FIELD OF THE INVENTION
[0001] The present invention relates to a photographic developer, more specifically a developer
for a silver halide photographic light-sensitive material capable of forming an image
of high sensitivity and high density without silver sludge formation therein even
when processed at low replenishing rates.
BACKGROUND OF THE INVENTION
[0002] Sulfites such as sodium sulfite and potassium sulfite, used as antioxidants for photographic
developers, have an ability dissolving silver halide.
[0003] This results in the formation of a large amount of a sulfite-silver complex salt
upon light-sensitive material processing, which complex salt elutes in the developer.
The eluted silver complex is easily reduced by the developing agent, resulting in
the accumulation of precipitated silver known as silver sludge.
[0004] In continuous processing using an automatic processing machine, this silver sludge,
in suspension in the developer, adheres to the film and the rollers and belts of the
automatic processing machine.
[0005] This can cause serious failures such as yellow-brown streak stains and flaws on the
film being transported.
[0006] In recent years, processing solution retention in developing machine tanks has increased
as the photographic processing solution replenishing rate has been reduced to meet
the requirements related to environmental conservation. Thus the amount of silver
sludge accumulated has increased.
[0007] Traditionally, there have been proposed a large number of arts for prevention of
silver sludge, including Japanese Patent Publication Open to Public Inspection (hereinafter
referred to as Japanese Patent O.P.I. Publication) No. 114035/1983, using a thiouracil,
Japanese Patent O.P.I. Publication No. 2043/1988, using a mercaptobenzoic acid, Japanese
Patent Examined Publication No. 14953/1972, using an aliphatic mercaptocarboxylic
acid, Japanese Patent O.P.I. Publication No. 178959/1987, Japanese Patent O.P.I. Publication
No. 51844/1991, using a disulfide, Japanese Patent O.P.I. Publication No. 26136/1971,
using a sulfur-containing a-amino acid, and various mercaptoazoles, all of which are
compounds likely to form a water-soluble silver salt.
[0008] However, many of these compounds have the following drawbacks, and few are satisfactory
from the viewpoint of practical use.
1) Air oxidation degrades the sludge preventing effect of the compounds in the developer.
2) Large amounts must be used to obtain the desired sludge preventing effect.
3) Use in large amounts deteriorates film sensitivity and gamma value.
4) Malodor is generated.
5) Expensive for processing solutions.
[0009] There has been strong demand for the development of a new art free of these drawbacks.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide a developer which allows easy
obtainment of an image of excellent finish quality without silver sludge formation,
photographic developer stain and roller/belt stain even when used at low replenishing
rates in continuous processing of a large amount of light-sensitive material using
an automatic processing machine.
[0011] It is another object of the present invention to provide a silver halide photographic
light-sensitive material developer having a sludge-preventing effect without affecting
the photographic performance. The other objects of the present invention will become
obvious through the following description.
[0012] The above objects of the present invention are accomplished by the present invention
described as follows:
[0013] The objects are accomplished by a developer for developing silver halide photographic
light-sensitive material which contains a compound represented by the following formula
1 or 2:

wherein R
1 and R
2 independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
R
1 and R
2 are not hydrogen atoms at the same time. R
3 and R
4 independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms;
R
5 represents a hydroxyl group, an amino group or an alkyl group having 1 to 3 carbon
atoms. R
6 and R
7 independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms,
an acyl group having up to 18 carbon atoms or a -COOM
2 group. R
6 and R
7 are not hydrogen atoms at the same time. M
1 represents a hydrogen atom, an alkali metal atom or an ammonium group, and m represents
0, 1 or 2. M
2 is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkali metal atom,
an aryl group or an aralkyl group having not more than 15 carbon atoms.
[0014] The present invention is described in detail below. Alkyl groups having 1 to 4 carbon
atoms as described above include a methyl group, an ethyl group, a propyl group and
a butyl group.
[0015] Examples of acyl groups having up to 18 carbon atoms include an acetyl group and
a benzoyl group. Examples of aralkyl groups having up to 15 carbon atoms include a
benzyl group and a phenetyl group. Aryl groups include a phenyl group and a naphthyl
group.
[0016] Examples of alkali metal atoms for M
1 include sodium ion and potassium ion.
[0017] Although various methods of synthesis can be used to synthesize the above compounds
of the present invention, Strecker's method of amino acid synthesis, known to be an
amino acid synthesis method, can be used, wherein amino acid acetylation is achieved
by alternate addition of alkali and acetic anhydride in an aqueous solution.
[0019] The above compounds of the present invention may be used singly or in combination.
It is also acceptable to use in combination at least one kind of the compound of formula
1 and at least one kind of the compound of formula 2.
[0020] The inventive compounds of formulas 1 and 2 are used in amounts of 1 x 10-
s to 3 x 10-
2 mol, preferably 1 x 10-
4 to 1 x 10-
2 mol per liter of developer. The replenishing rate for the developer containing a
compound of the present invention is normally 0.05 to 0.65 I, preferably 0.10 to 0.35
I per m
2 of light-sensitive material, though it varies depending on the kinds of light-sensitive
material, automatic processing machine, and other factors.
[0021] Preferably, the developing through drying processes are completed within 90 seconds
when an automatic processing machine capable of developing, fixing and washing or
stabilizing is used to process a silver halide light-sensitive material relating to
the present invention.
[0022] In otherwords, the time from initiation of immersion of the tip of the light-sensitive
material in the developer, via the various processes, to discharge of the same tip
from the drying zone (what is called "dry to dry time") is preferably not longer than
90 seconds, more preferably not longer than 60 seconds.
[0023] Fixing temperature and time are preferably about 20 to 50°C and 6 to 20 seconds,
more preferably 30 to 40°C and 6 to 15 seconds.
[0024] When the developer of the present invention is used, developing time is normally
5 to 45 seconds, preferably 8 to 30 seconds, and developing temperature is preferably
25 to 50°C, more preferably 30 to 40°C.
[0025] Drying may be achieved by hot air blow at normally 35 to 100°C, preferably 40 to
80°C. Alternatively, a drying zone equipped with a far infrared heating means may
be arranged in the automatic processing machine.
[0026] The automatic processing machine may be equipped with a mechanism for adding eitherwateror
an acidic rinsing solution having no fixing capability to the light-sensitive material,
among the above developing, fixing and washing processes such described as in Japanese
Patent O.P.I. Publication No. 264953/199. The automatic processing machine may also
have therein equipment for preparing developers and fixers.
[0027] The developer of the present invention preferably contains as a developing agent
a 1,4-dihydroxybenzene compound or, if necessary, a p-aminophenol compound and/or
a pyrazolidone compound.
[0028] 1,4-dihydroxybenzenes include hydroquinone, chlorohydroquinone, bromohydroquinone,
isopropylhydroquinone, methylhydroquinone, 2,3-dichlorohydroquinone, 2,5-dichlorohydroquinone,
2,3-dibromohydroquinone, 2,5-dimethylhydroquinone and hydroquinone monosulfonate,
with preference given to hydroquinone. p-aminophenol-based developing agents include
N-methyl-p-aminophenol, p-aminophenol, N-((3-hydroxyethyl)-p-aminophenol, N-(4-hydroxyphenyl)glycine,
2-methyl-p-aminophenol and p-benzylaminophenol, with preference given to N-methyl-p-aminophenol.
[0029] Examples of pyrazolidone compounds which can be used in the present invention include
1-phenyl-3-pyrazolidone, 1-phenyl-4,4-dimethyl-3-pyrazolidone, 1-phenyl-4-ethyl-3-pyrazolidone,
1-phenyl-5-methyl-3-pyrazolidone, 1-phenyl-4-methyl-3-pyrazolidone, 1-phenyl-4-methyl-4-hydroxymethyl-3-pyrazolidone,
1-phenyl-4,4-dihydroxymethyl-3-pyrazolidone, 1,5-diphenyl-3-pyrazolidone, 1-p-tolyl-3-pyrazolidone,
1-phenyl-2-acetyl-4,4-dimethyl-3-pyrazolidone, 1-p-hydroxyphenyl-4,4-dimethyl-3-pyrazolidone,
1-(2-benzothiazolyl)-3-pyrazolidone and 3-acetoxy-1-phenyl-3-pyrazolidone.
[0030] The amount of 1,4-dihydroxybenzene added is 0.01 to 0.7 mol, preferably 0.1 to 0.5
mol per liter of developer.
[0031] The amounts of p-aminophenol compound and pyrazolidone compound added are 0.0005
to 0.2 mol, preferably 0.001 to 0.1 mol per liter of developer.
[0032] Examples of sulfites used in the developer of the present invention include sodium
sulfite, potassium sulfite, lithium sulfite, ammonium sulfite, sodium bisulfite and
potassium metasulfite. The amount ofthese sulfites used is 0.1 to 2.0 mol, preferably
