U.S. patent number 3,617,283 [Application Number 04/636,669] was granted by the patent office on 1971-11-02 for simultaneous bleach-fixing method in color photography.
This patent grant is currently assigned to Fuji Photo Film G., Ltd.. Invention is credited to Hiroyuki Amano, Haruhiko Iwano, Reiichi Ohi, Kazuo Shirasu.
United States Patent |
3,617,283 |
Ohi , et al. |
November 2, 1971 |
SIMULTANEOUS BLEACH-FIXING METHOD IN COLOR PHOTOGRAPHY
Abstract
In processing photographic light-sensitive color material,
bleaching can be promoted without the occurrence of color stains by
incorporating, in a bleach-fixing solution containing a
water-soluble iron complex salt or a processing solution, between
color development and bleach-fixing a compound shown by the general
formula ##SPC1## Where R.sub.1 and R.sub.2 are an alkyl group, an
hydroxyalkyl group, an aryl group, or an allyl group, or R.sub.1
and R.sub.2 can form together a hetrocyclic ring, and R.sub.3 is an
alkyl group, an hydroxyalkyl group or an allyl group when R.sub.1
and R.sub.2 do not form a heterocyclic ring and is hydrogen, an
alkyl group or an hydroxyalkyl group when R.sub.1 and R.sub.2 form
a heterocyclic ring.
Inventors: |
Ohi; Reiichi (Ashigara-kamigun,
JA), Amano; Hiroyuki (Ashigara-kamigun,
JA), Iwano; Haruhiko (Ashigara-kamigun,
JA), Shirasu; Kazuo (Ashigara-kamigun,
JA) |
Assignee: |
Fuji Photo Film G., Ltd.
(Kanagawa, JA)
|
Family
ID: |
12246932 |
Appl.
No.: |
04/636,669 |
Filed: |
May 8, 1967 |
Foreign Application Priority Data
|
|
|
|
|
May 6, 1966 [JA] |
|
|
41/28377 |
|
Current U.S.
Class: |
430/393;
430/427 |
Current CPC
Class: |
G03C
7/421 (20130101) |
Current International
Class: |
G03C
7/42 (20060101); G03c 005/30 (); G03c 005/32 () |
Field of
Search: |
;96/6BF,61 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Torchin; Norman G.
Assistant Examiner: SuroPico; Alfonso T.
Claims
What is claimed is:
1. In the simultaneous bleach-fixing method of producing color
images from exposed photographic color materials using developers
which are capable of forming a silver and a color image, and a
bleach-fixing bath containing an iron salt of
ethylenediaminetetraacetic acid, the improvement which consists of
processing said materials at a point later than color development
but not later than the bleach-fixing step in a bath which contains
as the bleach-accelerating agent a water-soluble compound
represented by the general formula: ##SPC7##
wherein R.sub.1 and R.sub.2 each represents a member of an alkyl
group, a hydroxyalkyl group, and aryl group and an allyl group,
said R.sub.1 and R.sub.2 can form together a heterocyclic ring, and
R.sub.3 represents a member selected from the group consisting of
an alkyl group, a hydroxyalkyl group and a an allyl group when
R.sub.1 and R.sub.2 do not form a heterocyclic ring, and represents
a member selected from the group consisting of hydrogen, an alkyl
group and a hydroxyalkyl group when R.sub.1 and R.sub.2 form a
heterocyclic ring, whereby contamination of said color developers
by said bleach-accelerating agent has no substantial color-staining
effect during the color development.
2. The method as claimed in claim 1 wherein said compound is one
selected from the group consisting of: ##SPC8##
3. The process of claim l wherein at least one processing prior to
said bleach-fixing and subsequent to said color development is a
stop-fixing process.
4. The process of claim 1 wherein said water-soluble bleach
accelerating compound is present in said bleach-fixing bath in an
amount of from about 0.3 to about 5 grams/liter.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved bleach-fixing method in
photographic color processing.
Color processing, in general, consists of a number of steps, such
as, color developing, stopping, bleaching, fixing, hardening and
stabilizing, which need various chemicals depending on the
light-sensitive materials to be processed. Such processings are
carried out, for example, by passing the material to be processed
through a color developing bath, a stop fixing bath, a water
washing bath, a bleach-fixing bath, another water washing bath, a
hardening bath, a further water washing bath and a stabilizing
bath. The material may be passed through the successive baths by
leader belt and and roller means.
2. Discussion of Prior Art
Two typical bleaching methods in the processing of color
photography as mentioned above, are that of using potassium
ferricyanide and that of using a water soluble iron complex of
ethylenediaminetetraacetic acid. In the case of using the former,
the bleaching power thereof is sufficient to keep the picture
quality, but the bleaching bath and fixing bath must be separated,
because thiosulfate suffers decomposition from mixing with
potassium ferricyanide. Therefore, this procedure requires a longer
processing time.
