Low staining green spectral sensitizing dyes and silver chloride emulsions containing iodide

The invention relates to a photographic element comprising a silver halide emulsion wherein at least one layer contains a silver chloroiodide emulsion containing at least 95 mole percent chloride and contains a sensitizing dye of the following general formula (I): ##STR1## wherein: Z1 represents a halogen, a cyano group, an amide substituted aromatic group, or a heteroaromatic group that is directly appended to the benzene ring shown or an aromatic group that is attached through an amide linking group and PA1 Z2 represents a substituted or unsubstituted alkyl group, substituted or unsubstituted alkoxy group, cyano group, a substituted or unsubstituted amide group, a substituted or unsubstituted carbamoyl group, halogen, an amide substituted aromatic group, or a heteroaromatic group that is directly appended to the benzene ring shown or an aromatic group that is attached through an amide linking group and PA1 W1 is one or more ions as needed to balance the charge on the molecule and PA1 R1 and R2 are, independently, substituted or unsubstituted alkyl group and PA1 R3 is H or a substituted or unsubstituted lower alkyl group or a substituted or unsubstituted aryl.

FIELD OF THE INVENTION 
This invention relates to silver halide photographic elements. The 
photographic element has silver chloride emulsions which contain small 
amounts of iodide and are sensitized with cyanine dyes. 
BACKGROUND OF THE INVENTION 
Silver halide photography usually involves the exposure of silver halide 
photographic element with light in order to form a latent image that is 
developed during photographic processing to form a visible image. Silver 
halide is intrinsically sensitive only to light in the blue region of the 
spectrum. In order to sensitize the silver halide to light other than the 
blue region, sensitizing dyes are used in the silver halide emulsion. 
Sensitizing dyes are chromophoric compounds (usually cyanine dye 
compounds). Their usual function is to be adsorbed to the silver halide 
and then to absorb light (usually other than blue light) and transfer that 
energy to the silver halide grain thus, rendering the silver halide 
sensitive to radiation of a wavelength other than the blue intrinsic 
sensitivity. However, sensitizing dyes can also be used to augment the 
sensitivity of silver halide in the blue region of the spectrum. 
Generally a sensitizing dye should wash out of the photographic element 
during processing. Any retained sensitizing dye contributes to Dmin and is 
often referred to as sensitizing dye stain. Dye stain adversely affects 
the image recorded in the photographic material and has been a source of 
concern for many years. The problem of retained sensitizing dye stain has 
been aggravated by the advent of new emulsions, such as tabular emulsion 
grains, which have more surface area and require higher dye levels and 
accordingly tend to give higher levels of dye stain. Additionally, the use 
of high chloride emulsions makes preferable the use of sensitizing dyes 
having enhanced adsorption to silver halide since sensitizing dyes tend to 
be inherently less well adsorbed to silver chloride emulsions. 
Because sensitizing dyes are less well absorbed to silver chloride, efforts 
to design green sensitizing dyes which show improved aggregation on silver 
chloride have been the subject of much research over the last several 
years since the introduction of high chloride emulsions in the 1980's. 
This effort has led to the development of many new dyes which show 
enhanced sensitivity on silver chloride but frequently at the expense of 
increased dye stain. Thus increasing the dye's tendency to aggregate can 
also lead to higher levels of dye stain. 
High chloride emulsions are also often subjected to rapid processing, which 
can further aggravate dye stain problems since the dyes in the 
photographic element have less time to wash out or be bleached in the 
development or bleach-fix process. 
Modern color photographic printing papers employ silver halide emulsions 
having a high chloride content in order to obtain rapid processing rates 
relative to silver chlorobromide emulsions. 
In order to reduce dye stain, stain-reducing agents, such as bis-triazine 
stilbene compounds, also known as optical brighteners, have been used to 
reduce dye stain. These compounds, however, are expensive and can be 
difficult to incorporate in the hydrophilic layers of photographic 
materials. Another method for reducing dye stain in some cases is to 
incorporate certain substituents into the dye molecule to reduce dye 
stain. For example, dyes containing N,N'-2-hydroxy-3-sulfopropyl nitrogen 
substituents (U.S. Pat. No. 3,424,586) are generally less retained than 
the corresponding dyes with 3-sulfopropyl groups. Other stain-reducing 
nitrogen substituents have also been disclosed such as the 
2-sulfoethylcarbamoylmethyl groups disclosed in U.S. Pat. No 5,091,298. 
Although the foregoing dye structure modifications can be effective at 
reducing dye stain, they have not eliminated the problem. In addition, 
there is an important class of green spectral sensitizers for which it is 
not possible to use these types of stain- reducing nitrogen substituents. 
In this class are benzoxazole dyes, which are commonly used to afford 
green sensitization in many photographic products such as color negative 
and reversal films, and color paper. 
Green sensitizing dyes of the types described in European Application 
Numbers 92303190.9, 93203191.7, 93203192.5, and 93203193.3 have been shown 
to give reduced dye stain, even in the absence of the stain-reducing 
agents in the developer. However, many of these low-stain dyes are not 
efficient sensitizers on high chloride emulsions even those which also 
contain small amounts of bromide (i.e., less than 2 mole percent). 
