Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
12~4~Z5
IMAGE STABILIZER FOR SILVER HALIDE
PHOTOGRAPHIC MATERIAL
FIELD OF THE INVRNTION
The present invention relates to an image stabilizer for
use in the processing of a silver halide photographic material.
More particularly, the invention relates to an ima~e stabilizer
that prevents the unexposed area of the photographic material
from staining during storage after processing.
BACRGROUND OF THE INVENTION
. _
A silver halide photographic material is processed by a
sequence of imagewise exposure, color development and desilvering
to form a dye image as well as reduced silver. The reduced
silver is oxidized by a bleaching agent and is converted to a
soluble silver complex upon treatment with a fixing agent and
is washed away with water. The dye image is subse~uently
subjected to a stabilization step. But during extended storage,
the dye image fades away and the white unexposed area turns
yellow (hereunder referred to as yellow stain), and in either
case, the viewing of the picture is obstructed. Of the two
defects, yellow stain is known to be more conspicuous and
occurs very rapidly when the photographic material is stored
under strong illumination or hot and humid conditions. It
has therefore been strongly desired to prevent the premature
occurrence of yellow stain in stored color pictures.
Various techniques are known for preventing the occurrence
of yellow stain in the color image formed on silver halide
color photographic materials. U.S. Patents Nos. 2,788,274
:
.~ .
~1 2'~625
and 3,676,136, Japanese Patent Publications Nos. 32369/73,
20537/74, as well as Japanese Patent Applications (OPI) Nos.
47341/73, 90526/73 and 83441/74 (the symbol OPI as used herein
means an unexamined published Japanese patent application)
5 disclose the use of image stabilizers (or simply stabilizers)
made, individually or in combination, of water-soluble aluminum
salts, water-soluble zinc salts, water-soluble zirconium salts,
sulfurous acid salts, boric acid salts, mono- or di- or poly-
carboxylic acids, water-soluble aldehyde compounds and water-
soluble methylol compounds. Japanese Patent Publications Mos.35240/71 and 20975/74 disclose the treatment with solutions
containing W absorbers. Japanese Patent Publication No.30495/73
discloses the treatment with solutions containing a brightening
agent But these methods are either low in their ef~ectiveness or
accelerate the fading of dye image when they succeed in prevent-
ing yellow stain.
Color photographic materials are processed automatically
and continuously by photofinishers, but with the recent concern
over pollution and wasteful use of water resources, there is a
great demand for saving the use of water in washing step
subsequent to bleaching, fixing or blixing. But if the use of
washing water is simply curtailed, the dye image on a photographic
material that has been processed with a ferric complex salt of
organic acid (which is a typical silver bleaching agent) is
attacked by accelerated yellow stain during extended storage.
As a further disadvantage, a thiosulfate or its silver complex
salt conventionally used as a fixing agent builds up in the
- 2 -
washing water to form silver sul~ide. In addition, the foul
washing water may contaminate the stabilizer which is often
used in the subsequent step. This is another cause of the
formation of silver sulfide and accelerated yellow staining
of the dye image during storage.
SUMMA~Y OF THE INVENTION
Therefore, a general object of the present invention is
to provide an image stabilizer that keeps the processed dye
' image stable over an extended period while inhibiting the
occurrence of yellow stain in the non-image area.
A particular object of the invention is to provide an image
stabilizer that kee~s the dye image stable over an extended
period and inhibits the occurrence of yellow stain in the non-
image area even if a greatly reduced amount of water is ùsed in
the washing step.
Another object of the invention is to provide an image
stabilizer that keeps the dye image stable over an extended
period and inhibits the occurrence of yellow stain in the non-
image area even if the washing step is substantially eliminated
and there is a residuum of the bleaching agent or fixing agent
that has been used to eliminate reduced silver.
Still another object of the inv~ntion is to provide an
image stabilizer that remains stable over an extended period
without forming a precipitate or becoming moldy even when the
silver bleaching agent or fixing agent builds up in the stabilizer.
Yet another object of the invention is to provide an image
stabilizer that can be used not only in processing a c~l~,ùr
4625
photographic material but also a black-and-white photographic
material.
