; 
5,424,179; EPO 0 257 854; EPO 0 284 240; EPO 0 341 204; EPO 347,235; EPO 
365,252; EPO 0 422 595; EPO 0 428 899; EPO 0 428 902; EPO 0459 331; EPO 
0467 327; EPO 0476 949; EPO 0487 081; EPO 0489 333; EPO0 512304; EPO 0515 
128; EPO 0534703; EPO0 554778; EPO0 558 145; EPO 0 571 959; EPO 0 583 832; 
EPO 0 583 834; EPO 0 584 793; EPO 0 602 748; EPO 0 602 749; EPO 0 605 918; 
EPO 0 622 672; EPO 0 622 673; EPO 0 629 912; EPO 0 646 841, EPO 0 656 561; 
EPO 0 660 177; EPO 0 686 872; WO 90/10253; WO 92/09010; WO 92/10788; WO 
92/12464; WO 93/01523; WO 93/02392; WO 93/02393; WO 93/07534; UK 
Application 2,244,053; Japanese Application 03192-350; German OLS 
3,624,103; German OLS 3,912,265; and German OLS 40 08 067. Typically such 
couplers are pyrazolones, pyrazoloazoles, or pyrazolobenzimidazoles that 
form magenta dyes upon reaction with oxidized color developing agents. 
Couplers that form yellow dyes upon reaction with oxidized color developing 
agent are described in such representative patents and publications as: 
"Farbkuppler-eine Literature Ubersicht," published in Agfa Mitteilungen; 
Band III; pp. 112-126 (1961); as well as U.S. Pat. No. 2,298,443; 
2,407,210; 2,875,057; 3,048,194; 3,265,506; 3,447,928; 4,022,620; 
4,443,536; 4,758,501; 4,791,050; 4,824,771; 4,824,773; 4,855,222; 
4,978,605; 4,992,360; 4,994,361; 5,021,333; 5,053,325; 5,066,574; 
5,066,576; 5,100,773; 5,118,599; 5,143,823; 5,187,055; 5,190,848; 
5,213,958; 5,215,877; 5,215,878; 5,217,857; 5,219,716; 5,238,803; 
5,283,166; 5,294,531; 5,306,609; 5,328,818; 5,336,591; 5,338,654; 
5,358,835; 5,358,838; 5,360,713; 5,362,617; 5,382,506; 5,389,504; 
5,399,474;. 5,405,737; 5,411,848; 5,427,898; EPO 0 327 976; EPO 0 296 793; 
EPO 0 365 282; EPO 0 379 309; EPO 0 415 375; EPO 0 437 818; EPO 0 447 969; 
EPO 0 542 463; EPO 0 568 037; EPO 0 568 196; EPO 0 568 777; EPO 0 570 006; 
EPO 0 573 761; EPO 0 608 956; EPO 0 608 957; and EPO 0 628 865. Such 
couplers are typically open chain ketomethylene compounds. 
Couplers that form colorless products upon reaction with oxidized color 
developing agent are described in such representative patents as: U.K. 
Patent No. 861,138; U.S. Pat. Nos. 3,632,345, 3,928,041, 3,958,993 and 
3,961,959. Typically such couplers are cyclic carbonyl containing 
compounds that form colorless products on reaction with an oxidized color 
developing agent. 
Couplers that form black dyes upon reaction with oxidized color developing 
agent are described in such representative patents as U.S. Pat. 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 color developing agent. 
It may be useful to use a combination of couplers any of which may contain 
known ballasts or coupling-off groups such as those described in U.S. Pat. 
Nos. 4,301,235; 4,853,319 and 4,351,897. The coupler may contain 
solubilizing groups such as described in U.S. Pat. No. 4,482,629. 
Typically, couplers are incorporated in a silver halide emulsion layer in a 
mole ratio to silver of 0.1 to 1.0 and generally 0.1 to 0.5. Usually the 
couplers are dispersed in a high-boiling organic solvent in a weight ratio 
of solvent to coupler of 0.1 to 10.0, typically 0.1 to 2.0 and usually 0.1 
to 0.6, although direct dispersions are sometimes employed. 
The invention materials may also 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 193,389; EP 301,477; U.S. Pat. Nos. 
4,163,669; 4,865,956; and 4,923,784, may be useful. Also contemplated is 
use of the compositions in association with nucleating agents, development 
accelerators or their precursors (UK Patent 2,097,140; U.K. Patent 
2,131,188); electron transfer agents (U.S. Pat. Nos. 4,859,578; 
4,912,025); antifogging and anti color-mixing agents such as derivatives 
of hydroquinones, aminophenols, amines, gallic acid; catechol; ascorbic 
acid; hydrazides; sulfonamidophenols; and non color-forming couplers. 