Shiba et al in U.S. Pat. No. 3,865,598 describes the effect of improved 
green dye adsorption of J-band sensitizers obtained by adding small 
amounts of iodide to silver chlorobromide emulsions. Shiba states (col. 2, 
line 10) that "silver chloride emulsions are not suitable as silver halide 
emulsions for the green layer" . . . having "the fault that development 
proceeds too rapidly and the emulsion is easily fogged as compared to the 
silver chlorobromide emulsion." 
Shiba's invention is based upon the addition of aqueous potassium iodide to 
a preformed silver chlorobromide emulsion. He states (col. 3, line 56) 
that the preferred amount of iodide added is 0.5 to 10 mole percent. Less 
than 0.5 mole percent iodide results in a small effect and more than 10 
mole percent results in low contrast (col. 4, line 6). 
Problem to be Solved by the Invention 
There remains a need for improved sensitization. There is a particular need 
for improved sensitization of chloroiodide emulsions with green 
sensitizing dyes to form emulsions of high photographic sensitivity and 
low stain. 
SUMMARY OF THE INVENTION 
It is an object of the invention to overcome disadvantages of a prior green 
sensitization of chloroiodide emulsions. 
The object of the invention is to provide a green light sensitive silver 
halide emulsion that can be rapidly processed in color developers and 
which has high photographic sensitivity and low stain. 
It is another object of the invention to provide improved sensitization of 
chloroiodide emulsions. 
It is a further object to provide high sensitivity with classes of dyes not 
previously suitable for green sensitization. 
These and other objects of the invention generally are accomplished by 
providing a photographic element comprising a silver halide emulsion 
wherein at least one layer contains a silver chloroiodide emulsion 
containing at least 95 mole percent chloride and contains a sensitizing 
dye of the following general formula (I): 
##STR2## 
wherein: Z1 represents a halogen, a cyano group, an amide substituted 
aromatic group, or a heteroaromatic group that is directly appended to the 
benzene ring shown or an aromatic group that is attached through an amide 
linking group and 
Z2 represents a substituted or unsubstituted alkyl group, substituted or 
unsubstituted alkoxy group, cyano group, a substituted or unsubstituted 
amide group, a substituted or unsubstituted carbamoyl group, halogen, an 
amide substituted aromatic group, or a heteroaromatic group that is 
directly appended to the benzene ring shown or an aromatic group that is 
attached through an amide linking group and 
W1 is one or more ions as needed to balance the charge on the molecule and 
R1 and R2 are, independently, substituted or unsubstituted alkyl group and 
R3 is H or a substituted or unsubstituted lower alkyl group or a 
substituted or unsubstituted aryl. 
In a preferred form of the invention, the emulsion comprises a radiation 
sensitive emulsion comprised of a dispersing medium and silver 
chloroiodide grains wherein the silver chloroiodide grains are comprised 
of three pairs of equidistantly spaced parallel {100} crystal faces and 
contain from 0.05 to 1 mole percent iodide, based on total silver, with 
maximum iodide concentrations located nearer the surface of the grains 
than their center. 
Advantageous Effect of the Invention 
The invention has the advantage that the green light sensitive silver 
chloroiodide emulsion exhibits high photographic sensitivity and low 
stain. The dyes of the invention are low staining, as well as of 
reasonable cost. Further, the photographic element of the invention is not 
required to contain dye stain removers in the photographic element or in 
the developing bath. In the alternative the stain remover may be 
significantly reduced from what is in conventional processing solutions. 
Such dye stain removers increase cost, as well as being difficult to 
incorporate and sometimes having undesirable photographic effects on the 
element. These and other advantages will be apparent from the description 
below. 
DETAILED DESCRIPTION OF THE INVENTION 
We have described in U.S. Ser. No. 08/362,283 of Chen et al filed Dec. 22, 
1994 a method for the introduction of iodide into the silver chloride 
emulsion which gives improved sensitivity and does not increase fog or 
lower contrast which overcomes Shiba's shortcomings. 
We have found that many low staining dyes, some of which are described in 
European Application Numbers 92303190.9, 93203191.7, 93203192.5, and 
93203193.3 can afford excellent sensitizing efficiency when they are used 
to sensitize an emulsion having a high chloride and low iodide content. 
This dye and emulsion combination can be used to afford a silver halide 
photographic elements with excellent sensitivity and that can be processed 
rapidly and with reduced levels of stain reducing compounds such as 
Phorwite REU in the color developer solution. 
In the present application, the term "aromatic" refers to aromatic rings as 
described in J. March, Advanced Organic Chemistry, Chapter 2 (1985, 
publisher John Wiley & Sons, New York, N.Y.). Examples of aromatic groups 
are phenyl, 3-hydroxyphenyl, 4-carbamoylphenyl, etc. Heteroaromatic refers 
to an aromatic group that contains a heteroatom (e.g., pyrrole-1-yl group, 
furan-2-yl group, etc.). 
Reference in this application to any chemical "group" (such as alkyl group, 
aryl group, heteroaryl group, and the like) includes the possibility of it 
being both substituted or unsubstituted (for example, alkyl group and aryl 
group include substituted and unsubstituted alkyl and substituted and 
unsubstituted specifically stated, substituent groups usable on molecules 
herein include any groups, whether substituted or unsubstituted, which do 
not destroy properties necessary for the photographic utility. It will 
also be understood throughout this application that reference to a 
compound of a particular general formula includes those compounds of other 
more specific formula which specific formula falls within the general 
formula definition. 
