EP0753793B1

EP0753793B1 - Photographic silver halide developer composition

Info

Publication number: EP0753793B1
Application number: EP19950110914
Authority: EP
Inventors: Filippo Faranda; Sergio Aschieri; Isabelle Pastor
Original assignee: Imation Corp
Current assignee: Tulalip Consultoria Comercial SU
Priority date: 1995-07-12
Filing date: 1995-07-12
Publication date: 1999-11-17
Anticipated expiration: 2015-07-12
Also published as: EP0753793A1; DE69513391T2; JPH09101601A; DE69513391D1

Description

FIELD OF THE INVENTION

The invention relates to black-and-white photographic developing compositions comprising the combination of three different buffering agents that are stable against aerial oxidation and have excellent cleanliness during working conditions and to a process for forming a photographic image using said developing compositions.

BACKGROUND OF THE INVENTION

Black-and-white photographic elements, such as for example photographic materials useful both in X-ray radiography and in Graphic Arts, are typically processed in aqueous alkaline developing solutions containing a developing agent and a superadditive auxiliary developing agent. Examples of useful developing agents are polyhydroxybenzenes and ascorbic acids; examples of useful superadditive auxiliary developing agents are aminophenols and 3-pyrazolidones. Thus, for example, in the working examples of US 4,975,354, the developing solution comprises hydroquinone and 1-phenyl-4-hydroxymethyl-4-methyl-3-pyrazolidone and in the working examples of US 4,914,003 and 5,030,547 the developing solution comprises hydroquinone and N-methyl-p-aminophenol.
The activity of these developing agents is greatly influenced by the pH of the solution and the optimum pH range should not significantly change during the useful life of the developer composition, particularly during working conditions.
EP 622,670 discloses a developer composition having a stable pH which comprises a dihydroxybenzene developing agent, an auxiliary superadditive developing agent, an antifogging agent, an antioxidant compound, a sequestering agent and a buffering agent, said dihydroxybenzene developing agent and said buffering agent being in a molar ratio of 1:1.7 to 1.3. The buffering agent is chosen among the carbonate and borate compounds.
EP 632,323 discloses a developer composition having a pH in the range 9.0 to 11.0 and comprising a dihydroxybenzene developing agent, an aminophenol auxiliary superadditive developing agent, an antifogging agent, an antioxidant compound, a sequestering agent and a combination of buffering agents, wherein the first buffering agent is represented by carbonate compounds and the second buffering agent is selected from phosphate and borate compounds, the total amount of the first and second buffering agents being at least 35 grams per liter.
EP 196,705 discloses a high contrast developer composition comprising a dihydroxybenzene developing agent, an auxiliary superadditive developing agent, an antifogging agent, free sulfite ions in an amount of at least 5 grams per liter and a double buffering system including carbonate and borate compounds.
During the development step, a variable quantity of many different compounds is released from the processed films. That means the formation of unpleasant sludge and a dirty working solution and processor.
It could be desirable to have a developer composition which has a stable pH against aerial oxidation and which gives better cleanliness during working conditions.

SUMMARY OF THE INVENTION

The present invention relates to a black-and-white aqueous alkaline photographic developer composition comprising a developing agent, a superadditive auxiliary developing agent, an antifogging agent, an antioxidant compound, a sequestering agent and a combination of three different buffering agents, wherein the three buffering agents are represented by carbonate, borate and phosphate compounds.
The present invention also relates to a process for forming a black-and-white photographic silver image comprising the steps of imagewise exposing a silver halide photographic element and developing the exposed element with said developer composition.
The developing composition of the present invention is more stable against aerial oxidation when the developing composition is stored under room conditions in an open air storage container and gives a better cleanliness during working conditions.

