Stable photographic developers containing an indazole antifoggant and a lignosulfonate

Lignosulfonates are incorporated in photographic developing compositions containing an indazole antifoggant in order to prevent or retard the precipitation of the indazole. Both black-and-white developing compositions, containing such developing agents as dihydroxybenzenes and/or pyrazolidones, and color developing compositions, containing primary aromatic amino color developing agents, are effectively stabilized against precipitation of indazole antifoggants by the lignosulfonates.

FIELD OF THE INVENTION 
This invention relates in general to the photographic art and in particular 
to novel photographic developing compositions. More specifically, this 
invention relates to photographic developing compositions containing a 
developing agent, an indazole antifoggant, and an agent which functions to 
suppress precipitation of the indazole antifoggant. 
BACKGROUND OF THE INVENTION 
It is well known to use an indazole as an antifoggant in a photographic 
developing composition. The indazoles have been used for this purpose in 
both black-and-white developing compositions and color developing 
compositions. Among the many patents disclosing such use are Peterson et 
al, U.S. Pat. No. 2,271,229 issued Jan. 27, 1942, which describes the 
incorporation of indazole antifoggants in both black-and-white and color 
developers; British Pat. No. 1,437,053 published May 26, 1976, which 
describes the use of indazoles as antifoggants in X-ray developers; and 
Sincius et al, U.S. Pat. No. 4,172,728, issued Oct. 30, 1979, which 
describes the use of indazoles as antifoggants in developers for graphic 
arts processes. 
While the indazoles are very effective antifoggants, it is frequently 
necessary to utilize them at relatively high concentrations and, under 
such conditions, a serious problem arises in that they tend to undergo 
precipitation. This is particularly the case where a developing solution 
containing an indazole antifoggant is stored at relatively low 
temperatures. Under such conditions, it is common for the indazole to 
precipitate as a very fine crystalline material. This reduces the 
concentration of dissolved indazole which is available to provide 
antifoggant action and is also deleterious because the precipitate can 
adhere to the photographic film or paper and adversely affect its physical 
characteristics. In addition to temperature, there are other factors that 
affect the tendency for precipitation to occur, and it is believed that 
one such factor that is particularly important is the degree of purity of 
the indazole. Thus, for example, very pure indazole antifoggants are 
generally much less soluble than impure indazole antifoggants, since the 
impurities are capable of allowing preparation of solutions that are 
beyond their normal thermodynamic stabilities, i.e., that are both 
supersaturated and stable. However, the inevitable variation in the amount 
and type of impurities present means that there is an inherent instability 
problem associated with the use of indazole antifoggants. This lack of 
stability of developing compositions containing indazole antifoggants has 
seriously hampered their commercial utilization. 
It is toward the objective of providing a stable photographic developing 
composition, in which an indazole is utilized as an antifoggant and in 
which there is little or no tendency for precipitation of the indazole to 
occur, that the present invention is directed. 
SUMMARY OF THE INVENTION 
It has now been discovered that incorporation of a lignosulfonate in a 
photographic developing composition containing an indazole antifoggant 
will prevent, or at least significantly reduce, precipitation of the 
indazole. The lignosulfonates can be used for this purpose in either 
black-and-white or color developing compositions. Accordingly, this 
invention provides stable photographic developing compositions containing, 
as essential components, a developing agent, an indazole antifoggant, and 
a lignosulfonate in an amount sufficient to suppress precipitation of the 
indazole. 
DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The lignosulfonates are well known commercially available materials. They 
have found extensive industrial application as dispersants, binders, 
chelating agents, flotation reagents, emulsifiers, emulsion stabilizers 
and water treatment agents. While to the best of applicant's knowledge, 
lignosulfonates have not been used heretofore to suppress unwanted 
precipitation of components of photographic developers, they have been 
previously used in photographic processing compositions for other 
purposes. For example, U.S. Pat. No. 2,865,746, "Tinting Bath For 
Photographic Paper," Roy C. Bloom and Henry J. Fassbender, issued Dec. 23, 
1958, describes the use of lignosulfonates in a tinting bath for producing 
old ivory and buff tints on photographic paper. Also, the hemlock tannin 
polymers which, like the lignosulfonates, are chemicals derived from wood, 
have been used in photographic processing compositions, including 
developing compositions, to avoid the formation of unwanted markings 
during continuous transport processing of photograpic materials. This is 
described in U.S. Pat. No. 3,515,556, "Photographic Developing Process 
Utilizing Hemlock Tannin Polymer," Harold D. Russell and Charles E. 