As already mentioned, Z1 and Z2 may represent an aromatic group that is 
attached through an amide linking group, where the substituent can be 
attached to either end of the linking group, e.g., Z1-NH--CO'-- or 
Z1-CO--NH--. The linking group can be substituted with aromatic or 
nonaromatic groups, e.g. methyl. 
Examples of Z1 and Z2 include a pyrrole-1-yl group, furan-2-yl group, 
thiophene-2-yl group, benzencarboxamido group, 4-carbamoylphenyl group and 
pyrrolecarboxamido group such as shown below: 
##STR3## 
where R', is hydrogen, an alkyl group (for example, methyl, ethyl or 
2-hydroxyethyl), or an aryl group (for example, phenyl or 
4-hydroxyphenyl), and Y can be N-R', O, S. 
R3 is H or a substituted or unsubstituted lower alkyl group (e.g., methyl, 
ethyl) or a substituted or unsubstituted aryl (e.g., phenyl). 
Preferably, R1 and R2 are both alkyl groups; for example, both may be 1-8 
(or 1 to 4) carbon alkyl groups, and may be the same or different. At 
least one of R1 or R2 is preferably substituted by an acid or acid salt 
group, and preferably both R1 and R2 may be substituted by an acid or acid 
salt group. Acid salt groups include carboxy, sulfo, phosphato, phosphono, 
sulfonamido, sulfamoyl, or acylsulfonamido (groups such as 
--CH2--CO--NH--SO2--CH3) groups. Note that reference to acid or acid salt 
groups are used to define only the free acid groups or their corresponding 
salts, and do not include esters where there is no ionizable or ionized 
proton. Particularly preferred are the carboxy and sulfo groups (for 
example, 3-sulfobutyl, 4-sulfobutyl, 3-sulfopropyl, 2-sulfoethyl, 
carboxymethyl, carboxyethyl, carboxypropyl and the like). 
W1 is one or more ions as needed to balance the charge on the molecule, 
since R1 and R2 are preferably both substituted by an acid or acid salt 
group, W1 will typically be a cation. Examples of suitable cations include 
sodium, potassium, and triethylammonium. While it is preferred that Z1 and 
Z2 be the only substituents on their benzene rings, it is also possible 
that rings may be further substituted with other substituents that do not 
affect the sensitizing efficiency of the invention compounds. Typical of 
such substituents would be alkyl or methoxy groups. 
Substituents on any of the specified groups defined above that can be 
substituted (including any of those substituents described for Z1 or Z2) 
can include substituents such as halogen (for example, chloro, fluoro, 
bromo), alkoxy (particularly 1 to 10 carbon atoms; for example, methoxy, 
ethoxy), substituted or unsubstituted alkyl (particularly of 1 to 10 
carbon atoms, for example, methyl, trifluoromethyl), amido or carbamoyl 
(particularly of 1 to 10 or 1 to 6 carbon atoms), alkoxycarbonyl 
(particularly of 1 to 10 or 1 to 6 carbon atoms), and other known 
substituents, and substituted and unsubstituted aryl ((particularly of 1 
to 10 or 1 to 6 carbon atoms) for example, phenyl, 5-chlorophenyl), 
thioalkyl (for example, methylthio or ethylthio), hydroxy or alkenyl 
(particularly of 1 to 10 or 1 to 6 carbon atoms) and others known in the 
art. Additionally, any of the substituents may optionally be non-aromatic.

Examples of Formula I compounds used in photographic elements of the 
present invention are listed below in Table I: 
TABLE 1 
______________________________________ 
##STR4## 
Dye Z1 Z2 R1,R2 
______________________________________ 
I-1 Benzenecarboxamido F SP,SP 
I-2 Benzenecarboxamido Cl SP,SP 
I-3 Pyrrole-1-yl F SP,SP 
I-4 Phenylcarbamoyl Cl SP,SP 
I-5 p-Acetamidophenyl Cl SE,SP 
I-6 3-Hydroxybenzenecarboxamido 
Cl SP,SP 
I-7 o-Acetamidophenyl F 3SB,SP 
I-8 p-Acetamidophenyl F SP,SP 
I-9 Pyrrolecarboxamido Cl SP,SP 
I-10 Pyrrolecarboxamido F 3SB,SP 
I-11 Furancarboxamido Cl 4SB,4SP 
I-12 Furancarboxamido F 4SB,SP 
I-13 Cl Cl SP,SP 
I-14 2-Hydroxybenzenecarboxamido 
F 3SB,SP 
I-15 Thiophenecarboxamido 
Cl 3SB,SP 
I-16 F F SP,SP 
I-17 Furancarboxamido Z1 SE,SE 
I-18 2-Hydroxybenzenecarboxamido 
Cl 3SB,SP 
______________________________________ 
SP is 3sulfopropyl, 3SB is 3sulfobutyl, 4SB is 4sulfobutyl 
Dyes of Formula I can be prepared according to techniques that are well 
known in the art, such as described in Hamer, Cyanine Dyes and Related 
Compounds, 1964 (publisher John Wiley & Sons, New York, N.Y.) and T. H. 