These objects of the present invention are achieved by
an image stabilizer containing a water-soluble bismuth compound.
DETAILED DESCRIPTION OF THE INVENTION
.
The term "image stabilizer" as used herein means a proces-
sing solution used to stabilize a silver halide color photo-
graphic material that has been passed through the steps of color
development, bleaching and fixing. More specifically, the image
stabilizer is used after one of the following dye-image forming
steps, i.e. color development, combined developing and fixing,
and combined developing and blixing. The image stabilizer is
also used after forming a silver image on a black-and-white
photographic material. If it is used in a photographic process
containing no washing step or after a washing step using only
a very samll amount of water, the stabilizer not only stabilizes
the dye image but also washes out chemicals such as developing
agent, bleaching agent or fixing agent that have been deposited
on or introduced into the photographic material before the
stabili~ing step. If treatment with the stabilizer of the
present invention is substituted for the conventional water
washing the stabilizer is replenished in an amount of about
2,500 ml to 25 ml per square meter of the photographic material,
and 1,000 ml to 50 ml, particularly 200 ml to 50 ml, per square
meter of the photographic material is preferred. In this case,
water more than necessary for "rinsing" purpose need not be
used.
The water-soluble bismuth compound contained in the image
-- 4
z~
stabilizer of the present invention dissolves in aqu~ous
solution and may assume any form such as oxides, halides,
nitrates, sulfates, carbonates, hydroxides, or even bismuth
complexes or complex salts with a water-soluble chelating agent.
Examples are bismuth trioxide, bismuth hydroxide, bismuth
pentoxide, metabismuth salt , orthobismuth salt, bismuth
sulfide, bismuth fluoride, bismuth oxyfluoride, bismuth
trifluoride, bismuth pentafluoride, bismuth chloride, bismuth
oxychloride, bismuth trichloride, bismuth dichloride, bismuth
bromide, bismuth oxybromide, bismuth iodide, bismuth oxyiodide,
bismuth hydroiodide, bismuth nitrate, bismuth oxynitrate, bismuth
subnltrate, blsmuth sulfate and bismuth carbonate. These bismuth
compounds may combine with metal ion chelating agents to form
bismuth complexes which are highly soluble in water and are used
with advantage in the present invention. The metal ion chelating
agent here referred to is preferably a water-soluble chelating
agent to be described later which is capable of forming a complex
having a stability constant ~log KMA) of 3 or more with a water-
soluble bismuth ion, said constant being represented by formula
(I):
[MA~
KMA= (I)
~M) ~A~
wherein N is a bismuth ion and A is a complex forming anion.
The complex~s~may be formed by ad~ing bismuth compounds and
chelating agents separately to tha image stabilizer, or
- 5 -
~2~6~5
alternatively, water-soluble bismuth compounds may be reacted
with water-soluble chelating agent to form complexes that are
than added to the image stabilizer.
The water-soluble bismuth compound is preferably used in
an amount of 0.001 to 100 g per liter of the image stabilizer.
More preferably, the bismuth compound is used in an amount of
0.01 to 50g per liter of the image stabilizer, and most
preferably, the compound is used in an amount of 0.01 to 20g.
Among the water-soluble compounds listed above, bismuth
chloride, bismuth nitrate, bismuth sulfate and bismuth acetate
are used with particular advantage, and preferably, they are
pre-mixed with - water-soluble chelating agents to form bismuth
complexes or their salts.
The water-soluble chelating agent that can be used in the
image stabilizer of the present invention preferably forms a
chelate with bismuth ion having a stability constant (.log ~MA)
of 3 or more, more preferably 8 or more, and most preferably
20 or more. The stability constant varies with the conditions
in which the stabilizer is used, such as pH and the amount of
impurities,-and said constant is not the only parameter that
determines an~~ optimum water-soluble chelating agent. Therefore,
any compound that has a stability constant of 3 or more can be
used as the chelating agent, and the higher the water solubility
of the resulting complex and the higher the stability of
. chelate, the better.
-- 6 --
! ~
. ~.,. ' .
