Note: Descriptions are shown in the official language in which they were submitted.
MULTI-PART BLEACH-FIX REPLENISHER AND USE THEREOF IN
PHOTOG~APHIC PROCESSING .,
` Background of the Invention
This invention relates to the processing of
silver halide photographic materials. More
specifically, it relates to a method of and composition
for replenishing a bleach-fix solution.
Silver halide light-sensitive materials in
which the primary silver halide species is silver
chloride are generally processed by color developing
and bleach-fixing the material. The bleach-fix
solution generally contains a ferric complex salt of an
organic chelating compound such as
ethylenediaminetetraacetic acid (EDTA) and a fixing
agent such as thiosulfate.
As environmental issues become increasingly
important, it is desirable to eliminate unwanted
chemicals such as ammonia and ammonium salts from
photographic processing solutions. In the processing
sequence noted previously, the bleach-fix is
; replenished at a low rate in an effort to minimize the
effluent being discharged to the sewer. Currently, all
bleach-fix solutions having a replenishment rate of
53.8 ml/m2 or less use ammonium thiosulfate as the
fixing agent. Ef~orts to ~emove or reduce the ammonia
by substituting a different univalent cation while
~ maintaining a low replenishment rate have always failed
i due to the low solubility of non-ammonium systems that
contain a ferric salt of an organic chelating agent and
~ a fixing agent.
; U.S. Patent 4,954,426 discusses a low
replenishment rate bleach-fix solution with not less
than 80 mole % of the total non-metallic cations
present in the replenisher for the bleach-fix solution
:~ being ammonium ions. U.S. Patent 3,706,561 describes a
low ammonia bleach-fix having a higher pH to circumvent
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solubility problems. The use of a higher pH retards
bleaching and the use of a secondary ligand is
therefore required.
Until recently, bleach-fix replenishers have
S been one-part solutions. KODAK EKTACOLOR RA Bleach-Fix
D-Rep, which has an effective replenishment rate of
19.4 ml/m2, is a three-part replenisher. This system,
however, uses ammonium thiosulfate as the fixing
component. Japanese Kokai SHO 55(1980)-79446 discusses
l0 the use of a two-part replenishment system to achieve a
low replenishment rate. With this system, a 90 second
bleach-fix is used and the pH of the bleach-fix is
always maintained above 6.5. Japanese Kokai SHO
55(1980)-77743 also discusses a two-part replenishment
15 system. The pH of the bleach-fix of this system is
always maintained above 7.0, which results in poorer
bleaching as discussed previously.
U.S. Patent 5,055,382 describes a three-part
bleach regeneration kit, however, the first part is an r
20 alkaline solution containing a bu:Efering agent and an
aminopolycarboxylic acid which is added to the spent
bleach-fix solution before electrolytic recovery of the
silver therefrom. The other two parts contain,
respectively, an iron salt and a thiosulfate, and are
25 also added to the spent bleach-fix solution.
The problem to be solved with this invention
is to provide a replenisher for a bleach-fix solution
which has a low or no ammonium ion content and which
can be replenished at a very low rate. The replenisher
30 must be able to maintain a bleach-fix bath which can
rapidly bleach-fix a photographic element and which has
a pH under 6.5 to maintain adequate bleaching ability.
., .
Summary of the Invention
3s This invention provides a replenisher for a
- bleach-fix solution, said replenisher comprising
discrete and separate parts A, B, and C, wherein part A
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contains thiosulphate and a preservative; part B
contains a ferric aminopolycarboxylic acid complex; and
part C contains an acid, and the total ammonium ion
content of parts A and B is less than 50 mole % of the
total cations. In one embodiment, the thiosulphate
consists of sodium or potassium thiosulphate and the
ferric aminopolycarboxylic acid complex consists of a
ferric sodium or ferric potassium aminopolycarboxylic
acid complex.