0.1 to 1.0 mol per liter of developer. Also, the upper limit is preferably 3.0 mol
per liter of developer for a concentrated developer.
[0033] The developer may contain a chelating agent having an iron ion chelating stability
constant of over 8. The iron ion mentioned herein is ferricion (Fe
3+).
[0034] Chelating agents having an iron ion chelating stability constant of over 8 include
organic carboxylic acid chelating agents, organic phosphoric acid chelating agents,
inorganic phosphoric acid chelating agents and polyhydroxyl compounds.
[0035] Specifically, such chelating agents include ethylenediamine-di-o-hydroxyphenylacetic
acid, triethylenete- tramineacetic acid, diaminopropanetetraacetic acid, nitrilotriacetic
acid, hydroxyethylethylenediaminetriacetic acid, dihydroxyethylglycine, ethylenediaminediacetic
acid, ethylenediaminedipropionic acid, iminodiacetic acid, diethylenetriaminepentaacetic
acid, hydroxyethyliminodiacetic acid, 1,3-diamino-2-propanoltetraacetic acid, transcyclohexanediaminetetraacetic
acid, ethylenediaminetetraacetic acid, glycol ether amine tetraacetic acid, ethylenediamine-N,N,N',N'-tetrakismethylenephosphonic
acid, nitrilo-N,N,N-trimethylenephosphonic acid, 1-hydroxyethyiidene-1,1-diphosphonicacid,
1,1-diphosphonoethane-2-carboxylicacid, 2-phosphonobutane-1,2,4-tricarboxylic acid,
1-hydroxy-1-phosphonopropane-1,2,3-tricarboxylic acid, catechol-3,5-disulfonic acid,
sodium pyrophosphate, sodium tetrapolyphosphate and sodium hexametaphosphate.
[0036] The developer of the present invention may contain a hardener which enhances the
film physical properties by reacting with the gelatin in the light-sensitive material
during the developing process. Examples of hardeners include glutaraldehyde, a-methylglutaraldehyde,
(3-methylglutaraldehyde, maleic dialdehyde, succinic dialdehyde, methoxysuccinic dialdehyde,
methylsuccinic dialdehyde, α-methoxy-β-ethoxyglutaraldehyde, an-butoxyglutaraldehyde,
a,a-dimethoxysuccinic dialdehyde, β-isopropylsuccinic dialdehyde, a,a-diethylsuccinic
dialdehyde, butylmaleic dialdehyde and bisulfite adducts thereof.
[0037] In addition to these components, the developer may further contain developing inhibitors
such as sodium bromide and potassium iodide, organic solvents such as ethylene glycol,
diethylene glycol, triethylene glycol, dimethylformamide, methyl cellosolve, hexylene
glycol, ethanol and methanol, mercapto compounds such as 1-phenyl-5-mercaptotetrazole
and sodium 2-mercaptobenzimidazole-5-sulfonate, and antifoggants such as 5-methylbenzotriazole
and other benzotriazole compounds. Other additives such as toning agents, surfactants,
defoaming agents may also be added as necessary.
[0038] The pH of the developer is normally 9.0 to 12, preferably 9.0 to 11.5. Examples of
the alkali or buffer used for pH adjustment include pH regulators such as sodium hydroxide,
potassium hydroxide, sodium carbonate, potassium carbonate, boric acid, sodium tertiary
phosphate and potassium tertiary phosphate.
[0039] A fixer for fixing the light sensitive material may contain a fixing agent such as
sodium thiosulfate or ammonium thiosulfate, with preference given to ammonium thiosulfate
from the viewpoint of fixing speed. These fixing agents are usually used in amounts
of about 0.1 to 6 mol/liter.
[0040] The fixer may also contain a water-soluble aluminum salt as a hardener, such as aluminum
chloride, aluminum sulfate or potassium alum.
[0041] The fixer may incorporate malic acid, tartaric acid, citric acid, gluconic acid and
derivatives thereof, singly or in combination. These compounds are effective when
contained at not less than 0.001 mol per liter of fixer, with a greater effect obtained
at 0.005 to 0.03 mol per liter of fixer.
[0042] Fixer pH is normally not lower than 3.8, preferably 4.2 to 7.0. In view of hardening
in the fixer, sulfurous acid gas odor the pH is more preferably 4.3 to 4.8.
[0043] Silver halide photographic light-sensitive material emulsions to which the present
invention is applicable include medical radiographic materials, photographic materials
for printing plate making and direct positive photographic materials.
[0044] The silver halide photographic light-sensitive material to which the present invention
is applied may be comprised a silver halide such as silver iodobromide, silver iodochloride
or silver iodochlorobromide, with preference given to silver iodobromide from the
viewpoint of high sensitivity.
[0045] Emulsions for the silver halide photographic light-sensitive material include monodispersed
grains of high inner iodine content such as those disclosed in Japanese Patent O.P.I.
Publication Nos. 177535/1984, 802237/1986, 132943/1986 and 49751/1988. Crystalline
habit may be cubic, tetradecahedral or octahedral, and intermediate (111) and (100)
planes may be present in any ratio.
[0046] The emulsion may be of tabular grains having an aspect ratio of not less than 2.
Such tabular grains have advantages such as improvements in spectral sensitizing efficiency,
image granularity and sharpness, and are disclosed in British Patent No. 2,112,157,
US Patent Nos. 4,439,520,4,433,048,4,414,310 and 4,434,226, and Japanese Patent O.P.I.
Publication Nos. 113927/1983, 127921/1983, 138342/1988, 284272/1988 and 305343/1988.
The emulsion can be prepared as described in these publications.
[0047] Additives and other substances used in the silver halide photographic light-sensitive
material include those described in Research Disclosure Nos. 17643 (December, 1978),
18716 (November, 1979) and 308119 (December, 1989) (hereinafter referred to as RD17643,
RD18716 and RD308119, respectively). The following table shows where they are described.