James, editor, The Theory Of the Photographic Process, 4th Edition, 
Macmillan, New York, 1977. The synthesis of dyes with furan and pyrrole 
nuclei is described in European Application Number 93203192.5. The 
synthesis of amide substituted dyes is described in European Application 
Number 92303190.9. 
The amount of sensitizing dye that is useful to sensitize a silver halide 
emulsion in the photographic elements of the present invention will 
typically be from 0.001 to 4 millimoles per mole of silver halide, but is 
preferably in the range of 0.01 to 1.0 millimoles per mole of silver 
halide. Optimum dye concentrations can be determined by methods known in 
the art. 
The invention finds its preferred embodiment in the sensitization of silver 
chloroiodide grains such as formed in U.S. Ser. No. 08/362,283 of Chen et 
al filed Dec. 22, 1994 which is coowned and coassigned and incorporated by 
reference herein. The preferred embodiment utilizes grains that are a 
radiation sensitive emulsion comprised of a dispersing medium and silver 
chloroiodide grains wherein the silver chloroiodide grains are comprised 
of three pairs of equidistantly spaced parallel {100} crystal faces and 
contain from 0.05 to 1 mole percent iodide, based on total silver, with 
maximum iodide concentrations located nearer the surface of the grains 
than their center. It is most preferred that the grains have at least one 
{111} crystal face. 
It is preferred that the grain size coefficient of variation of the silver 
chloroiodide grains is less than 35 percent or most preferably less than 
25 percent. 
It is also preferred that the invention radiation sensitive emulsion 
chloroiodide grains contain from 0.1 to 0.6 mole percent iodide, based on 
total silver, that maximum iodide concentrations in the silver 
chloroiodide grains are confined to exterior portions accounting for up to 
15 percent of the total silver forming the grains, and that the maximum 
iodide concentrations are located in grain portions forming one or more 
surfaces of the grains. The iodide forming the grains is generally 
confined to exterior portions of the grains accounting for up to 50 
percent of total silver and is preferably confined to exterior portions of 
the grains accounting for up to 15 percent of total silver forming the 
grains. 
The radiation sensitive emulsion, of the invention, preferably has 
chloroiodide grains that include tetradecahedral grains having {111} and 
{100} crystal faces and contain a reciprocity improving dopant such as 
iridium dopant. 
The radiation sensitive emulsions used in the invention preferably contain 
as an antifoggant a compound containing a mercapto group bonded to a 
carbon atom which is linked to an adjacent nitrogen atom in a heterocyclic 
ring system, such as a 5-mercaptotetrazole including a phenyl substituted 
5-mercaptotetrazole, with the phenyl group either being unsubstituted or 
containing a substituent chosen from among alkoxy, phenoxy, halogen, 
cyano, nitro, amino, amido, carbamoyl, sulfamoyl, sulfonamido, sulfo, 
sulfonyl, carboxy, carboxylate, ureido, and carbonyl groups. 
The radiation sensitive emulsion also may contain as an antifoggant a 
quaternary aromatic chalcogenazolium salt wherein the chalcogen is sulfur, 
selenium, or tellurium such as a benzothiazolium salt or a 
benzoselenazolium salt. 
The emulsion suitable may have as an antifoggant a triazole or tetrazole 
containing an ionizable hydrogen bonded to a nitrogen atom in a 
heterocyclic ring system. 
Other suitable antifoggants include as an antifoggant a benzotriazole or a 
tetraazaindene and a dichalcogenide compound comprising an --X--X-- 
linkage between carbon atoms wherein each X is divalent sulfur, selenium, 
or tellurium. 
Photographic elements of the present invention can be black and white 
elements, single color elements or multicolor elements. Multicolor 
elements contain dye image-forming units sensitive to each of the three 
primary regions of the spectrum. Each unit can be comprised of a single 
emulsion layer or of 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. 
The invention materials find use in any color paper wherein an improved 
green sensitive emulsion is desired. The other materials in the color 
paper may be any of those conventionally utilized. Materials suitable for 
use in color papers may be found in Research Disclosure 37038 of February, 
1995. Suitable couplers for use in the invention may be found in Section 
II of Research Disclosure 37038. Emulsions for use in the red and blue 
layers may be found in those described in Section XV of Research 
Disclosure 37038. Further, the emulsions such as utilized in the invention 
green layer also may be utilized in the other layers of a color paper in 
accordance with this invention. Suitable fog inhibitors may be found at 
Section IV of Research Disclosure 37038. A typical format for color paper 
may be found at Sections VII and VIII of Research Disclosure 37038. Such 
formats are suitable for forming the three-layered color paper that is in 
accordance with the invention with the utilization of the green layer of 
the invention. 
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. All of these 
can be coated on a support which can be transparent or reflective (for 
example, a paper support). Photographic elements of the present invention 
may also usefully include a magnetic recording material as described in 
Research Disclosure, Item 34390, November 1992, or a transparent magnetic 
recording layer such as a layer containing magnetic particles on the 
underside of a transparent support as in U.S. Pat. Nos. 4,279,945 and 
4,302,523. The element typically will have a total thickness (excluding 
the support) of from 5 to 30 microns. While the order of the color 
sensitive layers can be varied, they will normally be red-sensitive, 
green-sensitive and blue-sensitive, in that order on a transparent 
support, (that is, blue sensitive furthest from the support) and the 
reverse order on a reflective support being typical. 