It is contemplated that the concepts of the present invention may be 
employed to obtain reflection color 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 of the 
invention may be coated on pH adjusted support as described in U.S. Pat. 
No. 4,917,994; on a support with reduced oxygen permeability (EP 553,339); 
with epoxy solvents (EP 164,961); with nickel complex stabilizers (U.S. 
Pat. Nos. 4,346,165; 4,540,653 and 4,906,559 for example); with ballasted 
chelating agents such as those in U.S. Pat. No. 4,994,359 to reduce 
sensitivity to polyvalent cations such as calcium; and with stain reducing 
compounds such as described in U.S. Pat. No. 5,068,171. Other compounds 
useful in combination with 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; 
83-09,959. 
Conventional radiation-sensitive silver halide emulsions can be employed in 
the practice of this invention. Such emulsions are illustrated by Research 
Disclosure, Item 38755, September 1996, I. Emulsion grains and their 
preparation. 
Especially useful in this invention are tabular grain silver halide 
emulsions. Tabular grains are those having two parallel major crystal 
faces and having an aspect ratio of at least 2. The term "aspect ratio" is 
the ratio of the equivalent circular diameter (ECD) of a grain major face 
divided by its thickness (t). Tabular grain emulsions are those in which 
the tabular grains account for at least 50 percent (preferably at least 70 
percent and optimally at least 90 percent) of the total grain projected 
area. Preferred tabular grain emulsions are those in which the average 
thickness of the tabular grains is less than 0.3 micrometer (preferably 
thin--that is, less than 0.2 micrometer and most preferably 
ultrathin--that is, less than 0.07 micrometer). The major faces of the 
tabular grains can lie in either {111} or {100} crystal planes. The mean 
ECD of tabular grain emulsions rarely exceeds 10 micrometers and more 
typically is less than 5 micrometers. 
In their most widely used form tabular grain emulsions are high bromide 
{111} tabular grain emulsions. Such emulsions are illustrated by Kofron et 
al U.S. Pat. No. 4,439,520, Wilgus et al U.S. Pat. No. 4,434,226, Solberg 
et al U.S. Pat. No. 4,433,048, Maskasky U.S. Pat. Nos. 4,435,501, 
4,463,087 and 4,173,320, Daubendiek et al U.S. Pat. Nos. 4,414,310 and 
4,914,014, Sowinski et al U.S. Pat. No. 4,656,122, Piggin et al U.S. Pat. 
Nos. 5,061,616 and 5,061,609, Tsaur et al U.S. Pat. Nos. 5,147,771, '772, 
'773, 5,171,659 and 5,252,453, Black et al 5,219,720 and 5,334,495, Delton 
U.S. Pat. Nos. 5,310,644, 5,372,927 and 5,460,934, Wen U.S. Pat. No. 
5,470,698, Fenton et al U.S. Pat. No. 5,476,760, Eshelman et al U.S. Pat. 
Nos. 5,612,,175 and 5,614,359, and Irving et al U.S. Pat. No. 5,667,954. 
Ultrathin high bromide {111} tabular grain emulsions are illustrated by 
Daubendiek et al U.S. Pat. Nos. 4,672,027, 4,693,964, 5,494,789, 5,503,971 
and 5,576,168, Antoniades et al U.S. Pat. No. 5,250,403, Olm et al U.S. 
Pat. No. 5,503,970, Deaton et al U.S. Pat. No. 5,582,965, and Maskasky 
U.S. Pat. No. 5,667,955. 
High bromide {100} tabular grain emulsions are illustrated by Mignot U.S. 
Pat. Nos. 4,386,156 and 5,386,156. 
High chloride {111} tabular grain emulsions are illustrated by Wey U.S. 
Pat. No. 4,399,215, Wey et al U.S. Pat. No. 4,414,306, Maskasky U.S. Pat. 
Nos. 4,400,463, 4,713,323, 5,061,617, 5,178,997, 5,183,732, 5,185,239, 
5,399,478 and 5,411,852, and Maskasky et al U.S. Pat. Nos. 5,176,992 and 
5,178,998. Ultrathin high chloride {111} tabular grain emulsions are 
illustrated by Maskasky U.S. Pat. Nos. 5,271,858 and 5,389,509. 