. .
6Z5
Illustrative water-soluble chelating agents include
aminopolycarboxylic acids such as diethylenetrimainepenta-
acetic acid, hydroxyethyliminodiacetic acid, diaminopropanol-
tetraacetic acid, and transcyclohexanediaminetetraacetic acid;
aminophosphonic acids such as ethylenediaminetetraquismethylene-
phosphonic acid and nitrilotrimethylenephosphonic acidî organic
phosphonic acids such as l-hydroxyethylidene-l,l-diphosphonic
acid and l,l-diphosphonoethane-2-carboxylic acid; phosphono-
carboXyliC acids such as 2-phosphonobutane-1,2,4-tricarboxylic
10 acid and 1-hydroxy-1-phosphonopropane-1,2,3-tricarboxylic acid;
polycarboxylic acids such as salicylic acid and citric acid;
organic sulfonic acids such as catechol-3,5-disulfonic acid;
and condensed phosphoric acid salts such as sodium pyrophosphate,
sodium tetrapolyphosphate and sodium hexametaphosphate. Di-
ethylenetriaminopentaacetic acid; hydroxyethyliminodiacetic
acid, l-hydroxyethylidene-l,l-diphosphonic acid, condensed
salts thereof, and phosphoric acid salts are preferred.
Particularly preferred are l-hydroxyethylidene-l,l-diphosphonic
acid and their alkali metal salts, ammonium salts and ethanol-
amine salts. Other compounds may also be used if they have achelate stability constant of 3 or more. In a preferred
embodiment, the chelate agents are used in admixture.
The image stabilizer of the present invention may contain
other compounds such as buffers (e.~. borates, metaborates,
borax, phosphates, monocarboxylates, dicarboxylates, polycar-
boxylates, oxycarboxylates, amino acids, primary phosphates,
secondary phosphates, tertiary phosphates, sodium hyrdoxide,
l~ Z5
potassium hydroxide, and ammonia water), surfactants, mold
inhibitors, preservatives and organosulfur compounds.
Compounds such as aldehyde compounds conventionally used to
inhibit yellow stain, as well as brightening agents and UV
absorbers may also be contained in the image stabilizer without
adversely affecting the objects of the present invention.
For the image keeping purpose, the stabilizer of the
present invention is preferably adjusted to pH between 0.1 and
10, more preferably between 2 and 9, most preferably between
3 and 7. The stabilizer is preferably used at between 0 and
60C, more preferably between 20 and 45C. The processing with
the stabilizer is effected in a stabilizer bath or any other
suitable processing tank. The preferred processing tank i5 one
of multi-stage countercurrent type described in S.R. Goldwasser,
"Water Flow Rate in Immersion-Washing of Motion-Picture Film",
Jour SMPT~., 64248-253, May, 1955. 9y using this type of
processing tank, the additional supply of water necessary in
the washing step or that of the image stabilizer of the pr~sent
invention can be further decreased.
The image stabilizer of the present invention can be used
in any step that follows the formation of a dye image by
development. In a preferred embodiment, the stabilizer is used
to process the photographic material that has passed through
the steps of combined developing-blixing, bleaching or blixing.
The two primary purposes of the present invention, i.e. keeping
the image stable over an extended period and inhibiting yellow
-stain, can be achieved most effectively and economically when
~ ZL~Z5
the treatment with the stabilizer immediately follows one of
those image-forming steps without substantial water washingO
The image stabilizer of the present invention proves the most
effective when a ferric complex salt of organic acid is used
as the silver bleaching agent. But it should be understood
that the stabilizer of the present invention can be used in
other embodiments and the results are better than those obtained
by any of the conventional stabilizers.