EXAMPLES
Example 1
Preparation of emulsions A, B and C
1) Preparation of seed emulsion
[0048] While maintaining a temperature of 60°C, a pAg of 8 and a pH of 2.0, monodispersed
cubic grains of silver iodobromide having an average grain size of 0.3 µm and a silver
iodide content of 2 mol% were prepared by the double jet method.
[0049] The resulting reaction mixture was desalinized at 40°C, using an aqueous solution
of Demol-N (produced by Kao Atlas) and an aqueous solution of magnesium sulfate, after
which it was re-dispersed in an aqueous gelatin solution, to yield a seed emulsion.
2) Grain growth from seed emulsion
[0050] Using the above seed emulsion, grains were grown as follows: First, the seed emulsion
was dispersed in an aqueous gelatin solution being kept at 40°C, and aqueous ammonia
and acetic acid were added to obtain a pH of 9.7. An aqueous solution of ammoniacal
silver nitrate and an aqueous solution of potassium bromide and potassium iodide were
then added to the dispersion by the double jet method, while maintaining a pAg of
7.3 and a pH of 9.7, to yield a layer containing 35 mol% silver iodide. Next, another
aqueous solution of ammoniacal silver nitrate and an aqueous solution of potassium
bromide were added by the double jet method.
[0051] Until 95% of the desired grain size was reached, the pAg was kept at 9.0, with the
pH varied continuously over the range of 9.0 to 8.0. The pAg was then changed to 11.0,
and while keeping the pH at 8.0, grains were grown up to the desired grain size. Subsequently,
acetic acid was added to obtain a pH of 6.0, after which 400 mg of the anhydride of
5,5'-dichloro-9-ethyl-3,3'-di(3-sulfopropyl)oxacarbocyanine sodium salt was added
per mol of silver halide. This mixture was then desalinized with the above aqueous
solution of Demol-N and aqueous solution of magnesium sulfate, and then re-dispersed
in a gelatin solution.
[0052] Monodispersed silver iodobromide emulsions A, B and C, comprising tetradecahedral
grains with round tips having an average silver iodide content of 2.0 mol%, were thus
prepared, which had average grain sizes of 0.40, 0.65 and 1.00 µm and variation coefficients
of grain size distribution (a/r) of 0.17, 0.16 and 0.16, respectively, in which σ
is the standard deviation of grain size distribution and r is the average grain size.
Preparation of emulsion D
1) Preparation of seed emulsion
[0053] A hexagonal tabular seed emulsion was prepared as follows:

[0054] After stopping the addition of solutions Band C, the temperature of solution A was
increased to 60°C over a period of 60 minutes, and solutions B and C were again added
by the double jet method at a flow rate of 68.5 ml/min over a period of 50 minutes,
while keeping the silver potential (determined using a silver ion selective electrode
in combination with a saturated silver-silver chloride electrode as a reference electrode)
at +6 mV using solution D.
[0055] After completion of the addition, 3% KOH solution was added to obtain a pH of 6,
followed by immediate desalinization and washing. The resulting emulsion was designated
as seed emulsion Em 0. Electron microscopy revealed that this emulsion comprised hexagonal
tabular silver halide grains not less than 90% by projected area of which had a ratio
of the largest edge length to the shortest edge length of 1.0 to 2.0 and which tabular
grains had an average thickness of 0.07 µm and an average diameter of 0.5 µm as of
circle diameter.
[0056] Using the following four solutions, a tabular silver iodobromide emulsion D containing
1.53 mol% Agl was prepared.

[0057] Throughout this operation, the silver potential was kept at +25 mV using solution
D. After completion of the addition, the following spectral sensitizing dyes A and
B were added in amounts of 300 mg and 15 mg, respectively, per mol of silver halide.
[0058] After the excess salts were removed by precipitation and desalinization with the
same aqueous solutions of Demol-N and of magnesium sulfate as above, an aqueous solution
of 92.2 g of ossein gelatin was added, and the mixture was stirred and re-dispersed.
[0059] A tabular silver iodobromide emulsion D having an average silver iodide content of
1.5 mol%, a projected area diameter of 0.96 µm, a coefficient of variation of 0.25
and an aspect ratio of 4.0 was thus prepared.
Sensitizing dye A: Anhydride of 5,5'-dichloro-9-ethyl-3,3'di-(3-sulfopropyl)oxacarboxycyanine
sodium salt
Sensitizing dye B: Anhydride of 5,5'-di-(butoxycarbonyl)1,1'-diethyl-3,3'-di-(4-sulfobutyl
)benzimidazolocarbocyanine sodium salt
Sample preparation
[0060] To each of the thus-obtained emulsions A, B, C and D, a 200:1 (w/w) mixture of the
above sensitizing dyes A and B was added at 975 mg, 600 mg, 390 mg and 500 mg per
mol of silver halide, respectively.
[0061] Ten minutes later, appropriate amounts of chloroauric acid, sodium thiosulfate and
ammonium thiocyanate were added for optimum chemical sensitization. Fifteen minutes
before completion of ripening, 200 mg of potassium iodide was added per mol of silver
halide. Subsequently, 3 x 10-
2 mol of 4-hydroxy-6-methyl-1,3,3a,7-tetrazaindene was added per mol of silver halide,
and this mixture was dispersed in an aqueous solution of 70 g of gelatin.
[0062] Of the four ripened emulsions, A, B and C were mixed in a weight ratio of 15:65:20,
to yield emulsion I, while emulsion D, designated as emulsion II, was used as such.
[0063] To each emulsion, the following additives were added. The amounts of addition are
shown per mol of silver halide.

Preparation of dye dispersion
[0064] Ten Kilograms of the following dye was dissolved in a mixed solvent of 28 I of tricresyl
phosphate and 85 I of ethyl acetate at 55°C. This solution is designated as the oily
solution.
[0065] Separately, 270 I of a 9.3% aqueous solution of gelatin containing 1.35 kg of an
anionic surfactant AS was prepared. This solution is designated as the aqueous solution.
Next, the oily solution and the aqueous solution were placed in a dispersing vessel
and dispersed while keeping the liquid temperature at 40°C. To the resulting dispersion
were added appropriate amounts of phenol and 1,1-dimethylol-bromo-1-nitromethane,
and water was added to 240 kg.

[0066] The composition of the protective layer are as follows The amount of addition are
shown per liter of coating solution.

[0067] The resulting coating solution was coated and dried uniformly on a blue-colored subbed
polyethylene terephthalate film base 180 µm thick.
[0068] Using two slide hopper coaters, both the emulsion layer and the protective layer
were coated simultaneously at a coating speed of 90 m per minute, to yield samples,
wherein coating rates were 1.7 g/m
2 as of silver for the emulsion layer and 0.99 g/m
2 as of gelatin for the protective layer.
[0069] In Table 1, developing sample 1 was obtained from emulsion I, and developing sample
2 obtained from emulsion II.
[0070] The compositions of the developer and fixer used in the present invention are as
follows:

[0071] To prepare the developer, parts A and B were added at the same time to about 5 liters
of water, and while stirring and dissolving the mixture, water was added to 12 liters,
and glacial acetic acid was added to obtain a pH of 10.40, to yield a developer replenisher.
[0072] To this developer replenisher, the above starter was added at 20 ml/I, followed by
pH adjustment to 10.26 before use.
[0073] To prepare the fixer, parts A and B were added at the same time to about 5 liters
of water, and while stirring and dissolving the mixture, water was added to 18 liters,
and sulfuric acid or NaOH were added to obtain a pH of 4.4, to yield a fixer replenisher.
[0074] Based on the above developer compounds of the present invention and comparative compounds
were added as listed in Table 1 below to prepare developers, which were used for actual
developing.
[0075] The following Comparative Compounds 1 - 12 were used as comparative compounds.
Comparative Compound 1: L-cysteine (free base)