This invention further provides a method of
replenishing a bleach-fix solution comprising adding to
the bleach-fix solution a replenisher as described
above, while maintaining the pH of the bleach-fix
solution between 5.5 and 6.5. It also provides a
lS method of bleaching and fixing a photographic element
comprising processing the photographic element in a
bleach-fix solution for 45 seconds or less, wherein the
bleach-fix solution is replenished with a replenisher
as described above; and wherein the pH of the bleach-
fix solution is maintained between 5.5 and 6.5. In oneembodiment of this method, the photographic element has
a silver chloride content of greater than 90 mole % and
a silver content of less than 0.86 g/m2.
The three-part replenishment system of this
invention provides a replenisher in which low ammonia
or non ammonium constituents are stable at high
concentrations. Ammonium thiosulfate can be replaced
either entirely or in part by sodium or potassium
thiosulfate in a bleach-fix formulation. Ferric
ammonium aminopolycarboxylic acids can also be replaced
with potassium or sodium aminopolycarboxylic acids if
so desired. This allows for the removal or reduction
of ammonia in a bleach-fix solution while maintaining a
replenishment rate less than 27 ml/m2. It also allows
for the formulation of a bleach-fix solution which
operates at a pH less than 6.5 and requires a
processing time no greater than 45 seconds.
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Detailed Description
The replenisher of this invention comprises
three separate and discrete parts. Part A contains a
5 thiosulfate and a preservative, Part s contains a
ferric aminopolycarboxylic acid, and Part C contains an
acid. The thiosulfate can be an alkali metal
thiosulfate, with sodium or potassium thiosulphate
being preferred. It can also be a combination of an
alkali metal thiosulphate with ammonium thiosulphate.
If ammonium thiosulphate is used, the mole % of
ammonium cations contained in Parts A and B must be
less than sa mole % of the total cations present, and
preferably less than 20 mole %. Preferably, the
IS thiosulphate does not contain any ammonium ion.
The concentration of thiosulphate should be
about .75 mol/l to about 5.0 mol/l, with 2.0 mol/l to
3.0 mol/l being preferred. Part A should also contain
a preservative. The preferred preservative is sulfite,
some examples of which are sodium sulfite, sodium
metabisulfite, potassium sulfite, lithium sulEite,
ammonium sulfite, sodium bisulfite, ammonium bisulfite,
potassium metabisulfite, and sodium formaldehyde
bisulfite. The amount of the preservative may be from
~ 25 .05 mol/l to 1.0 mol/l, with .45 mol/l to .55 mol/l
; being preferred. A mixture of preservatives may be
also be used. Part A may also contain other additives
such as, among others, bleach accelerators, fix
accelerators, free ligand, and buffering agents. The
pH of Part A may be 4 to 10.
The aminopolycarboxylic acid of the ferric
aminopolycarboxylic acid complex in Part B can be any
such acid which is useful in bleaching silver halide
emulsions. Examples of useful aminopolycarboxylic
acids include, but ar~ not limited to, the following:
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A- 1: Diethylenetriaminepentaacetic acid
A- 2: Pentasodium diethylenetriaminepentaacetate
A- 3: Ethylenediamine-N-(2,hydroxyethyl)-N,N',N'-
triacetic acid
A- 4: Trisodium ethylenediamine-N-(2,hydroxyethyl)-
N,N',N'-triacetate
A- 5: Triammonium ethylenediamine-N-(2,hydroxyethyl)-
N,N',N'-triacetate
A- 6: 1,2-Diaminopropanetetraacetic acid
A- 7: Disodium 1,2-diaminopropanetetraacetate
A- 8: Nitrilotriacetic acid
A- 9: Sodium nitrilotriacetate
A- 10: Cyclohexanediaminetetraacetic acid
A- 11: Disodium cyclohexanediaminetetraacetate
A- 12: N-Methyliminodiacetic acid
. A- 13: Iminodiacetic acid
A- 14: Dihydroxyethyl glycine
A- 15: Ethylene bis(oxyethylnitrilo)tetraacetic acid
A- 16: Ethylenediaminetetrapropionic acid
A- 17: 1,3 Diaminepropanetetraacetic acid
A- 18: Ethylenediaminetetraacetic acid
A- 19: 1,2-Propylenediaminetetraacetic acid, or
alkaline metal salts or an~monium salts thereof
A- 20: Triethylenetetraminehexaac~etic acid, or alkaline .
salts or ammonium salts thereof
A- 21: 1,4-Diaminobutanetetraacetic acid or alkaline
salts or ammonium salts thereof
A- 22: 2-Propanoldiaminetetraacetic acid or alkaline
salts or ammonium salts thereof
A- 23: 1,3-Butylenediaminetetraacetic acid or alkaline
salts or ammonium salts thereof
:. .