DETAILED DESCRIPTION OF THE INVENTION

The developing agents employed in the aqueous alkaline developer composition of the present invention are well known and widely used in photographic processing. The developing agents can be selected from polyhydroxybenzene, aminophenol, ascorbic acid, pyrazolidone, pyrazolone, pyrimidine, dithionite, hydroxylamine and other conventional developing agents. Useful dihydroxybenzene developing agents include hydroquinone, chlorohydroquinone, bromohydroquinone, isopropylhydroquinone, tolylhydroquinone, methylhydroquinone, 2,3-dichlorohydroquinone, 2,5-dimethylhydroquinone, 2,3-dibromohydro-quinone, 1,4-dihydroxy-2-acetophenone-2,5-dimethylhydroquinone, 2,5-diethylhydroquinone, 2,5-di-p-phenethylhydroquinone, 2,5-dibenzoylhydroquinone and 2,5-diacetaminohydroquinone.
The amount of such developing agent used in the present invention is from about 0.04 to 0.70 moles per liter, preferably from 0.08 to 0.40 moles per liter.
The auxiliary developing agents showing a superadditive effect are well known in the art, as described in Mason, "Photographic Processing Chemistry", Focal Press, London 1975.
The preferred auxiliary developing agents are those described in US 5,236,816; particularly useful are the superadditive auxiliary developing agents such as aminophenols and substituted aminophenols (e.g., N-methyl-p-aminophenol, also known as Metol, and 2,4-diaminophenol) and the 3-pyrazolidone developing agents (e.g., 1-phenyl-3-pyrazolidone, also known as Phenidone, 1-phenyl-4-methyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone, also known as Dimezone S, 1-phenyl-4,4-dimethyl-3-pyrazolidone, also known as Dimezone, and 1-phenyl-4,4-dihydroxymethyl-3-pyrazolidone). Other useful 3-pyrazolidone developing agents include: 1-phenyl-5-methyl-3-pyrazolidone, 1-p-aminophenyl-4-methyl-4-propyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone, 1-m-tolyl-3-pyrazolidone, 1-p-chlorophenyl-3-pyrazolidone, 5-phenyl-3-pyrazolidone, 1-methyl-5-phenyl-3-pyrazolidone, 1-p-methoxyphenyl-3-pyrazolidone, and the like.
The amount of such superadditive auxiliary developing agent used in the present invention is from about 0.0001 to 0.15, preferably from 0.0025 to 0.1, moles per liter.
According to the present invention, a combination of carbonate, borate and phosphate compounds as buffering agents is required to prevent the pH decreasing due to the oxidation products of the developing agents and to give a better cleanliness during working conditions. The carbonate buffering agent can be sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, etc. The borate buffering agent can be boric acid, sodium borate, potassium borate, sodium tetraborate, potassium tetraborate, alkanolamine borate, such as diethanolamine borate or trietanolamine borate, and the like. The phosphate compounds can be sodium phosphate, potassium phosphate, potassium monoacid phosphate, and the like.
The amount of each of the buffering agents, carbonate, borate and phosphate compounds, is from about 0.005 to 2.0 moles per liter, preferably from about 0.01 to 1 moles per liter.
The developer composition of this invention contain an antioxidant compound to give good stability characteristics, in an amount from about 0.001 to about 1 moles per liter, preferably from about 0.08 to about 0.7 moles per liter. Useful antioxidant compounds include the sulfite preservatives, i.e. any sulfur compound capable of forming sulfite ions in aqueous solutions, such as alkali metal or ammonium sulfites, bisulfites, metabisulfites, sulfurous acid and carbonyl-bisulfite adducts. Typical examples of sulfite preservatives include sodium sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite, potassium bisulfite, lithium bisulfite, sodium metabisulfite, potassium metabisulfite, lithium metabisulfite, bisulfite formaldehyde addition compound sodium salt, and the like.
Antifoggant agents, known in the art to eliminate fog on the developed photographic silver halide films, can be used in the developer composition of this invention. They include, for example, organic antifoggant agents, such as derivatives of benzimidazole, benzotriazole, tetrazole, imidazole, indazole, thiazole, mercaptotetrazole, etc. used alone or in combination. The organic antifoggants are well known as discussed, for example, in Mees, " The Theory of the Photographic Process ", 3rd Edition, 1966, p. 344-346. Derivatives of benzotriazole are preferred in the practice of the invention, ass described in EP 182,293. Said derivatives include lower alkyl groups (having 1 to 4 carbon atoms), such as 5-methyl-benzotriazole, lower alkoxy groups (having 1 to 4 carbon atoms) or halogen (chlorine) substituted benzotriazole antifoggant agents.
At least an inorganic alkali agent is used in the developer composition of this invention to achieve a pH in the range of 9 to 12, the preferred pH range normally being above 10. The inorganic alkali agent includes KOH, NaOH, etc.
Other adjuvants well known in the art are comprised in the developer compositions of this invention. These include inorganic antifogging agents such as soluble halides (e.g., potassium or sodium bromide) and sequestering agents such as aminopolycarboxylic acid derivatives (e.g., nitriloacetic acid (NTA), ethylenediaminotetraacetic acid (EDTA), diethylenetriaminopentaacetic acid (DTPA), diaminopropanoltetraacetic acid (DPTA), triethylenetetraminohexaacetic acid, hydroxyethylenediaminotriacetic acid, ethylenediamino-N,N,N',N'-tetrapropionic acid (EDTP)), α-hydroxycarboxylic acid compounds (e.g., lactic acid), dicarboxylic acid compounds (e.g., oxalic acid and malonic acid), polyphosphate compounds (e.g., sodium hexametaphosphate) or polyphosphonic acid compounds (e.g., methylaminophosphonic acid, dimethylaminomethane diphosphonic acid, morpholino diphosphonic acid as described in US 4,873,180), and/or their salts.