The present invention also contemplates the use of photographic elements of 
the present invention in what is often referred to as single use cameras 
(or "film with lens" units). These cameras are sold with film preloaded in 
them and the entire camera is returned to a processor with the exposed 
film remaining inside the camera. Such cameras may have glass or plastic 
lenses through which the photographic element is exposed. 
In the following discussion of suitable materials for use in elements of 
this invention, reference will be made to Research Disclosure, September 
1994, Number 365, Item 36544, identified hereafter by the term "Research 
Disclosure I." The Sections hereafter referred to are Sections of the 
Research Disclosure I unless otherwise indicated. All Research Disclosures 
referenced herein are published by Kenneth Mason Publications, Ltd., 
Dudley Annex, 12a North Street, Emsworth, Hampshire P010 7DQ, ENGLAND. 
The photographic elements of the present invention may also use colored 
couplers (e.g., to adjust levels of interlayer correction) and masking 
couplers such as those described in EP 213 490; Japanese Published 
Application 58-172,647; U.S. Pat. No. 2,983,608; German Application DE 
2,706,117C; U.K. Patent 1,530,272; Japanese Application A-113935; U.S. 
Pat. No. 4,070,191 and German Application DE 2,643,965. The masking 
couplers may be shifted or blocked. 
The photographic elements may also contain materials that accelerate or 
otherwise modify the processing steps of bleaching or fixing to improve 
the quality of the image. Bleach acceleraors described in EP 193 389; EP 
301 477; U.S. Pat. Nos. 4,163,669; 4,865,956; and 4,923,784 are 
particularly useful. Also contemplated is the use of nucleating agents, 
development accelerators or their precursors (U.K. 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. 
The elements may also contain filter dye layers comprising colloidal silver 
sol or yellow and/or magenta filter dyes and/or antihalation dyes 
(particularly in an undercoat beneath all light sensitive layers or in the 
side of the support opposite that on which all light sensitive layers are 
located) either as oil-in-water dispersions, latex dispersions or as solid 
particle dispersions. Additionally, they may be used with "smearing" 
couplers (e.g., as described in U.S. Pat. No. 4,366,237; EP 096 570; U.S. 
Pat. Nos. 4,420,556; and 4,543,323.) Also, the couplers may be blocked or 
coated in protected form as described, for example in Japanese Application 
61/258,249 or U.S. Pat. No. 5,019,492. 
The photographic elements may further contain other image-modifying 
compounds such as "Developer Inhibitor-Releasing" compounds (DIR's). 
Useful additional DIR's for elements of the present invention, are known 
in the art and examples are described in U.S. Pat. Nos. 3,137,578; 
3,148,022; 3,148,062; 3,227,554; 3,384,657; 3,379,529; 3,615,506; 
3,617,291; 3,620,746; 3,701,783; 3,733,201; 4,049,455; 4,095,984; 
4,126,459; 4,149,886; 4,150,228; 4,211,562; 4,248,962; 4,259,437; 
4,362,878; 4,409,323; 4,477,563; 4,782,012; 4,962,018; 4,500,634; 
4,579,816; 4,607,004; 4,618,571; 4,678,739; 4,746,600; 4,746,601; 
4,791,049; 4,857,447; 4,865,959; 4,880,342; 4,886,736; 4,937,179; 
4,946,767; 4,948,716; 4,952,485; 4,956,269; 4,959,299; 4,966,835; 
4,985,336, as well as in patent publications GB 1,560,240; GB 2,007,662; 
GB 2,032,914; GB 2,099,167; DE 2,842,063, DE 2,937,127; DE 3,636,824; DE 
3,644,416, as well as the following European Patent Publications: 272,573; 
335,319; 336,411; 346, 899; 362, 870; 365,252; 365,346; 373,382; 376,212; 
377,463; 378,236; 384,670; 396,486; 401,612; 401,613. 
DIR compounds are also disclosed in "Developer-Inhibitor-Releasing (DIR) 
Couplers for Color Photography," C. R. Barr, J. R. Thirtle and P. W. 
Vittum in Photographic Science and Engineering, Vol. 13, p. 174 (1969), 
incorporated herein by reference. 
It is also 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. The emulsions and 
materials to form elements of the present invention, may be coated on pH 
adjusted support as described in U.S. Pat. No. 4,917,994; with epoxy 
solvents (EP 0 164 961); with additional stabilizers (as described, for 
example, in U.S. Pat Nos. 4,346,165; 4,540,653 and 4,906,559); 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. Nos. 5,068,171 and 
5,096,805. Other compounds useful in the elements of the invention are 
disclosed in Japanese Published Applications 83-09,959; 83-62,586; 
90-072,629, 90-072,630; 90-072,632; 90-072,633; 90-072,534; 90-077,822; 
90-078,229; 90-078,230; 90-079,336; 90-079,338; 90-079,690; 90-079,691; 
90-080,487; 90-080,489; 90-080,490; 90-080,491; 90-080,492; 90-080,494; 
90-085,928; 90-086,669; 90-086,670; 90-087,361; 90-087,362; 90-087,363; 
90-087,364; 90-088,096; 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; 90-101,937; 
90-103,409; 90-151,577. 