The preferred aminopolycarboxylic acid is
ethylenediaminetetraacetic acid (EDTA).
The ferric aminopolycarboxylic acid complex
can be a ferric ammonium aminopolycarboxylic acid
complex or a complex with an alkali metal such as
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sodium or potassiu,m. It may also be a mixture of the
above. A non-ammonium complex is preferred for
environmental reasons. The concentration of the ferric
aminopolycarboxylic acid complex should be from about
S .05 mol/l to about 2.0 mol/l, with 1.25 mol/l to 1.75
mol/l being preferred. Part B can also contain various
additives such as excessive ligand and buffers. The pH
of this solution may be 3 to 10.
The third component, Part C, is an acid. The
acid must be one which is suitable for use in
photographic processing solutions. The pH of Part C
should be such that the pH of the bleach-fix solution
is maintained at a pH of 5.5 to 6.5 while maintaining a
low replenishment rate. Examples of suitable acids are
- 15 acetic, propionic, citric, or succinic, sulfonic, and
nitric acid. Acetic acid is preferred. It is this
separate acid component which allows for the low
replenishment rate of this replenisher. Because the
other parts are not required to have a low pH, the
concentration of the thiosulphate and the ferric
aminopolycarboxylic acid complex can be higher without ~ ;
` losing solubility.
Each part of the replenisher should be added
directly to the bleach-fix solution with no pre-mixing
2s or dilution. One of the obj~cts of this invention is
to provide a replenisher having the lowest possible
replenishment rate while still maintaining a stable and
effective bleach-fix solution and replenisher. The
total amount of the replenisher which must be added to
the bleach-fix solution is dependent on the type of
`~ cation in Parts A and B and on the amount of carryover
i from the preceding solution. Carryover is the amount
of liquid per square unit which is carried by the
photographic element from the preceding bath into the
bleach-fix solution. The preceding bath may be any one
of several different baths, such as a developer bath, a
stop bath, or a wash bath. The invention herein is
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most useful in the situation where the preceding bath
is alkaline.
When using an alkali metal thiosulfate with a
ferric ammonium polycarboxylic acid complex, the amount
- 5 of replenisher used per square unit of photographic
material processed is about 0.5 to 1 times the
carryover from the preceding solution. For example, if
the carryover is 43 ml/m2, then 21.5 to 43 mls of
replenisher should be added for each square meter of
the photographic element which is processed. Of the
total amount of replenisher added, the preferred ratio
of Part A/Part B/Part C is approximately 3/1/1.
When using an alkali metal thiosulfate with a
ferric potassium polycarboxylic acid complex, the
amount of replenisher used per square unit of
photographic material processed is about 0.625 to 1.25
times the carryover from the preceding solution.
Therefore, if the carryover is 43 ml/m2, then about
26.9 to 53.8 mls of replenisher should be added for
each square meter of film which is processed. Of the
total amount of replenisher added, the preferred ratio
of Part A/PartB/PartC is approximately 3/1/1.
When using an alkali metal thiosulfate with a
ferric sodium polycarboxylic acid complex, the amount
of replenisher used per square unit of photographic
material processed is about 2.5 to 5 times the
carryover from the preceding solution. Therefore, if
the carryover is 43 ml/m2, then 107.5 to 215 mls of
replenisher should be added for each square meter of
film which is processed. Of the total amount of
replenisher added, the preferred ratio of Part A/Part
B/Part C is approximately 3/6/1.