Contrast promoting agents can be added to the developer composition of the present invention. Useful contrast promoting agents are, for example, those disclosed in US 4,693,456 or in US 4,777,118 having formula R₁R₂CHOH, wherein R₁ and R₂ each independently represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, or R₁ and R2 together complete a cycloalkyl ring residue.
The aliphatic groups represented by R₁ and R₂ include a straight or branched chain alkyl group of 1 to 10 carbon atoms (i.e., methyl group, ethyl group, propyl group, butyl group, etc.), a cycloalkyl group of 3 to 10 carbon atoms (i.e., cyclopentyl group, cyclohexyl group, adamantyl group, etc.), a substituted cycloalkyl group (i.e., 3-methoxypropyl group, 4-chlorocyclohexyl group, benzyl group, p-methylbenzyl group, etc.), an alkenyl group (i.e., allyl group, etc.), an alkynyl group (i.e., propargyl group, etc.).
The aromatic groups represented by R₁ and R₂ include a phenyl group, a naphthyl group including those having substituents (i.e., p-methoxyphenyl group, p-chlorophenyl group, tolyl group, etc.).
The heterocyclic groups represented by R₁ and R₂ include a 5-membered or 6-membered single ring, or a condensed ring, having at least one of oxygen, nitrogen, sulfur and selenium atoms with or without substituents (e.g., pyrroline ring, pyridine ring, quinoline ring, indole ring, oxazole ring, thiazole ring).
Preferred contrast promoting agents are, for example, methyl alcohol, ethyl alcohol, benzhydrol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanediol, methyl-phenylcarbinol and mixtures thereof.
Contrast promoting agents can be added to the developer composition in an amount from about 0.001 to about 3.0 moles per liter, preferably in an amount from about 0.01 to about 1.50 moles per liter.
The photographic developer composition of this invention can vary widely with respect to the concentration of the various ingredients included therein. Typically, the developing agent is used in an amount of from about 0.04 to about 0.70 moles per liter, preferably from about 0.08 to about 0.40 moles per liter; the superadditive auxiliary developing agent is used in an amount of from about 0.0001 to about 0.15 moles per liter, preferably from about 0.0025 to about 0.1 moles per liter; the carbonate, the borate and the phosphate buffering agents are used each in an amount of from about 0.005 to about 2.0 moles per liter, preferably from about 0.01 to about 1.0 moles per liter; the inorganic antifogging agent is used in an amount of from about 0.001 to about 0.2 moles per liter, preferably from about 0.01 to about 0.05 moles per liter; the antioxidant compound (such as the sulfite preservative) is used in an amount of from about 0.001 to about 1 moles per liter, preferably from about 0.08 to about 0.7 moles per liter; the organic antifogging compound is used in an amount of from about 1x10^-5 to about 5x10^-2 moles per liter, preferably from about 5x10^-4 to 0.01 moles per liter and the sequestering agent is used in an amount of from about 0.0001 to about 0.2 moles per liter, preferably from about 0.001 to about 0.1 moles per liter.
The pH value of the developer composition of the present invention is in the range from 9.0 to 12.0, preferably from 10.30 to 11.30.
According to the present invention, it is deemed to be significant to evaluate the stability of the developer composition of the present invention as absorbance variation (measured at 450 nm) when a sample of 50 ml developer solution is stored and stirred at 35°C in thermostatic Dubnoff bath in a 500 ml open "volumetric flask", a flat-bottomed flask with a long neck, in contact with air for significant times, for instance of one, two or three days (from a practical point of view two days and, still better, three days are a particularly significant time since they represent a week-end work stop).
Of course, both the pH of the solution and the storing temperature will affect the obtained results. The higher the values of such variables, the higher in general the measured absorbance values.
Alternatively and preferably additionally, a developer composition can be considered to be stable when its pH is stable. Generally, the pH value of a developer composition tends to increase under the above reported conditions. In the present invention, a developer composition can be considered to be unstable when after three days its pH value tends to decrease, rendering the developer composition not useful to the scope of the present invention.
The developer composition of the present invention can be usually made as single concentrated liquid part that is then diluted with water in automatic processors by the use of a mixer, to have a ready-to-use solution. A method of making a concentrated alkaline photographic developing composition packaged in a single concentrated part to be diluted with water to form a ready-to-use solution is shown, for example, in US 4,987,060.
The developer compositions of the present invention are useful in a process for treating a silver halide photographic element which can be used for any general black and white photography, Graphic Arts, X-ray, print, microfilm, color reversal (i.e., in the black and white development step of a color reversal process), and the like, as described, for example, in EP patent applications 632,323; 622,670; 618,490; 595,089; 591,747 and 581,065. They are particularly useful in a process for treating a silver halide photographic element which can be used in Graphic Arts. In particular, when contrast promoting agents as described above are contained in the developer compositions of the present invention, they are useful to treat a hard-dot photographic material, giving an image with very high contrasts and good dot quality.
The following examples illustrate the present invention.
In the examples, percentages are by weight and solutions are water solutions, unless otherwise stated.