The ferric complex salt of organic acid that proves the
most effective when it is used as a silver bleaching agent in
combination with the stabilizer of the present invention is
incorporated in a bleaching solution or blix solution to oxidize
the metallic silver (formed as a result of development) to
convert it into silver halide. The complex salt also completes
the action or the coupler. The complex salt is such that amino-
polycarboxylic acid or organic polycarboxylic acid (e.g. oxalic
acid or citric acid) is coordinated with an iron or other metallic
ions. The most preferred organic acid that can be used to form
such ferric complex salt of organic acid is a polycarboxylic
acid of formula (II) or an aminopolycarboxylic acid of formula
(III):
HOCO-Al-Z-A2-COOH (II)
HOCO-A3 / A5-COOH
> N-Z-N \ (III~
Hoco-A4 A6-CH
_ g _
12~4~25
wherein Al~ A2, A3~ A4~ AS and A6 are each a substituted or
unsubstituted hydrocarbon group; and Z is a hydrocarbon group
or /N-A7 (wherein A7 is a hydrocarbon ~roup or a lower aliphatic
carboxylic acid group). These polycarboxylic acids and amino-
polycarboxylic acids may be alkaline metal salts, ammonium
salts or water-soluble amine salts. Typical examples of the
carboxylic acid (II) and the aminopolycarboxylic acid (III)
are listed below.
tl) ethylenediaminetetraacetic acid;
~2) diethylenetriaminepentaacetic acid;
(3) ethylenediamine-N-(~-oxyethyl)-N,N',N'-triacetic acid;
(4) propylenediaminetetraacetic acid;
(5) nitrilotriacetic acid;
(6) cyclohexanediaminetetraacetic acid;
(7) iminodiacetic acid;
(8) dihydroxyethylglycine;
(9) ethylether diaminetetraacetic acid;
(10) glycGlether diaminetetraacetic acid;
(11) ethylenediaminetetrapropionic acid;
(12) phenylenediaminetetraacetic acid;
(13) sodium ethylenediaminetetraacetate;
(14) tetra(trimethylammonium) ethylenediaminetetraacetate;
(15) tetra-sodium ethylenediaminetetraacetate,
(16) penta-sodium diethylenetriaminepentaacetate;
(17) sodium ethylenediamine-N-(~-oxyethyl)-N,N',N'-
triacetate;
(18) sodium propylenediaminetetraacetate;
-- 10 --
L~ 6Z 5
(19) sodium nitrilotriacetate;
(20) sodium cyclohexanediaminetetraacetate;
(21) citric acid;
(22) oxalic acid;
(23) maleic acid;
(24) tartaric acid;
(25) succinic acid;
(26) sulfamic acid;
(27) phthalic acid; and
(28) gluconic acid;
Particularly preferred organic acids include ethylenediamine-
tetraacetic acid, diethylenetriaminepentaacetic acid, and
glycolether diaminetetraacetic acid. The above listed organic
acids, when used in the stabilizer, exhibit high ability to
form a chelate with bismuth ion. They are most preferably
used in combination with phosphonic acid chelatins agents.
In the present invention, silver b]eaching agents or
oxidizing agents other than the ferric complex salt of organic
acid may be used, and persulfates, hydrogen peroxide, iron
chloride and ferric ferricyanine are preferred. It is very
effective for the purposes of the present invention to use a
fixing bath, bleach-fixing bath or combined developing and
blixing bath containing a thiosulfate or thiocyanate as the
main component, but other fixing agents are not excluded.
Suitable fixing agents are those which form a water-soluble
silver complex from bleached silver, and typical examples
include sodium thiosulfate, ammonium thiosulfate, potassium
~2'~ 5
thiosulfate, potassium thiocyanate, ammonium thiocyanate and
sodium thiocyanate.
The washing step may be omitted after treatment with the
stabilizer of the present invention, but if desired, rinsing
with a small amount of water or surface washing in a very short
time may be effected. Such optional washing is effectively
performed by rubbing the processed photographic material with
a wet sponge.
The treatment with the stabilizer of the present invention
is adv~ntageously applied to silver halide photographic materials
such as color paper, reversal color paper, color positive paper,
color negative film, color reversal film and color X-ray film.
The treatment is also applicable to black-and-white photographic
materials. Any soluble si-lYer salt can he recovered from the
stabilizer of the present inVention by suitable methods such as
passing through an ion exchange resin, metal displacement,
electrolysis and silver sulfide precipitation.