As the level of ammonium cation is increased
in each part, the quantity of solution used in that
part of the replenisher will decrease. Using the above
guidelines, those skilled in the art will be able to
determine the optimal level of replenisher which may be
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utilized for vario~s replenisher formulations.
sy utilizing the replenishers of this
invention, the bleach-fix solution to be replenished
can be maintained at a pH between 5.5 and 6.5, and the
working strength of the bleach-~ix solution can be
maintained as follows: .05 mol/l to 1.0 mol/l
thiosulfate, .01 mol/l to 0.5 mol/l preservative, and
.025 mol/l to .25 mol/l ferric aminopolycarboxylic acid
complex; with 0.4 mol/l to 0.65 mol/l thiosulfate;
0.075 mol/l to 0.2 mol/l preservative; and 0.025 mol/l
to 0.2 mol/l ferric aminopolycarboxylic acid complex
being preferred. This allows for a bleach-fix time of
45 seconds or less.
The photographic elements to be processed can
IS contain any of the conventional silver halides as the
photosensitive material, for example, silver chloride,
silver bromide, silver bromoiodide, silver
chlorobromide, silver chloroiodide, and mixtures
thereof. Preferably, however, the photographic element
is a high chloride element, containing at least 90 mole
% silver chloride. The photographic elements most
useful with this invention have a silver content of
less than .86 g/m2.
The photographic elements can be single color
elements or multicolor elements. Multicolor elements
typically contain dye image-forming units sensitive to
each of the three primary regions of the visible
spectrum. Each unit can be comprised of a single
emulsion layer or of multiple emulsion layers sensitive
to a given region of the spectrum. The layers of the
element, including the layers o~ the image-forming
units, can be arranged in various orders as known in
the art. In an alternative format, the emulsions
sensitive to each of the three primary regions of the
spectrum can be disposed as a single segmented layer,
e.g., as by the use of microv~ssels as described in
Whitmore, U.S. Patent 4,362,806, issued December 7,
.
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1982. The element,can contain additional layers such
as filter layers, interlayers, overcoat layers, subbing
layers, and the like.
In the following discussion of suitable
s materials for use in the emulsions and elements of this
invention, reference will be made to Research
Disclosure, December 1989, Item 308119, published by
Kenneth Mason Publications, Ltd., Dudley Annex, 12a
North Street, Emsworth, Hampshire P010 7DQ, ENGLAND,
the disclosures of which are incorporated herein by
reference. This publication will be identified
hereafter by the term "Research Disclosure".
The silver halide emulsions employed in the
elements of this invention can be either negative- -
lS working or positive-working. Examples of suitable
emulsions and their preparation are described in
Research Disclosure Sections I and II and the
publications cited therein. Some of the suitable
vehicles for the emulsion layers and other layers of
elements of this invention are described in Research
Disclosure Section IX and the publications cited
therein.
The silver halide emulsions can be chemically
and spectrally sensitized in a variety of ways,
examples of which are described in Sections III and IV
of the Research Disclosure. The elements of the
invention can include various couplers including, but
not limited to, those described in Research Disclosure
Section VII, paragraphs D, E, F, and G and the
publications cited therein. These couplers can be
incorporated in the elements and emulsions as described
in Research Disclosure Section VII, paragraph C and the
publications cited therein.
The photographic elements of this invention
or individual layers thereof can contain among other
things brighteners (examples in Research Disclosure
Section V), antifoggants and stabilizers (examples in
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Research Disclosure Section VI), antistain agents and
image dye stabilizers (examples in Research Disclosure
Section VII, paragraphs I and J), light absorbing and
scattering materials (examples in Research Disclosure
S Section VIII), hardeners (examples in Research
Disclosure Section X), plasticizers and lubricants
(examples in Research Disclosure Section XII),
antistatic agents (examples in Research Disclosure
- Section XIII), matting agents (examples in Research
Disclosure Section XVI) and development modifiers
(examples in Research Disclosure Section XXI).
The photographic elements can be coated on a
; variety of supports including, but not limited to,
those described in Research Disclosure Section XVII and
the references described therein.