EXAMPLE 1

Ready-to-use developer compositions (samples 1 to 8) were prepared according to the following Table 1. Comparison developer compositions 1-3 contain a double buffering system (respectively borate and phosphate compounds, borate and carbonate compounds, phosphate and carbonate compounds), while developer composition 4 (invention) contains three buffering agents (carbonate, phosphate and borate compounds).
Developer compositions 5-8 were prepared, respectively, as developer compositions 1-4, with the addition of contrast promoting agents and a higher pH value.

All the developer compositions 1-8 have the same total molar amount of buffering agents.

	1 g/l	2 g/l	3 g/l	4 g/l	5 g/l	6 g/l	7 g/l	8 g/l
Water up to liter	1	1	1	1	1	1	1	1
KOH sol.. 35 %	135	92	117	115	215	172	195	190
DTPA.Na sol. 50 %	7	7	7	7	7	7	7	7
EDTA.Na sol. 40 %	3.5	3.5	3.5	3.5	3.5	3.5	3.5	3.5
Sodium sulfite	35.75	35.75	35.75	35.75	50	50	50	50
Potassium bromide	3.3	3.3	3.3	3.3	2.5	2.5	2.5	2.5
Potassium carbonate	-	16.6	16.6	11.0	-	35.2	35.2	35.2
Boric acid	7.41	7.41	-	5.0	15.8	15.8	-	10.5
Phosphoric acid 85 %	13.75	-	13.75	9.25	29.4	-	29.4	20.0
Benzotriazole	0.2	0.2	0.2	0.2	0.07	0.07	0.07	0.07
Phenidone	0.38	0.38	0.38	0.38	-	-	-	-
Metol	-	-	-	-	2	2	2	2
Hydroquinone	15	15	15	15	20	20	20	20
Ethylene Glycole	7.5	7.5	7.5	7.5	20	20	20	20
1-Phenyl-5-mercaptotetrazole	0.03	0.03	0.03	0.03	0.04	0.04	0.04	0.04
2,2-Dimethyl-1,3-propane diol	-	-	-	-	5	5	5	5
Benzhydrol	-	-	-	-	0.1	0.1	0.1	0.1
pH at 20°C	10.60	10.60	10.60	10.60	10.90	10.90	10.90	10.90

Developer compositions 1 to 8 were checked through the following test: samples of 500 ml of each developer were put into an open glass calibrated flask (capacity 5000 ml) and the oxidation test through a continuous air contact was made in stressed conditions by the use of Dubnoff thermostatic bath at 35°C and constant agitation for 8 hours/day. At regular intervals, pH at 20°C and absorbance at 450 nm were measured. A developer composition is considered useful against aerial oxidation when it shows good results both considering the pH test and the absorbance test.

The values of the pH and of the absorbance at 450 nm for the developer compositions stored for different hours are respectively reported hereinbelow in Tables 2 and 3.