High chloride {100} tabular grain emulsions are illustrated by Maskasky 
U.S. Pat. Nos. 5,264,337, 5,292,632, 5,275,930 and 5,399,477, House et al 
U.S. Pat. No. 5,320,938, Brust et al U.S. Pat. No. 5,314,798, Szajewski et 
al U.S. Pat. No. 5,356,764, Chang et al U.S. Pat. Nos. 5,413,904 and 
5,663,041, Oyamada U.S. Pat. No. 5,593,821, Yamashita et al U.S. Pat. Nos. 
5,641,620 and 5,652,088, Saitou et al U.S. Pat. No. 5,652,089, and Oyamada 
et al U.S. Pat. No. 5,665,530. Ultrathin high chloride {100} tabular grain 
emulsions can be prepared by nucleation in the presence of iodide, 
following the teaching of House et al and Chang et al, cited above. 
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. Tabular grain emulsions of the 
latter type are illustrated by Evans et al. U.S. Pat. No. 4,504,570. 
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 color developing 
agent to reduce developable silver halide and oxidize the color developing 
agent. Oxidized color developing agent in turn reacts with the coupler to 
yield a dye. If desired "Redox Amplification" as described in Research 
Disclosure XVIII-B(5) may be used. 
With negative-working silver halide, the processing step described above 
provides a negative image. One type of such element, referred to as a 
color negative film, is designed for image capture. Speed (the sensitivity 
of the element to low light conditions) is usually critical to obtaining 
sufficient image in such elements. Such elements are typically silver 
bromoiodide emulsions and may be processed, for example, in known color 
negative processes such as the Kodak C-41 process as described in The 
British Journal of Photography Annual of 1988, pages 191-198. If a color 
negative film element is to be subsequently employed to generate a 
viewable projection print as for a motion picture, a process such as the 
Kodak ECN-2 process described in the H-24 Manual available from Eastman 
Kodak Co. may be employed to provide the color negative image on a 
transparent support. Color negative development times are typically 3'15" 
or less and desirably 90 or even 60 seconds or less. 
Another type of color negative element is a color print. Such an element is 
designed to receive an image optically printed from an image capture color 
negative element. A color print element may be provided on a reflective 
support for reflective viewing (e.g. a snap shot) or on a transparent 
support for projection viewing as in a motion picture. Elements destined 
for color reflection prints are provided on a reflective support, 
typically paper, employ silver chloride emulsions, and may be optically 
printed using the so-called negative-positive process where the element is 
exposed to light through a color negative film which has been processed as 
described above. The print may then be processed to form a positive 
reflection image using, for example, the Kodak RA-4 process as generally 
described in PCT WO 87/04534 or U.S. Pat. No. 4,975,357. Color projection 
prints may be processed, for example, in accordance with the Kodak ECP-2 
process as described in the H-24 Manual. Similarly, back-lit image 
transparencies may be prepared for display purposes. Color print 
development times are typically 90 seconds or less and desirably 45 or 
even 30 seconds or less. 
The above emulsions are typically sold with instructions to process using 
the appropriate method such as the mentioned color negative (Kodak C-41), 
color print (Kodak RA-4), or reversal (Kodak E-6) process. 
Preferred color 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-methanesulfonamido-ethyl)aniline 
sesquisulfate hydrate, 
4-amino-3-methyl-N-ethyl-N-(2-hydroxyethyl)aniline sulfate, 
4-amino-3-(2-methanesulfonamido-ethyl)-N,N-diethylaniline hydrochloride and 
4-amino-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 entire contents of the patents and other publications cited in this 
specification are incorporated herein by reference.

PHOTOGRAPHIC EXAMPLES 
Preparation of Photographic Elements 
Coupler M-1, stabilizers ST-I and ST-B, and coupler solvents dibutyl 
phthalate and bis(2-ethylhexyl)phthalate were dispersed in aqueous gelatin 
in the following manner: 
Coupler M-1 (0.312 g, 0.98 mmol), stabilizer ST-1 (0.286 g, 0.84 mmol), and 
stabilizer ST-B (0.286 g, 0.75 mmol) were dissolved in a mixture of 
dibutyl phthalate (0.429 g), bis(2-ethylhexyl) phthalate (0.429 g) and 
ethyl acetate (0.937 g). The mixture was heated to effect solution. After 
adding aqueous gelatin (21.93 g, 11.5%) and diisopropylnaphthalene 
sulfonic acid (sodium salt) (2.51 g 10% solution), the mixture was 
dispersed passing it three times through a Gaulin homogenizer. This 
dispersion was used in the preparation of the photographic element 101. 