Comparative Compound 2: Cystine

Comparative Compound 3: L-methionine

Comparative Compound 4: DL-penicillamine

Comparative Compound 5: Acetylmethionine

Comparative Compound 6: DL-ethionine

Comparative Compound 7: Mercaptoisobutyric acid

Comparative Compound 8: β-phenyl-α-mercaptoacrylic acid

Comparative Compound 9: y-isothioureidobutyric acid

Comparative Compound 10: N-acetyl-L-cysteine

Comparative Compound 11: Homocysteine

Comparative Compound 12: Isoleucine

[0076] Developing was conducted using the roller transport automatic processing machines
described below.

[0077] Processing temperatures were 35°C for developing, 33°C for fixation, 20°C for washing
and 50°C for drying.
[0078] The samples were evaluated as follows:
1. Sensitometry
[0079] The sample, inserted between two sheets of fluorescent sensitizing paper KO-250,
manufactured by Konica Corp., was subjected to exposure through an aluminum wedge
of at a tube voltage of 80 kV, a tube amperage of 100 mAand an irradiation time of
50 msec, after which it was processed using the above automatic processing machines.
With respect to the processed sample, the reciprocal of the exposure amount required
to obtain a density of base density + fog density + 1.0 was calculated as a percent
sensitivity relative to the sensitivity of sample No. 1 processed with the above developer
and fixer of basic composition using automatic processing machine No. 2 (experiment
No. 15).
[0080] The density in the unexposed portion of the exposed sample was determined using Konica
PDA-65 densitometer, and the base density was subtracted therefrom to obtain the fog
density, and the maximum density was expressed as Dm.
2. Silver sludge evaluation
[0081] Next, developing samples, subjected to X-ray exposure to a density of 1.0 over the
entire surface of the sample, were processed at a fixer replenishing rate of 300 cc/m
2 at 70 sheets per day for 30 consecutive days, using the above-described automatic
processing machine Nos. 1, and 3, wherein the developer replenishing rate and developing
sample were changed as shown in Table 1.
[0082] The developing samples used were the above sample Nos. 1 and 2.
[0083] Upon processing, visual evaluation was made for possible stains on the developing
rack, rollers and wall, and of the processed sample, in the following four grades:
A: Almost no silver sludge seen, with no stain on the rollers or wall.
B: Developer turbidity seen, with slight stain on the processing tank wall.
C: Silver sludge seen, with developing rack stain difficult to wash down.
D: Much silver sludge seen on the developer tank, causing image stain as a result
of its adhesion to the film being processed.
3. Evaluation of residual silver
[0084] The above sample No. 2 was processed unexposed and evaluated for residual silver
as follows:
One drop of a 2.6 x 10-3 mol/I aqueous solution of sodium sulfide, as the residual silver evaluating solution,
was dropped on a surface of the above residual silver evaluating film. Three minutes
later, the solution was thoroughly wiped away, and the film was kept standing at normal
temperature and normal humidity for 15 hours.
[0085] Then, using a PDA-65 densitometer (produced by Konica Corporation), blue light transmission
densities were determined for the portion where the residual silver evaluating solution
was dropped and the other portion. The difference of the densities was used as the
index of residual silver. The residual silver concentration in the processed film
increases as this difference increases.
[0087] As seen in these tables, according to the present invention, silver sludge is well
prevented without photographic performance deterioration even at reduced developer
replenishing rates.
[0088] Specifically, Table 1 shows that the addition of a compound of the present invention
to the developer did not lower the sensitivity or Dm (maximum density), while the
addition of a comparative compound significantly lowered the sensitivity, though it
had a slight preventive effect on silver sludge at high replenishing rates.
[0089] Results of experiment Nos. 1 through 10 demonstrate that developers containing a
compound of the present invention remain excellently effective without deterioration
of the silver sludge preventing effect even when the replenishing rate is reduced
to 200 ml/m
2. Also, the results of experiment Nos. 12 and 14 demonstrate that there is no difference
in silver sludge preventing effect among different automatic processing machines.
[0090] An unexpected finding is that the present invention offers improved fixing performance
with no residual silver.