Developer Compositions	pH values
	Fresh	24 hours	48 hours	72 hours	Results
1 (comparison)	10.60	11.46	11.92	12.47	good
2 (comparison)	10.60	11.94	12.48	11.70	bad
3 (comparison)	10.60	11.40	11.81	12.25	good
4 (invention)	10.60	11.50	11.94	12.50	good
5 (comparison)	10.90	11.63	12.06	12.41	good
6 (comparison)	10.90	12.05	12.48	11.98	bad
7 (comparison)	10.90	11.56	11.95	12.31	good
8 (invention)	10.90	11.70	12.12	12.45	good

Developer Compositions	Absorbance
	Fresh	24 hours	48 hours	72 hours	Results
1 (comparison)	0.0024	0.2150	0.8048	2.1556	good
2 (comparison)	0.0021	0.3722	1.4467	> 3	bad
3 (comparison)	0.0030	0.2142	0.7154	2.1415	good
4 (invention)	0.0026	0.2008	0.8542	2.1820	good
5 (comparison)	0.0022	0.4140	0.8648	2.5560	good
6 (comparison)	0.0020	0.5985	1.9630	> 3	bad
7 (comparison)	0.0026	0.3814	0.8482	2.4215	good
8 (invention)	0.0024	0.4518	0.9854	2.7505	good

Tables 2 and 3 show that comparison developer compositions 2 and 6, containing a double buffering system (carbonate and borate), give results not acceptable, related to the stability of both pH and the absorbance values. In fact, the pH values of developer compositions 2 and 6 measured after 72 hours are lower than the same values measured after 48 hours, rendering the developer compositions not useful. In addition, the absorbance values of developer compositions 2 and 6 measured after 72 hours are higher than 3, that means that they have reached a very dark coloration. Developer compositions having such high absorbance value are not useful to the scope of the present invention. All the other developer compositions give good results related to both pH and absorbance test.
Strips of a Graphic Arts 3M EDG IR Film (Film 1) were prepared comprising a chlorobromide emulsion AgBr_0.02Cl_0.98 of narrow grain size distribution and mean grain size of 0.20 micrometers, prepared by the conventional double jet procedure and coated onto a subbed polyester base at a silver coverage of 4.2 grams per square meter. The film also comprised a Blue Green filter. The strips were exposed to an infrared laser diode at 784 nm. Sensitometric tests were made by developing the exposed strips at a temperature of 35°C and development time of 51 seconds using developer compositions 1-4 in a Durr-Processor 260 Type, a developing processor made by Durr-Dental Gmbh & Co.KG., then fixing at a temperature of 35°C and fixing time of 51 seconds in a 3M Fix-Roll fixing solution. In total, 8 square meters of 3M EDG IR Film were processed in each developer composition. At the end of the processing step of each square meter of film, the maximum density values were measured. The results are shown in Table 4.

The turbidity of the developer compositions 1-4 and the cleanliness of the processor, after removal of the developer compositions 1-4 at the end of the work, were also measured by a Hach Ratio/XR turbidimeter. The results are shown in Table 5.

Developer Composition	Dmax values square meters of processed film
	1	2	3	4	5	6	7	8	Results
1 (comparison)	5.70	5.55	5.30	5.00	4.70	4.30	3.85	3.60	bad
2 (comparison)	5.75	5.75	5.55	5.40	5.35	5.00	4.80	4.60	good
3 (comparison)	5.75	5.70	5.45	5.20	5.10	4.75	4.50	4.25	good
4 (invention)	5.75	5.70	5.50	5.25	5.15	4.85	4.60	4.35	good

Developer Compositions	Turbidity	Deposit and sludge	Results
1 (comparison)	48	NO	good
2 (comparison)	30	NO	good
3 (comparison)	105	YES	bad
4 (invention)	32	NO	good

Table 4 shows that comparison developer composition 1, containing a double buffering system (phosphate and borate), is not useful because it shows poor sensitometric characteristics during working conditions. In fact, when only 6 square meters of film were processed, the Dmax value obtained by treating the material with developer composition 1 falls under 4.00, a value that is a not acceptable.
Table 5 shows that comparison developer composition 3, containing a double buffering system (phosphate and carbonate), is not useful because it shows high turbidity values and formation of sludge and deposit at the end of the work.
The results shown in Tables 2 and 3, respectively related to the stability against aerial oxidation of pH and absorbance values, combined with the results shown in Table 4 and 5, respectively related to the sensitometric characteristics and to the turbidity and cleanliness of the developer compositions, show that only the developer composition 4 of the present invention (containing carbonate, phosphate and borate as buffering agents) presents all good results.