The silver halide to be used in the invention may be advantageously 
subjected to chemical sensitization with noble metal (for example, gold) 
sensitizers, middle chalcogen (for example, sulfur) sensitizers, reduction 
sensitizers and others known in the art. Compounds and techniques useful 
for chemical sensitization of silver halide are known in the art and 
described in Research Disclosure I and the references cited therein. 
The photographic elements of the present invention, as is typical, provide 
the silver halide in the form of an emulsion. Photographic emulsions 
generally include a vehicle for coating the emulsion as a layer of a 
photographic element. Useful vehicles include both naturally occurring 
substances such as proteins, protein derivatives, cellulose derivatives 
(e.g., cellulose esters), gelatin (e.g., alkali-treated gelatin such as 
cattle bone or hide gelatin, or acid treated gelatin such as pigskin 
gelatin), gelatin derivatives (e.g., acetylated gelatin, phthalated 
gelatin, and the like), and others as described in Research Disclosure I. 
Also useful as vehicles or vehicle extenders are hydrophilic 
water-permeable colloids. These include synthetic polymeric peptizers, 
carriers, and/or binders such as poly(vinyl alcohol), poly(vinyl lactams), 
acrylamide polymers, polyvinyl acetals, polymers of alkyl and sulfoalkyl 
acrylates and methacrylates, hydrolyzed polyvinyl acetates,. polyamides, 
polyvinyl pyridine, methacrylamide copolymers, and the like, as described 
in Research Disclosure I. The vehicle can be present in the emulsion in 
any amount useful in photographic emulsions. The emulsion can also include 
any of the addenda known to be useful in photographic emulsions. These 
include chemical sensitizers, such as active gelatin, sulfur, selenium, 
tellurium, gold, platinum, palladium, iridium, osmium, rhenium, 
phosphorous, or combinations thereof. Chemical sensitization is generally 
carried out at pAg levels of from 4 to 10, pH levels of from 4 to 8, and 
temperatures of from 30.degree. to 80.degree. C., as described in Research 
Disclosure I, Section IV (pages 510-511) and the references cited therein. 
The silver halide may be sensitized by sensitizing dyes of formula (I) for 
a green sensitive emulsion, or other sensitizing dyes, by any method known 
in the art, such as described in Research Disclosure I. Any of the dyes 
may be added to the emulsion of the silver halide grains which it is to 
sensitize, and a hydrophilic colloid at any time prior to (e.g., during or 
after chemical sensitization) or simultaneous with the coating of the 
emulsion on a photographic element. The dyes may, for example, be added as 
a solution in water or an alcohol. The dye/silver halide emulsion may be 
mixed with a dispersion of color image-forming coupler immediately before 
coating or in advance of coating (for example, 2 hours). 
Photographic elements of the present invention are preferably imagewise 
exposed using any of the known techniques, including those described in 
Research Disclosure I, Section XVI. This typically involves exposure to 
light in the visible region of the spectrum, and typically such exposure 
is of a live image through a lens, although exposure can also be exposure 
to a stored image (such as a computer stored image) by means of light 
emitting devices (such as light emitting diodes, CRT and the like). 
Photographic elements comprising the composition of the invention can be 
processed in any of a number of well-known photographic processes 
utilizing any of a number of well-known processing compositions, 
described, for example, in Research Disclosure I, or in T. H. James, 
editor, The Theory of Photographic Process, 4th Edition, Macmillan, New 
York, 1977. In the case of processing a negative working element, the 
element is treated with a color developer (that is, one which will form 
the colored image dyes with the color couplers), and then with an oxidizer 
and a solvent to remove silver and silver halide. In the case of 
processing a reversal color element, the element is first treated with a 
black and white developer (that is, a developer which does not form 
colored dyes with the coupler compounds) followed by a treatment to fog 
silver halide (usually chemical fogging or light fogging), followed by 
treatment with a color developer. Preferred color developing agents are 
p-phenylenediamines. Especially preferred are: 
4-amino N,N-diethylaniline hydrochloride, 
4-amino-3-methyl-N,N-diethylaniline hydrochloride, 
4-amino-3-methyl-N-ethyl-N-(.beta.-(methanesulfonamido) ethylaniline 
sesquisulfate hydrate, 
4-amino-3-methyl-N-ethyl-N-(.beta.-hydroxyethyl)aniline sulfate, 
4-amino-3-.beta.-(methanesulfonamido)ethyl-N,N- diethylaniline 
hydrochloride and 4-amino-N-ethyl-N-(2-methoxyethyl)-m-toluidine 
di-p-toluene sulfonic acid. 
Development is followed by bleach-fixing, to remove silver or silver 
halide, washing and drying. 
The present invention will be further described in the examples below. The 
structures of comparison dyes C-1 and C-2 are in Table IB. 
TABLE IB 
______________________________________ 
##STR5## 
Dye Z1 Z2 R1,R2 
______________________________________ 
C-1 Phenyl Cl 3SB,SP 
Comparison 
C-2 Acetamido Z1 SP,SP 
Comparison 
______________________________________ 
Photographic Examples 
Emulsion 1: 
A reaction vessel containing 5.7 liters of a 3.9 percent by weight gelatin 
aqueous solution and 1.44 grams of 1,8-dihydroxy-3,6-dithiaoctane was 
adjusted to a temperature of 46.degree. C., pH of 5.8, and a pAg of 7.2 by 
the addition of sodium chloride solution. A 2.00 molar aqueous solution of 
silver nitrate and a 2.00 molar aqueous solution of sodium chloride were 
simultaneously run into the reaction vessel with vigorous stirring. The 
flow rates held constant at 0.50 moles/minute and the silver potential was 
controlled at 7.2 pAg. The emulsion was washed to remove excess salts. A 
total of 10 moles of silver chloride emulsion was precipitated. The 
emulsion having cubic morphology and 0.39 micron average cubic edge 
length. 