The present invention is now described in greater detail
by reference to the following examples which are given here for
illustrative purposes only and are by no means intended to limit
the scope of the invention.
Example l
Samples of SAKURA (trade mark) color paper (product of Konishiroku
Photo Industry Co., ~td.) were subjected to imagewise exposure
; 25 at a reflection density of 1.5. They were subsequently processed
in a usual manner comprising color development, bleach-fixing
and washing, and immersed in 1000 ml of stabilizer formulations
- 12 -
A
.
12'~4625
Nos. 1 to 14 (indicated in Table 1) at 33C for 1 minute. The
stabilized samples were dried and their red reflectlon density
and yellow stain density in the unexposed area were measured.
Thereafter, the samples were subjected to an accelerated
deterioration test for 20 days in a bath held at 60C and 90~
rh. The decrease in the red reflection density and the density
of yellow stain in the unexposed area of each deteriorated
sample were measured. The results are shown in Table 2.
- 13 -
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:~4~625
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O I I I I ~1 ~ O ~ ~ 0 3
CS~ . I I I ~ ' I ~ ~ N ,.
OD I I I ~- ~N I ~ ~ X
i_ I I I I I I O I N ~ ,q
~ ~D _l I I I I I ~r .Y
i~ 1~ .. ___ . _ N ~1 K
~ I I I I t~l I I I ~ ~ rl
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- 14 -
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.~ ~
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~ ~ ~ c~ r a~
O ~ h ~ ~ ~ ~ ~ ~1 ~1 ~1 ~1 ~1 ~1 ~1 ~1 ~1
: h o o o o o o o o o o o o o o
; ~--.''
. ~ ', '~
. ~ ~ ~
~i ' U~ 9 U~
. 3 ~ o o o o c~ o o o o o o o o o
' O 1: ' O' O O' O o O o O o o o O O 'o .
. ~ ~{ . .
N ¦ ---- I .
~ : h .
:E~ 1~, .
: ~ ~ ~ r~ u~
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:' ~:
.~
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h . _1 ~1 ~1 ~1 ~1
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(d U~ rl ~3-rl
O ~ h~
d~1 ~
8~ ~.~
-- 15 --
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As is clear from Table 2, control stabilizers Nos. 2, 4
and 5 was no more effective than sample No.1 (acidic water
only) in inhibiting yellow stain. Sample No.4 was somewhat
effective but then, the photographic material processed with
it experienced a significant drop in red reflection density.
Stabilizers Nos. 6 to 14 according to the present invention
were very effective in inhibiting yellow stain and the drop
in the red reflection density was very small. As a result,
the dye image and unexposed area of the photographic materials
treated with these samples remained very stab]e.
Example 2
A roll of Sakura color paper was printed in an imagewise
pattern and subjected to continuous processing (running proces-
sing) in an automatic developer of endless belt type according
to Schemes Nos. 1 and 2 specified below. The processing steps
and the formulations of the processing solutions employed therein
are identified below.
Processing steps
1. C~lor development 33C, 3 min. 30 sec.
2. Bleach-fixing 33C, 1 min. 30 sec.
3. Stabilization 25-30C, 3 min.
4. Dryina 75-80C, ca. 2 min.
; Loquor in color developing tank
Benzyl alcohol 15 ml
~thylene glycol 15 ml
Potassium sulfite 2.0 g
Potassium bromide 0.7 g
, .