Amering, issued June 2, 1970. As disclosed in this patent, the hemlock 
tannin polymers are very effective in avoiding so-called "pi line 
markings," but the lignosulfonates are not effective for this purpose. 
While applicant does not wish to be bound by any theoretical explanation of 
the manner in which his invention functions, it is believed that the 
lignosulfonates serve in the developing compositions of this invention as 
crystal growth control agents. Such control could involve the formation of 
complexes and/or protective colloid activity which prevents the growth of 
one crystal at the expense of others. 
Lignin is the major noncarbohydrate constituent of wood. The 
lignosulfonates are sulfonate salts which are typically made from the 
lignin of sulfite pulp-mill liquors. They are commercially available as 
ammonium salts and as salts of metals such as sodium or calcium. They are 
hetero-disperse polymers whose molecular weights are typically in the 
range from about 1,000 to about 100,000 and can be characterized as 
water-soluble, anionic, surface-active derivatives of lignin. Their exact 
structural formula is not known. 
Lignosulfonates are available commercially from a number of sources, for 
example, as MARASPERSE dispersants from American Can Company, as LIGNOSOL 
dispersants from the Chemical Division of Reed Ltd., as ORZAN dispersants 
from Crown Zellerbach, as POLYFON dispersants and REAX dispersants from 
Westvaco and as LIGNOSITE dispersants from Georgia Pacific. The commercial 
lignosulfonates differ substantially in their degree of purity, with the 
cruder forms containing a high percentage of wood sugar derivatives. 
Different grades may differ significantly in other factors, such as the 
degree of sulfonation and the molecular weight. 
Lignosulfonates and methods for their preparation have been described in 
the patent literature, for example, in U.S. Pat. Nos. 2,104,701, 2,491,832 
and 4,069,217 and in U.S. Pat. No. Re. 18,268. 
The indazole antifoggants are well known and have been used in photographic 
developing compositions for many years. A wide variety of such compounds 
are effective; all of them being characterized by the presence of the 
indazole nucleus which has the structure: 
##STR1## 
Illustrative examples of the indazole antifoggants include the following: 
5-nitroindazole 
5-aminoindazole 
5-p-toluenesulfonamido indazole 
5-chloroindazole 
5-benzoylacetamino indazole 
5-cyanoindazole 
5-p-nitrobenzoylamino indazole 
1-methyl-5-nitro-indazole 
6-nitroindazole 
3-methyl-5-nitro-indazole 
4-chloro-5-nitro-indazole, and the like. 
The nitroindazoles are preferred for use in the developing compositions of 
this invention. An especially preferred compound is 5-nitroindazole, which 
has the formula: 
##STR2## 
In the practice of this invention, the indazole antifoggants can be used as 
the sole antifoggant in the developing composition. Alternatively, they 
can be used in combination with other antifoggants such as the 
benzotriazoles. 
Developing agents of both organic and inorganic types are well known in the 
photographic art. Useful classes of organic developing agents include 
hydroquinones, catechols, aminophenols, pyrazolidones, phenylenediamines, 
tetrahydroquinolines, bis(pyridone) amines, cycloalkenones, pyrimidines, 
reductones, and coumarins. Useful inorganic developing agents include 
compounds of a metal, having at least two distinct valence states, which 
are capable of reducing ionic silver to metallic silver. Such metals 
include iron, titanium, vanadium, and chromium and the metal compounds 
employed are typically complexes with organic compounds such as 
polycarboxylic acids or aminopolycarboxylic acids. 