Dispersions containing the couplers shown for elements 102-112 in Table 1 
were prepared in a similar manner. The amount of coupler in each 
dispersion was 0.98 mmol. (per square meter), and the amounts of 
stabilizers and solvents were the same as in element 101. 
On a gel-subbed, polyethylene-coated paper support were coated the 
following (per square meter): 
First Layer 
An underlayer containing 3.23 grams gelatin. 
Second Layer 
A photosensitive layer containing (per square meter) 2.15 grams total 
gelatin, an amount of green-sensitized silver chloride emulsion containing 
0.172 grams silver; the dispersion containing 6.1.times.10.sup.-4 mole of 
the coupler indicated in Table 1; and 0.043 gram surfactant Alkanol XC 
(trademark of E. I. Dupont Co.) (in addition to the Alkanol XC used to 
prepare the coupler dispersion 
Third Layer 
A protective layer containing 1.40 grams gelatin, 0.15 gram 
bis(vinylsulfonyl)methyl ether, 0.043 gram Alkanol XC, and 
4.40.times.10.sup.-6 gram tetraethylammonium perfluorooctanesulfonate. 
TABLE 1 
______________________________________ 
Comparison or 
Element Invention 
Coupler 
______________________________________ 
101 Invention 
M-1 
102 Invention 
M-3 
103 Invention 
M-4 
104 Invention 
M-5 
105 Invention 
M-6 
106 Invention 
M-7 
107 Invention 
M-8 
108 Invention 
M-9 
109 Invention 
M-10 
110 Comparison 
CM-1 
111 Comparison 
CM-2 
112 Comparison 
CM-3 
______________________________________ 
##STR10## CM-1 
##STR11## CM-2 
##STR12## CM-3 
##STR13## ST-1 
##STR14## ST-B 
Processed samples were prepared by exposing the coatings through a step 
wedge and processing as follows: 
______________________________________ 
Process Step Time (min.) 
Temp. (.degree. C.) 
______________________________________ 
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 per liter of solution): 
______________________________________ 
Developer 
Triethanolamine 
12.41 g 
Blankophor REU (trademark of Mobay Corp.) 
g 2.30 
Lithium polystyrene sulfonate 
g 0.09 
N,N-Diethylhydroxylamine 
g 4.59 
Lithium sulfate g 2.70 
Developing agent Dev-1 g 5.00 
1-Hydroxyethyl-1,1-diphosphonic acid 
g 0.49 
Potassium carbonate, anhydrous 
g 21.16 
Potassium chloride g 1.60 
Potassium bromide mg 7.00 
pH adjusted to 10.4 at 26.7.degree. C. 
Bleach-Fix 
Solution of ammonium thiosulfate 
g 71.85 
Ammonium sulfite g 5.10 
Sodium metabisulfite g 10.00 
Acetic acid g 10.20 
Ammonium ferric ethylenediaminetetra acetate 
48.58 
g 
Ethylenediaminetetraacetic acid 
g 3.86 
pH adjusted to 6.7 at 26.7.degree. C. 
______________________________________ 
Dev-1 
##STR15## 
The density to blue light of an unexposed area of each processed strip was 
measured. The strips were then incubated for four weeks at a temperature 
of 75.degree. C. and a relative humidity of 50%, and the density to blue 
light was reread. The increase in density during incubation was recorded 
as "yellowing" of the white area and is shown in Table 2. 
TABLE 2 
______________________________________ 
Example Element Comp/Inv Coup Yellowing 
______________________________________ 
1 101 Inv. M-1 0.02 
2 102 Inv. M-3 0.03 
3 103 Inv. M-4 0.04 
4 104 Inv. M-5 0.04 
5 105 Inv. M-6 0.03 
6 106 Inv. M-7 0.04 
7 107 Inv. M-8 0.10 
8 108 Inv. M-9 0.05 
9 109 Inv. M-10 0.14 
10 110 Comp. CM-1 0.32 
11 111 Comp. CM-2 0.29 
12 112 Comp. CM-3 0.29 
______________________________________ 
The data clearly demonstrate that the couplers of the invention exhibit 
very low yellowing, while the comparison couplers exhibit unacceptably 
high yellowing. Images that are stored in comparative elements under hot 
and humid conditions such as those that exist in many parts of the world 
will turn yellow much more quickly than those of the invention.