12~4~i~5
Sodium chloride Q,2 g
Potassium carbonate 30.0 g
Hydroxylamine sulfate 3.0 g
l-Hydroxyethylidene-l,l-diphosphonic acid 1.0 g
Magnesium chloride hexahydrate 0.5 g
Hydroxyethyliminodiacetic acid 3,0 g
3-Methyl-4-amino-N-ethyl-N-(~-methanesulfon-
amidoethyl)-aniline sulfate 5.5 g
Brightener ~4,4'-diaminostilbenedisulfonic
acid derivative) 1.0 g
Potassium hydroxide 2.0 g
Water to make 1,000 ml
Replenisher for color development tank
Benzyl alcohol 20 ml
Ethylene glycol 20 ml
Potassium sulfite 3.0 g
Potassium carbonate 3~.0 g
Hydroxylamine sulfate 4.0 g
l-~ydroxvethylidene-l,l-diphosphonic acid 2.0 g
Magnesium chloride hexahydrate ~.8 g
Hydroxyethyliminodiacetic acid 3.5 g
3-Methyl-4-amino-N-ethyl-N-(~-methanesulfon-
amidoethyl)-aniline sulfate 7.0 g
Brightener (4,4'-diaminostilbenedisulfonic
acid derivative 1.5 g
Potassium hydroxide 3.0 g
Water to make 1,000 ml
Liquor in bleach-fixing tank
Ethylenediaminetetraacetate acid ferric
ammonium dihydrate 60 g
- 17 -
~ Z~25
Ethylenediaminetetraacetic acid 3 g
Ammonium thiosulfate (70% solution) 100 ml
Ammonium sulfite (40~ solution) 27.5 ml
Water to make 1,000 ml
pH adjusted at 7.1 with potassium carbonate
or glacial acetic acid
Replenisher A for bleach-fixing tank
Ethylenediaminetetraacetate ferric ammonium
dihydrate 260 g
Potassium carbonate 42 g
Water to make 1,000 ml
pH adjusted at 6.7 + 0.1
Replenisher B for bleach-fixing tank
Ammonium thiosulfate (70~ solution) 50Q ml
Ammonium sulfite (40% solution) 250 ml
Ethylenediaminetetraacetic acid 17 g
Glacial acetic acid 85 ml
Water to make 1,000 ml
pH adjusted at 4.6 + 0.1
The automatic developer was charged with the color develop-
ment liquor, bleach-fixing liquor and one of the stabilizer
formulations indicated below. Color paper samples were
subjected to a running test by supplying the color development
replenisher, bleach-fixing replenishers A and B and stabilizer
replenisher (to be identified below) through a metering cup at
3-minute intervals. The development replenisher was supplied
in an amount of 324 ml, and blix replenishers A and B were
each supplied in an amount of 25 ml per square meter of the
- 18 -
~z~ Z~
color paper. The stabilizing tank was of countercurrent type
that consisted of first, second and third compartments in the
order of the supply of the color paper. The stabilizer was
first fed to the third compartment, the overflow being fed to
the second compartment, and the overflow from the second
compartment was directed to the first compartment, and the
overflow from the first chamber was discharged out of the
machine.
The running processing according to Scheme No.l was
regarded as being stationary when the total amount of the blix
replsnisher (replenishers A and B plus the color developer
carried by the photographic material into the blixing tank)
became twice the tank capacity.
Scheme No _
In one control experiment, an aqueous solution (formulation
No.1 in Table 3) containing 2g of glacial acetic acid per liter
and which was adjusted to pH 4.2 with sodium hydroxide was
passed through the stabilizer tank in an amount of 200 ml per
square meter of color pepr. When the stabilizer composition and
the carrvover from the blixing solution was found to have become
stable by sampling the liquor in each compartment of the stabi-
lizer tank, various compounds were added to the liquor in each
compartment according to formulations Nos. 2 to 9 noted in
Table 3, and each liquor wa~ adjusted to a pH of 4.2 with aqueous
sodium hydroxide.
Sakura color paper samples that had been subjected to
imagewise exposure at a reflection density of 1.5 were processed
- 19 -
~,
. .
.. .
~2'~6~5
according to the above scheme, and their red reflection density
and yellow stain density in the unexposed area were measured.
Thereafter, the samples were subjected to an accelerated
deterioration test for 10 days in a bath held at 60C and 80%
rh. The decrease in the red reflection density and the density
of yellow stain in the unexposed area of each deteriorated
sample were measured. The results are shown in Table 4. Table
4 also lists the date of a photographic material that was not
stabilized but washed with a large quantity of water as in the
conventional manner.
Scheme No.2
After the running processing in Scheme No.l, samples were
taken from the liquor in the third compartment of the stabilizing
tank and transferred to conical flasks (500 ml capacity) which
were left to stand for 40 days during which the samples were
checked for the formation of a precipitate. The results are
noted in Table 5.