Photographic elements can be exposed to
actinic radiation, typically in the visible region of
the spectrum, to form a latent image as described in
Research Disclosure Section XVIII and then processed to
form a visible dye image, examples of which are
described in Research Disclosure Section XIX.
Processing to form a visible dye image includes the
; step of contacting the element with a color developing
agent to reduce developable silver halide and oxidize
the color developing agent. Oxidized color developing
agent in turn reacts with the coupler to yield a dye.
~ he color developing solutions typically
contain a primary aromatic amino color developing
agent. These color developing agents are well known
and widely used in variety of color photographic
processes. They include aminophenols and p-
phenylenediamines.
Examples of aminophenol developing agents
include o-aminophenol, p-aminophenol, 5-amino-2-
hydroxytoluene, 2-amino-3-hydroxytoluene, 2-hydroxy-3-
amino-l,4-dimethylbenzene, and the like.
Particularly useful primary aromatic amino
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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-phenylenediaminemonohydrochloride, 4-N,N-
diethyl-2-methylphenylenediaminemonohydrochloride, 4-
(N-ethyl-N-2-methanesul~onylaminoethyl)-2-
methylphenylenediamine sesquisulfate monohydrate, 4-(N-
- 10 ethyl-N-2-hydroxyethyl)-2-methylphenylenediamine
sulfate, 4-N, N-diethyl-2, 2'-
methanesulfonylaminoethylphenylenediamine
hydrochloride, and the like.
In addition to the primary aromatic amino
color developing agent, color developing solutions
typically contain a variety of other agents such as
alkalies to control pH, bromides, iodides, benzyl
alcohol, anti-oxidants, anti-foggants, solubilizing
agents, brightening agents, and so forth.
Photographic color developing compositions
are employed in the form of aqueous alkaline working
solutions having a pH of above 7 and most typically in
the range of from about 9 to about 13. To provide the
necessary pH, they contain one or more of the well
known and widely used pH buffering agents, such as the
alkali metal carbonates or phosphates. Potassium
carbonate is especially useful as a pH buffering agent
for color developing compositions.
With negative working silver halide, the
processing step described above gives a negative image.
To obtain a positive (or reversal) image, this step can
be preceded by development with a non-chromogenic
developing agent to develop exposed silver halide, but
not form dye, and then uniformly fogging the element to
render unexposed silver halide developable.
Alternatively, a direct positive emulsion can be
employed to obtain a positive image.
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Development is followed by the conventional
steps of bleach-fixing to remove silver and silver
halide, washing and drying.
Typically, a separate pH lowering solution,
referred to as a stop bath, is employed to terminate
development prior to bleaching. A stabilizer ~ath is
commonly employed for final washing and hardening of
the bleached and fixed photographic element prior to
drying. Conventional techni~ues for processing are
illustrated by Research Disclosure, Paragraph XIX.
Preferred processing sequences for color
photographic elements, particularly color negative
films and color p~int papers, include the following:
(P-l) Color development / Stop / Bleaching-fixing
/ ~ashing / Stabilizing / Drying.
(P-2) Color development / Stop / Bleaching-fixing
/ Stabilizing / Drying.
~P-3) Color development / Bleaching-fixing / r
Washing / Stabilizing / Drying.
(P-4) Color development / sleaching-fixing /
Washing.
(P-5) Color development / Bleaching-fixing /
Stabilizing / Drying.
(P-6) Color development / Stop / Washing /
Bleaching-fixing / Washing / Drying.
In each of processes (P-l) to (P-6),
variations are contemplated. For example, a bath can
be employed prior to color development, such as a
' prehardening bath, or the washing step may follow the
stabilizing step. Additionally, reversal processes
which have the additional steps of black and white
development, chemical fogging bath, light re exposure,
and washing before the color development are
contemplated.
The following examples are intended to
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illustrate, withou,t limiting, this invention.