EXAMPLE 2

Strips of a Graphic Arts hard-dot silver halide film containing a hydrazine compound (Film 2) were exposed by a laser diode at 633 nm and developed as Film 1 (as described in Example 1), using developer compositions 5-8. Then, 8 square meters of Film 2 were processed. At the end of the processing step of each square meter of film, the Θ₂ contrast values, corresponding to the absolute value of the slope of the line joining the density points of 1.60 and 4.00, were measured. The results are shown in Table 6.

As described in Example 1, the turbidity of the developer compositions 5-8 and the cleanliness of the processor, after removal of the developer compositions 5-8 at the end of the work, were also measured by a Hach Ratio/XR turbidimeter. The results are shown in Table 7.

Developer Composition	Θ₂ contrast values square meters of processed film
	1	2	3	4	5	6	7	8	Results
5 (comparison)	33.2	24.7	21.9	18.6	18.0	17.6	17.5	16.2	bad
6 (comparison)	33.2	28.8	26.2	24.1	22.2	21.6	20.8	20.4	good
7 (comparison)	33.1	28.5	24.4	23.2	21.0	20.8	20.1	20.0	good
8 (invention)	33.3	28.7	25.7	23.7	21.3	21.1	20.4	20.1	good

Developer Compositions	Turbidity	Deposit and sludge	Results
5 (comparison)	51	NO	good
6 (comparison)	36	NO	good
7 (comparison)	123	YES	bad
8 (invention)	41	NO	good

Table 6 shows that comparison developer composition 5, containing a double buffering system (phosphate and borate), is not useful because it shows poor sensitometric characteristics during working conditions. In fact, when only 3 square meters of film were processed, the Θ2 contrast value obtained by treating the material with developer composition 5 falls under 20.0, a value that is not acceptable.
Table 7 shows that comparison developer composition 7, containing a double buffering system (phosphate and carbonate), is not useful because it shows high turbidity values and formation of sludge and deposit at the end of the work.
The results shown in Tables 2 and 3, respectively related to the stability against aerial oxidation of pH and absorbance values, combined with the results shown in Table 6 and 7, respectively related to the sensitometric characteristics and to the turbidity and cleanliness of the developer compositions, show that only the developer composition 8 of the present invention (containing carbonate, phosphate and borate as buffering agents) presents all good results.

Claims

Black-and-white aqueous alkaline photographic developer composition comprising:

a) a developing agent in an amount of from about 0.04 to about 0.70 moles per liter;

b) a superadditive auxiliary developing agent in an amount of from about 0.0001 to about 0.15 moles per liter;

c) an inorganic antifogging agent in an amount of from about 0.001 to about 0.2 moles per liter;

d) an organic antifogging agent in an amount of from about lx10^-5 to about 5x10^-2 moles per liter;

e) an antioxidant compound in an amount of from about 0.001 to about 1 moles per liter;

f) a sequestering agent in an amount of from about 0.0001 to about 0.2 moles per liter;

g) an inorganic alkali agent to have a pH in the range 9 to 12; and

h) a combination of three different buffering agents, each used in an amount of from about 0.005 to about 2.0 moles per liter,

wherein the three buffering agents are represented by carbonate, borate and phosphate compounds.
Black-and-white aqueous alkaline photographic developer composition of claim 1 wherein the developing agent is hydroquinone.
Black-and-white aqueous alkaline photographic developer composition of claim 1 wherein the superadditive auxiliary developing agent is a 3-pyrazolidone derivative.
Black-and-white aqueous alkaline photographic developer composition of claim 1 wherein the superadditive auxiliary developing agent is an amino phenol derivative.
Black-and-white aqueous alkaline photographic developer composition of claim 1 wherein the carbonate buffering agent is used in an amount of from about 0.01 to about 1.0 moles per liter.
Black-and-white aqueous alkaline photographic developer composition of claim 1 wherein the borate buffering agent is used in an amount of from about 0.01 to about 1.0 moles per liter.
Black-and-white aqueous alkaline photographic developer composition of claim 1 wherein the phosphate buffering agent is used in an amount of from about 0.01 to about 1.0 moles per liter.
Black-and-white aqueous alkaline photographic developer composition of claim 1 comprising at least a contrast promoting agent having formula :
wherein R₁ and R₂ each independently represents a hydrogen atom, an aliphatic group, an aromatic group, a heterocyclic group, or R₁ and R₂ together complete a cycloalkyl ring residue.
Process for forming a black-and-white photographic silver image comprising the steps of (1) imagewise exposing a silver halide photographic element And (2) developing the exposed element, said developing being effected with the black-and-white aqueous alkaline photographic developer composition of claim 1.