A particularly important class of black-and-white developing agents are the 
dihydroxybenzenes such as, for example, 
hydroquinone, 
chlorohydroquinone, 
bromohydroquinone, 
isopropylhydroquinone, 
toluhydroquinone, 
methylhydroquinone, 
2,3-dichlorohydroquinone, 
2,5-dimethylhydroquinone, 
2,3-dibromohydroquinone, 
1,4-dihydroxy-2-acetophenone-2,5-dimethylhydroquinone, 
2,5-diethylhydroquinone, 
2,5-di-p-phenethylhydroquinone, 
2,5-dibenzoylaminohydroquinone, 
2,5-diacetaminohydroquinone, and the like. 
A further particularly important class of black-and-white developing agents 
are the 3-pyrazolidones. Useful compounds of this class include those 
substituted in the 1-position by a monocyclic aryl group of the benzene 
series, including phenyl and substituted phenyl such as p-tolyl, 
p-chlorophenyl, etc. A typical compound of this type is 
1-phenyl-3-pyrazolidone. In addition to this substitution in the 
1-position, the pyrazolidone nucleus can be substituted in the 4-position, 
particularly by lower alkyl and substituted lower alkyl groups such as 
methyl and hydroxymethyl. Representative compounds of this class are: 
1-phenyl-4-methyl-3-pyrazolidone, 
1-phenyl-4-hydroxymethyl-3-pyrazolidone, 
1-phenyl-4,4-dimethyl-3-pyrazolidone, and 
1-phenyl-4,4-di(hydroxymethyl)-3-pyrazolidone. 
Color developers typically contain primary aromatic amino color developing 
agents. These color developing agents are well known and widely used in a 
variety of color photographic processes. They include aminophenols and 
p-phenylenediamines. 
Examples of aminophenol developing agents include o-aminophenol, 
p-aminophenol, 5-amino-2-hydroxy-toluene, 2-amino-3-hydroxy-toluene, 
2-hydroxy-3-amino-1,4-dimethylbenzene, and the like. 
Particularly useful primary aromatic amino color developing agents are the 
p-phenylenediamines and especially the N-N-dialkyl-p-phenylenediamines in 
which the alkyl groups or the aromatic nucleus can be substituted or 
unsubstituted. Examples of useful p-phenylenediamine color developing 
agents include: 
N-N-diethyl-p-phenylenediamine monohydrochloride, 
4-N,N-diethyl-2-methylphenylenediaminemonohydrochloride, 
4-(N-ethyl-N-2-methanesulfonylaminoethyl)-2-methyl-phenylenediamine 
sesquisulfate monohydrate, 
4-(N-ethyl-N-2-hydroxyethyl)-2-methylphenylenediamine sulfate, 
4-N,N-diethyl-2,2'-methanesulfonylaminoethylphenylene-diamine 
hydrochloride, and the like. 
An especially preferred class of p-phenylenediamine developing agents are 
those containing at least one alkylsulfonamidoalkyl substituent attached 
to the aromatic nucleus or to an amino nitrogen. Other especially 
preferred classes of p-phenylenediamines are the 
3-alkyl-N-alkyl-N-alkoxyalkyl-p-phenylenediamines and the 
3-alkoxy-N-alkyl-N-alkoxyalkyl-p-phenylenediamines. These developing 
agents are described in U.S. Pat. Nos. 3,656,950 and 3,658,525 and can be 
represented by the formula: 
##STR3## 
wherein n is an integer having a value of from 2 to 4, R is an alkyl group 
of from 1 to 4 carbon atoms, and R.sup.1 is an alkyl group of from 1 to 4 
carbon atoms or an alkoxy group of from 1 to 4 carbon atoms. Illustrative 
examples of these developing agents include the following compounds: 
N-ethyl-N-methoxybutyl-3-methyl-p-phenylenediamine, 
N-ethyl-N-ethoxyethyl-3-methyl-p-phenylenediamine, 
N-ethyl-N-methoxyethyl-3-n-propyl-p-phenylenediamine, 
N-ethyl-N-methoxyethyl-3-methoxy-p-phenylenediamine, 
N-ethyl-N-butoxyethyl-3-methyl-p-phenylenediamine, and the like. 