Exam~le 1
s A bleach-fix tank tBleach-Fix 2) was prepared
that simulates the tank that would be formed if the
following replenisher solutions were used at the
indicated rates:
Replenisher Part A - Sodium Thiosulfate (2.75
M), Potassium Sulfite (0.48 M), solution replenished at
12.9 ml/m2
Replenisher Part B - Ferric Ammonium EDTA
(1.56 M), replenished at 4.3 ml/m2
Replenisher Part C - Acetic Acid (8.5 M),
replenished at 4.3 ml/m2 r
A carryover of 43 ml/m2 is assumed for all of
these calculations.
A si.mulated seasoned bleach-fix solution
containing ammonium thiosulfate (Bleach-Fix 1) was also
2~ prepared.
TABLE 1
Bleach-Fix Tank 1 ~leach-Fi~ Tank 2
Ammonium Thiosulfate 0.55M Sodium Thiosulfate 0.55M
Potassium Sulfite O.lM Potassium Sulfite O.lM
: Ferric Ammonium EDTA O.lM Ferric Ammonium EDTA O.lM
EKTACOLOR EDGE~ paper was processed using
Kodak Process RA-4 in which the processing times and
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steps are as follows:
Developer 45 Seconds 95F
Bleach-Fix (Bleach- 45 Seconds 95F
Fix 1 or Bleach-Fix 2)
Wash 90 Seconds 95F
The silver remaining in the paper was
5 determined by measuring the IR density of both the D-
Min and D-Max of the paper and calculating the
difference. This resulting difference was used as the
measurement for retained silver. A fully bleached
sample would be expected to have a difference of 0.06
or less. The retained silver left in the paper is
given ln Table II.
TABLE II
, ' ,:
15Silver (IR DMax - D~in) R~mai~ing I~ Pa~er After
Proce~ing
: Bleach-Fix Bath S =
1 (Comparative) 0.06
2 (Invention) 0.06
The results show that the paper was
desilvered satisfactorily by both the bleach-fix
~ solution using sodium thiosulfate as the fixing agent
`' and by the solution using ammonium thiosulfate as the
fixing agent.
As a follow-up to this experiment, the
following bleach-fix solutions were prepared:
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TABLE III
One Part Bleach-Fix Replenisher 3 Bleach-Fix Tank 4
Sodium Thiosulfate 0.99M Sodium Thiosulfate 0.55M
Potassium Sulfite 0.18M Potassium Sulfite 0.lMFerric Ammonium EDTA 0.18M Ferric Ammonium EDTA 0.lM
p~ (adj. w/K2C03) 4.8 pH (adj. w/K2C03) 6.1 ..
Bleach-Fix Replenisher 3 represents the one-
part replenisher solution that would be necessary toyield Bleach-Fix Tank 4 (which is identical to Bleach-
Fix Tank 2 used in Table I) assuming a replenishment
rate of 53.8 ml/m2 and a carryover of 43 ml/m2. Both
solutions 3 and 4 were stored at room temperature for 8
weeks. A precipitate (Ferric Sodium FDTA) was observed
in Bleach-Fix Replenisher 3 but not in Bleach-Fix Tank
4. These results demonstrate that a one part bleach-
fix replenisher such as Bleach-Fix Replenisher 3 cannot
be used to replenish Bleach-Fix Tank 4 due to the
instability of the replenisher so:lution. The present
invention circumvents this problem.
Exam~le 2
The following replenisher solutions at the
indicated rates could also be used:
Replenisher Part A - Potassium Thiosulfate
(2.75 M), Potassium Sulfite (0.48 M), solution
replenished at 12.9 ml/mt2
Replenisher Part B - Ferric Ammonium EDTA
(1.56 M), replenished at 4.3 ml/m2
Replenisher Part C - Acetic Acid (8.5 M),
replenished at 4.3 ml/m2
2 l o ~
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A carryover of 43 ml/m2 is assumed for all of
these calculations.
Exam~le 3
The following replenisher solutions at the
indicated rates could also be used:
Replenisher Part A - Sodium Thiosulfate (2.4
M) or Potassium Thiosulfate (2.4 M), Potassium Sulfite
(0.44 M), solution r~plenished at 16.1 ml/m2
Replenisher Part s - Ferric Potassium EDTA
15 (1.3 M), replenished at 5.4 ml/m2
:` :
Replenisher Part C - Acetic Acid (7.3 M),
replenished at 5.4 ml/m2
; 20 A carryover of 43 ml/m2 is assumed for all of
these calculations.