Emulsion 2: 
Emulsion 2 was prepared in a manner exactly like emulsion 1, except that at 
point in time equivalent to where 93% of the silver had been added, an 
aqueous solution containing 0.030 moles of potassium iodide was rapidly 
added to the reactor. 
Chemical and Spectral Sensitization: 
Emulsion 1 was sensitized using the following procedure: 
An aliquot of emulsion 1 was melted at 40.degree. C. and a methanolic 
solution containing the equivalent of 2.84.times.10.sup.-4 M/Ag-M of green 
spectral sensitizing dye (Table I or IB) was added followed by an aqueous 
suspension of gold sulfide in the amount of 4.69.times.10.sup.-5 M/Ag-M. 
The temperature of the mixture was rapidly raised to 70.degree. C. and 
held for 30 minutes to effect chemical ripening. After cooling to 
40.degree. C., an aqueous solution of 
1-(3-acetamidophenyl)-5-mercaptotetrazole was added in the amount of 
5.1.times.10.sup.-5 M/Ag-M. This was followed by the addition of an 
aqueous solution of potassium bromide in the amount of 1.0 mole percent, 
which completed the sensitization. 
Emulsion 2 was sensitized using the procedure described for emulsion 1 
except that the addition of potassium bromide was omitted. 
The sensitization process was repeated for each, emulsion and for each of 
the different sensitizing dyes described in Table 1 and 1B. 
Single Layer Coating Evaluation Format: 
The emulsions described above were first evaluated in a single emulsion 
layer coating format using conventional coating preparation methods and 
techniques. This coating format is described below in detail: 
TABLE 2 
______________________________________ 
Single Layer Coating Format 
Coating 
Layer Material Coverage mg/m.sup.2 
______________________________________ 
Overcoat Gelatin 1064. 
Gel hardener 
105. 
Emulsion/Coupler 
Emulsion 1 or 2 
279.0 
Coupler M1 430.0 
Solvent S1 107.6 
Stabilizer ST1 
183.0 
Antioxidant AO1 
43.0. 
Gelatin 1596. 
Sub-layer Gelatin 3192 
Resin coated paper 
support 
______________________________________ 
M-1 
##STR6## 
ST2 
##STR7## 
S1 is dibutyl phthlate 
AO1 is dioctylhydroquinine 
Gel hardener is bis-vinylsulfonylmethyl ether 
Once the coated paper samples described above had been prepared, they were 
evaluated as follows: 
The respective single layer color paper samples were exposed to light in a 
Kodak Model 1B sensitometer with a color temperature of 3000.degree. K. 
which was filtered with a Kodak Wratten.sup.TM.TM. 2C filter. Exposure 
time was adjusted to 0.1 seconds. The exposures were performed by 
contacting the paper samples with a neutral stepped exposure tablet having 
an exposure range of 0 to 3 log-E. 
The samples described above were processed in the Kodak Ektacolor RA-4 
Color Development.TM. process. The color developer and bleach-fix 
formulations are described below in Tables 3 and 4. The chemical 
development process cycle is described in Table 5. 
TABLE 3 
______________________________________ 
The Kodak Ektacolor RA-4 Color Developer: 
Chemical Grams/Liter 
______________________________________ 
Triethanol amine 12.41 
Phorwite REU .TM. (Mobay Chemical) 
2.30 
Lithium polystyrene sulfonate (30%) 
0.30 
N,N-diethylhydroxylamine (85%) 
5.40 
Lithium sulfate 2.70 
Kodak color developer CD-3 
5.00 
DEQUEST 2010 .TM. (60%) 
1.16 
Potassium carbonate 21.16 
Potassium bicarbonate 
2.79 
Potassium chloride 1.60 
Potassium bromide 0.007 
Water to make 1 liter 
pH @ 26.7.degree. C. is 10.04 +/- 0.05 
______________________________________ 
TABLE 4 
______________________________________ 
The Kodak Ektacolor RA-4 Bleach-Fix consists of: 
Chemical Grams/Liter 
______________________________________ 
Ammonium thiosulfate (56.5%) 
127.40 
Sodium metabisulfite 
10.00 
Glacial acetic acid 
10.20 
Ammonium ferric EDTA (44%) 
110.40 
Water to make 1 liter 
pH @ 26.7.degree. C. is 5.5 +/- 0.10 
______________________________________ 
TABLE 5 
______________________________________ 
Kodak Ektacolor RA-4 Color Paper Process 
Process Step Time (seconds) 
______________________________________ 
Color Development 
45 
Bleach-fix 45 
Wash 90 
Dry 
______________________________________ 
Processing the exposed paper samples is performed with the developer and 
bleach-fix temperatures adjusted to 35.degree. C. Washing is performed 
with tap water at 32.2.degree. C. 