In addition to the primary aromatic amino color developing agent, color 
developer compositions typically contain a variety of other agents such as 
alkalies to control pH, bromides, iodides, benzyl alcohol, anti-oxidants, 
solubilizing agents, sequestering agents, brightening agents, and so 
forth. 
The three essential components of the developing compositions of this 
invention, namely the developing agent, the indazole antifoggant and the 
lignosulfonate, can be used in any amount which is effective for the 
intended purpose. The developing agent will generally be used in amounts 
of from about 5 to about 50 grams per liter of working solution, and most 
usually in an amount in the range from about 25 to about 40 grams per 
liter. The indazole antifoggant will generally be used in amounts of from 
about 0.01 to about 2 grams per liter of working solution, and most 
usually in an amount in the range from about 0.1 to about 0.3 grams per 
liter. The lignosulfonate will generally be used in amounts of from about 
0.001 to about 3 grams per liter of working solution, and most usually in 
an amount in the range from about 0.005 to about 0.1 grams per liter. Any 
of a wide variety of other optional ingredients can be present in the 
developing composition along with the three essential components. 
Use of a lignosulfonate is especially advantageous in hardening developers 
used in the processing of X-ray films. Such developers typically contain a 
dihydroxybenzene developing agent, such as hydroquinone, a pyrazolidone 
developing agent, such as 1-phenyl-3-pyrazolidone, a dialdehyde, such as 
glutaraldehyde bis bisulfite, which functions as a hardening agent, and an 
indazole antifoggant, such as 5-nitroindazole. In this type of developer, 
it is commonly necessary to use the 5-nitroindazole antifoggant at a 
relatively high concentration and thus the precipitation problem is a 
severe one, and the lignosulfonate is of particularly great benefit in 
alleviating the problem. 
In addition to glutaraldehyde, dialdehydes which are useful as hardening 
agents in the X-ray developers of this invention include alpha-methyl 
glutaraldehyde, beta-methyl glutaraldehyde, maleic dialdehyde, succinic 
dialdehyde, methoxy succinic dialdehyde, alpha-alpha-dimethyl 
glutaraldehyde, alpha-beta-dimethyl glutaraldehyde, methyl maleic 
dialdehyde, methyl succinic dialdehyde, alpha-methyl-beta-ethoxy 
glutaraldehyde, alpha-n-butoxy glutaraldehyde, beta-n-butyl 
glutaraldehyde, beta-isopropoxy succinic dialdehyde and butyl maleic 
dialdehyde. The dialdehyde hardening agents cann be used as such or in the 
form of bisulfite derivatives of alkali metal bisulfites, alkaline earth 
metal bisulfites, or nitrogen base bisulfites. 
In the packaging of photographic developers, it is a common practice to 
separate the components into two or more parts, often in the form of 
liquid concentrates, which are subsequently combined and diluted with 
water to form a working developing solution. This is done in order to 
avoid the tendency for deleterious chemical interactions to take place 
between certain of the components. In the practice of the present 
invention, it is a matter of choice as to which of such parts is utilized 
as the part which contains the lignosulfonate. In other words, the 
lignosulfonate can be incorporated in any of the parts, as desired. Since 
pH is a major factor affecting the tendency of the indazole antifoggants 
to precipitate, there may be no precipitation problem in the liquid 
concentrate which contains the indazole. However, where such problem does 
exist, inclusion of the lignosulfonate in the concentrate that contains 
the indazole will be effective both to avoid precipitation in the 
concentrate, and to avoid precipitation in the working developing 
solution. 
The black-and-white developing compositions described herein can be 
advantageously employed in the processing of graphic arts films or in the 
processing of X-ray films. Development of photographic elements in the 
color developer compositions described herein can be advantageously 
employed in the processing of photographic elements designed for reversal 
color processing or in the processing of negative color elements or color 
print materials. The stabilized developing compositions of the invention 
can be employed with photographic elements which are processed in color 
developers containing couplers or with photographic elements which contain 
the coupler in the silver halide emulsion layers or in layers contiguous 
thereto. The photosensitive layers present in the photographic elements 
processed according to the method of this invention can contain any of the 
conventional silver halides as the photosensitive material, for example, 
silver chloride, silver bromide, silver bromoiodide, silver chlorobromide, 
silver chloroiodide, silver chlorobromoiodide, and mixtures thereof. These 
layers can contain conventional addenda and can be coated on any of the 
photographic supports, such as, for example, cellulose nitrate film, 
cellulose acetate film, polyvinyl acetal film, polycarbonate film, 
polystyrene film, polyethylene terephthalate film, paper, polymer-coated 
paper, and the like. 