Exam~le 4
2s The following replenisher solutions at the
indicated rates could also be used:
.' ' .
Replenisher Part A - Sodium Thiosulfate (2.7
; M) or Potassium Thiosulfate (2.7 M), Potassium Sulfite
(0.44 M), solution replenished at 32.3 ml/m2
Replenisher Part B - Ferric Sodium EDTA
(0.245 M), replenished at 64.6 ml/m2 ~-
3s Replenisher Part C - Acetic Acid (7.5 M),
replenished at 10.8 ml/m2
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A carryover of 43 ml/m2 is assumed for all of
these calculations.
.:
Exam~le 5
S
-~ The following simulated bleach-fix tanks were
prepared:
. TABLE IV
Bleach-Fix Tank 5 Bleach-Fix Tank 6
. Ammonium Thiosulfate 0.57M Sodium Thiosulfate 0.57M
: Sodium Sulfite 0.14M Sodium Sulfite 0.14M
Ferric Ammonium EDTA 0.15M Ferric Ammonium EDTA 0.15M
Mercapto Triazole 0.003M Mercapto Triazole 0.003M
. pH (adj._w/K2CO3) 6.5 _ pH ~adj. w/K2CO3) 6.5
'
EKTACHROME Radiance paper was processed using
Kodak Process R-3 in which the processing times and
steps are as follows:
First Developer 75 Seconds 38C
First Wash 90 Seconds 35 - 41C
Reexposure With 5 to 10 Seconds
Fluorescent Light
Color Developer 135 Seconds 38C
Second Wash 45 Seconds 25 - 41C
Bleach-FiX (Bleach-FiX 120 Seconds 38C
- 5 or Bleach-Fix 6)
Final Wash 135 Seconds 25 - 41C
Dry As Needed At Less Than 71C
''
The silver remaining in the paper was
determined by measuring the IR density of both the D-
Min and D-Max of the paper and calculating the
difference. This resulting difference is used as the
measurement for retained silver. A fully bleached
sample would be expected to have a difference of 0.06
,'
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-18-
or less. The retained silver left in the paper is
given in Table V.
TABLE V
S
Sil~er (IR DMax - D~in) Remainin~ a~er Aftar
Processing
5 (Comparative) 0.06
. . .
The results show that the paper is desilvered
satisfactorily by both the bleach-fix solution using : -
sodium thiosulfate as the fixing agent and by the
solution using ammonium thiosulfate as the fixing
agent.
As a follow-up to this experiment, the
following bleach-fix solutions were prepared:
TABLE VI ! I
. . , . ~
: One-Pa~t Bleach-Fix Re~lenisher 7 Bleach-Fix Tank 8.
~ Sodium Thiosulfate 0.65M Sodium Thiosulfate 0.57M
: Sodium Sulfite 0.16M Sodium Sulfite 0.14M
Ferric Ammonium EDTA 0.18M Ferric Ammonium EDTA 0.15M ~.
Mercapto Triazole 0.004M Mercapto Triazole 0.003M
.:
Bleach-Fix Replenisher 7 represents the one-
part replenisher solution that would be necessary to
yield Bleach-Fix Tank 8 (which is identical to Bleach-
Fix Tank 6 used in Table IV) assuming a replenishment
rate of 215 ml/m2 and a carryover of 32.3 ml/m2. Both
solutions, Bleach-Fix Replenisher 7 and Bleach-Fix Tank
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-19-
8 were stored at room temperature for 8 weeks. A
precipitate (Ferric Sodium EDTA) was observed in
Bleach-Fix Replenisher 7 but not in Bleach-Fix Tank 8.
These results demonstrate that a one part bleach-fix
s replenisher such as Bleach-Fix Replenisher 7 cannot be
used to replenish Bleach-Fix Tank 8 due to instability
of the replenisher solution. The present invention
circumvents this problem.
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.
" :
. . .
.
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