TABLE 6 
______________________________________ 
Comparison the Spectral Sensitivities 
of a Bromochloride vs. and Chloroiodide Emulsion 
Sensitized with Various Green Spectral Dyes 
Sensitivity 
Sensitivity 
Sensitivity 
log E log E Change Dye 
Sensitizing 
Br.sub.-- Cl 
I.sub.-- Cl 
log E Stain 
Dye Comparison Invention (I.sub.-- Cl--Br.sub.-- Cl) 
b* 
______________________________________ 
C-1 1.80 2.14 0.34 -5.0 
Comparison 
C-2 0.00 0.00 0.00 -6.3 
Comparison 
I-16 0.00 1.81 1.81 -6.5 
I-13 0.18 1.85 1.67 -6.5 
I-2 1.72 2.03 0.31 -5.8 
I-1 1.49 2.04 0.55 -6.3 
I-4 1.31 1.93 0.62 -6.0 
I-5 1.18 2.04 0.86 -5.3 
I-8 0.81 1.94 1.13 -5.8 
I-7 0.76 1.99 1.23 -5.8 
I-18 0.00 2.16 2.16 -5.2 
I-14 0.46 2.14 1.68 -5.6 
I-6 1.16 2.22 1.06 -5.6 
I-15 0.40 2.04 1.64 -5.5 
I-11 0.63 2.13 1.50 -6.1 
I-12 0.35 1.94 1.59 -6.3 
I-17 0.09 2.18 2.09 -6.2 
I-9 0.99 2.14 1.15 -6.0 
I-10 0.67 2.02 1.35 -6.3 
I-3 1.48 2.11 0.63 -6.2 
______________________________________ 
The data shown in Table 6 above compare the spectral responses of the two 
emulsions as a function of the different Green spectral sensitizing dyes. 
There are several points to be observed in this table. First is that not 
all the spectral sensitizing dyes sensitize the bromochloride emulsion, as 
the range of sensitivities extends from 0 (no sensitization) to 1.8 log E; 
whereas all of the dyes are shown to efficiently sensitize the 
chloroiodide emulsion with the lowest of the sensitivities of the 
chloroiodide emulsion exceeding the best sensitivities of the 
bromochloride emulsion. The increase in sensitivities can be summarized by 
comparing the sensitivity difference between the two emulsions and is 
given in the third column. This sensitivity difference shows a remarkable 
range of sensitivity increases of the chloroiodide emulsion compared to 
the bromochloride emulsion of approximately 1.8 log E. 
Also shown in Table 6 is the dye stain of the element after being processed 
in the Kodak Ektacolor RA-4 Color Developer but without the stain reducing 
agent, Phorwite REU. Dye stain can be characterized by measuring the 
colorimetric yellowness of the element as green sensitizing dyes when not 
aggregated on an emulsion are generally yellow in color. The colorimetric 
term b* is a direct measure of how much sensitizing dye remains in the 
element after processing, as it is a measure of yellowness. The metric b* 
is commonly used in the photographic industry, and its definition can be 
obtained from a variety of sources such as The Principles of Color 
Technology, 2nd Edition, by F. W. Billmeyer, Jr. and M. Salzman, John 
Wiley and Sons, New York. 
A positive value of b* means that the object (element) appears to the eye 
as `yellow`, the opposite of blue. A b* value of zero means that the 
object is neither blue nor yellow, and a negative value for b* indicates 
the object is less blue, or more yellow. Thus, the more negative the value 
of b*, the less yellow or bluer the object. In terms of the eyes 
perception of white, bluer (more negative b*) is preferred. 
Since color photographic prints are coated on a reflective support, the 
absolute color of the white Dmin is limited by the `blueness` of the 
support. Also, since sensitizing dyes are generally added in small amounts 
compared to other chemicals in the photographic element, the amount of 
change produced by removing the sensitizing dye stain is small, but yet 
very measureable and very visible to the eye if not removed during 
processing. 
Thus in Table 6, dye C-1 represents the state of the art green sensitizing 
dye, as it provides the current state of the art bromochloride emulsion 
with the highest sensitivity. When used to sensitize the chloroiodide 
emulsion, only a sensitivity increase due to the change in intrinsic 
sensitivity of the emulsion grain caused by the introduction of iodide 
into the grain is observed. When processed in a color developer without 
Phorwite REU, a comparatively `high` b* stain value is obtained and the 
element appears `yellow` when contrasted to a `white`. 
Dye C-2 represents a green spectral sensitizing dye having both the Z1 and 
Z2 substituents as acetamido groups. This dye, presumably because of its 
increased aqueous solubility, does not sensitize either the bromochloride 
or chloroiodide emulsion grain. Because of its increased solubility, the 
dye stain appears `bluer`; i.e.: the b* term is more negative. 
The inventive dyes remaining in the table, all produce sensitivities on the 
chloroiodide emulsion which equal or exceed the comparison dyes on the 
bromochloride emulsion. In addition, these dyes all produce b* values 
which are more negative than C-1 meaning that their dye stain in Phorwite 
REU free processes is reduced when compared to C-1. 
The preceding examples are set forth to illustrate specific embodiments of 
this invention and are not intended to limit the scope of the compositions 
or materials of the invention. It will be understood that variations and 
modifications can be effected within the spirit and scope of the 
invention.