Processes employing the developer compositions of this invention can vary 
widely in regard to such features as development time and development 
temperature. Thus, for example, the development time will typically be in 
the range from about 0.2 to about 20 minutes, and more usually in the 
range from about 0.5 to about 4 minutes, while the development temperature 
will typically be in the range from about 15.degree. C. to about 
55.degree. C., and more usually in the range from about 25.degree. C. to 
about 40.degree. C. 
The stabilized developing compositions of this invention are especially 
useful in the rapid processing of X-ray film, as described, for example, 
in Barnes et al, U.S. Pat. No. 3,545,971 issued Dec. 8, 1970. 
The invention is further illustrated by the following examples of its 
practice.

EXAMPLE 1 
A black-and-white photographic developing solution (referred to hereinafter 
as Solution A) suitable for use in the processing of X-ray film was 
prepared in accordance with the following formulation: 
______________________________________ 
Component Amount (grams) 
______________________________________ 
Potassium hydroxide 29.14 
Glacial acetic acid 10.96 
Potassium sulfite 44.20 
Sodium bicarbonate 7.50 
Boric Acid 1.00 
Diethylene glycol 28.96 
Ethylenediaminetetraacetic acid 
1.67 
Carbowax 350 0.25 
5-Methylbenzotriazole 
0.06 
5-Nitroindazole 0.25 
Hydroquinone 30.00 
1-Phenyl-3-pyrazolidone 
1.50 
Glutaraldehyde 4.93 
Sodium metabisulfite 12.60 
Water to one liter 
______________________________________ 
Developing solutions B and C were also prepared and were identical to 
Solution A except that a lignosulfonate (available commercially as 
Marasperse M-22 from American Can Company) was included in Solution B at a 
concentration of 0.25 grams per liter and in Solution C at a concentration 
of 2.5 grams per liter. 
The three solutions were stored in covered glass containers at 5.degree. C. 
for a period of four weeks. Formation of a fine crystalline precipitate, 
identified by analysis as 5-nitroindazole, occurred in Solution A, whereas 
both Solution B and Solution C exhibited no precipitate formation during 
the four-week period of storage. 
EXAMPLE 2 
Example 1 was repeated using the following lignosulfonates in place of the 
Marasperse M-22: 
Orzan A at concentrations of 0.50 and 0.25 grams per liter. 
Orzan S at concentrations of 0.50 and 0.25 grams per liter. 
Lignosite 854 at concentrations of 0.50, 0.25, 0.20, 0.15, 0.10, 0.05 and 
0.01 grams per liter. 
Lignosite 458 at concentrations of 0.50, 0.25, 0.20, 0.15, 0.10, 0.05 and 
0.01 grams per liter. 
Reax 81A at concentrations of 0.50, 0.25, 0.20, and 0.15 grams per liter. 
Lignosol NSX135 at concentrations of 0.25, 0.20, 0.15, 0.10, 0.05 and 0.01 
grams per liter. 
Lignosol SF at concentrations of 0.25, 0.20 and 0.15 grams per liter. 
In every case, the lignosulfonate prevented the precipitation of the 
5-nitroindazole during the four-week period of storage at 5.degree. C. 
As shown by the above examples, the lignosulfonates effectively suppress 
the precipitation of indazole antifoggants in photographic developers. It 
should be noted that neither the wood sugars, e.g., mannose, glucose, 
xylose and galactose, nor the hemlock tannin polymers are effective for 
this purpose. Sulfonated polystyrenes, styrene-maleic anhydride 
copolymers, and carboxymethyl cellulose have also been tested and found to 
be ineffective. Thus, the ability of the lignosulfonates to solve the 
difficult problem of precipitation of indazole antifoggants is quite 
unexpected. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.