.
- 20 -
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- 21 -
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-- 22 --
-- .
625
Table 5
Change with..time
. . . Formulation days passed
No. 10 20 30 . 40
-
. 1 _ + ~+ ~
. 2 _ + +~ ~+
3 ++ ~+ ~ ++
Comparative 4 ++ ++ ++ ++
samples .
10 . 5 _ ~ ~+ +~
6 ~+ ~ +~ ~+
~Sensitizers of the 7 _ _ _ _ .
¦present invention 9 . _ _ _ _
- : transparent, no precipitate
+ : some precipitate, a bit cloudy
+~: much precipitate, cloudy throughout
As Table 4 shows, the sample that was directly stabilized
with formulation No.l (simply p~-adjusted with acetic acid)
without washing had a bit more yellow stain and faded more than
the sample that was not stabilized and simply washed with water. In
an experiment using a stabilizer that was not pH-adjusted, the
degree of yellow stain was more than 0.3. Stabilizer formulations
: Nos. 2 to 7 were the same as those which were conventionally
used to inhibit yellow stain and they consisted of citric acid
(polycarboxylic acid) either alone or in combination with potassium
` aluminum sulfate 24 hydrate (water-soluble aluminum salt), zinc
- 23 -
12'~;ZS
sulfate (water-soluble zincic acid) or ~irconium sulat~.
(water-soluble zirconium salt). They could only slightly
inhibit the occurrence of yellow stain. Formulations Nos. 4
and 6 that also contained formaldehyde (aldehyde compound)
were particularly unsuitable for practical use since they
accelerated the decrease in the density of cyan dye.
Formulations Nos. 8 and 9 according to the present invention
were very effective in inhibiting yellow stain without decreasing
the density of cyan dye. As is clear from Table 5, the stabili-
zers of the present invention were entirely free from precipitateduring extended storage. They were also free from putrefaction,
mold or bacterial growth. Therefore, they were very effective
not only in eliminating the washing step or reducing the amount
of water to be used in the washing step but also in decreasing
the additional supply of stabilizer replenisher.
Example 3
Samples of black and white photographic film YOSHINO ~S
(trade mark; product of Konishiroku Photo Industry Co., Ltd.)
were developed with KONITONE (trade mark for a developing agent
of Konishiroku Photo Industry Co., Ltd.), fixed with RONI-FIX
(trade mark for a fixing agent of the same company), washed under
flushing water for 2 minutes, immersed in 5 stabilizers of the
formulations listed in Table 6 for one minute at 20 C, and
dried.
- 24 -
, ~
;25
__ _ _
In O ~ ~ O
o~
o h ~::
o~ N
~ :~ ~
,~o
,.. a
o
I .~ S~
o ~
,~ ~ r 8
~D .~
_~ O rl O In
E~ O Il~ ~0~ 3
Z O ~I.Y
O ~ ~U~ .
d O n~ o
~ d O
~ F. - $3 _
~ O ~d 3 a
g hal ~ $ ~ O
G ~ ~ $ U
~
--~
m-u
~2~625
The processed samples were subjected to an accelerated
deterioration test for 40 days at 60C and 80~ rh. under
illumination of 200 lux. Compared with the samples stabilized
with control formulations Nos. 1 and 2, those which were
stabilized with formulations Nos. 3 to 5 had very low minimum
white densities ~stain) in the unexposed area. The samples
stabilized with the control formulations turned brown in the
silver image area, but brownin~ taking place in those stabilized
with the formulations of the present invention was negligible.
These differences increased when the samples were directly
stabilized without washing with water. The increase in the
hellow stain in the unexposed area and the brswning of the silver
image area were accelerated in the samples stabilized with the
control formulations without washing with water, but the samples
lS stabilized with the formulations of the present invention were
effectively protected against increasing stain in the unexposed
area and browning in the silver image area even when no washing
was conducted. This data shows that the stabilizer of the
present invention is also effective for black-and-white photo-
graphic materials.
- 26 -