Moreover, potassium ferricyanide tends to be converted into
potassium ferrocyanide. In the case of using the latter, on the
other hand, the bleaching and fixing power is not always
sufficient, but the coexistence of the oxidizing agent and
thiosulfate is possible. Therefore the bleaching and fixing can
proceed simultaneously in one bath. In this case, thiourea or its
derivative, as is well known in the art, may be added to the
bleach-fixing bath so as to increase the bleaching utility. When
adding thiourea or its derivatives to a bleach-fixing bath,
however, color stain often occurs from contamination of
bleach-fixing solution with the color developing solution. This
phenomenon has been proved to relate closely to the construction of
photographic materials and the type of photographic emulsions. For
example, the upper layer is more susceptible to color stain.
Therefore, in a color printing paper consisting of a red-sensitive
layer with a cyan coupler as the uppermost layer, a green-sensitive
layer with a magenta coupler as the middle layer, and a
blue-sensitive layer with a yellow coupler as the lowermost layer,
for example, cyan color stain occurs. Conversely, in a color
printing paper having a blue-sensitive layer containing a yellow
coupler as the uppermost layer, a green-sensitive layer containing
a magenta coupler as the middle layer, and a red-sensitive layer
containing a cyan coupler as the lowermost layer, yellow color
stain occurs. In a color positive film having three emulsion layers
in the following order, from the top, a green-sensitive layer
containing a magenta coupler, a red-sensitive layer containing a
cyan coupler and a blue-sensitive layer containing a yellow
coupler, a magenta color stain occurs. Such a phenomenon occurs
even in the presence of an extremely small amount of thiourea or
its derivative, for instance, a 10.sup..sup.-6 - 10.sup..sup.-7
g./1. color-developing solution thereof. Furthermore, it is nearly
impossible to prevent such color stain, since many of the thiourea
derivatives have absorptive properties and the elimination thereof
is very difficult.
Such color fog formation is observed in following cases although it
may also occur in many other cases.
1. When using a leader belt made of synthetic fiber, such as, nylon
in a continuous processing system as described above, thiourea or
its derivatives are absorbed on the leader belt and cannot be
completely eliminated during the processing steps after
bleach-fixing; that is, during the stages of washing, hardening,
final washing and stabilizing. Therefore, thiourea or its
derivatives, absorbed on the leader belt, enters into the color
developing solution, resulting in color stain.
2. Even in the processing using a developing tray, there sometimes
occurs the above-mentioned color stain if the color development is
carried out in a tray wherein a bleach-fixing solution containing
thiourea or its derivatives have been applied, or if the developer
accidentally happens to be contaminated even to a slightest degree
with the thiourea derivatives.
SUMMARY OF THE INVENTION
As a result of various studies or efforts to overcome this
disadvantage, that even the slightest amount of contamination of
thiourea or its derivatives results in color stain, it is found
that a compound (I) derived from thiourea, gives no color stain
even if it enters into the color developing solution, and
furthermore its ability to accelerate the speed of the bleaching
reaction is comparable to or better than that of thiourea. This
compound (I) is represented by the general formula, ##SPC2##
wherein R.sub.1 and R.sub.2 are alkyl, hydroxyalkyl, aryl and allyl
groups or they may be linked together to form a heterocyclic ring,
R.sub.3 is an alkyl, hydroxyalkyl or allyl group when R.sub.1 and
R.sub.2 do not form a heterocyclic ring, and hydrogen, alkyl group
or hydroxyalkyl group when they form a heterocyclic ring. The
compound (I) showed remarkable acceleration of bleaching reaction
in every case where it is added to a bath between the color
developing and bleach-fixing, or to a bleach-fixing bath
itself.
Illustrative of the compound of the foregoing general formula, used
in the practice of the invention, are the following, although it is
not limited thereto only. ##SPC3##
Compound 1 may be synthesized in the conventional manner by heating
ethylenediamine with carbon disulfide in a mixed solvent of water
and alcohol (Cf. Roger Adams, "Organic Synthesis" published by John
Wiley & Sons Co. Vol. 26, p. 34). Compound 2 and compound 3 are
similarly synthesized by reacting the corresponding diamine with
carbon sulfide. Compound 4 is obtained by reacting methyl
isothiocyanate with N-methyl-ethanolamine in ether, distilling the
ether and recrystallizing the residue from ethyl acetate. Compounds
5- 7 are synthesized similarly by reacting isothiocyanate R.sub.1
-N C S with the corresponding secondary amino compound R.sub.2
--NH--R.sub.3.
The amount of the foregoing compound to be added to bleach-fixing
solution is from 0.1 g./1. to the minimum dissolving amount of each
compound, preferably 0.3 g./1. to 5 g./1. These compounds may be
used separately or together.
The acceleration of bleaching reaction by the compound can also be
observed when it is added to any of the processing solutions
between the color development and bleach-fixing bath in an amount
within the range mentioned above.
PREFERRED EMBODIMENTS
The following examples illustrate the amount of color stain
produced when the compound mentioned above is added to a color
developing solution and the degree of acceleration of bleaching
when it is applied, but this invention is not confined to the scope
of examples. ##SPC4##
Thiourea (compound 8) and its derivative (Compound 9) that had been
used for bleach acceleration in the prior art, and the foregoing
Compound 1 to Compound 7 were respectively added to a color
developing solution containing
N-ethyl-N-.beta.-hydroxyethyl-p-phenylenediamine and dissolved
completely. A color printing paper was treated with thus obtained
color developing solution to give the following results. Cyan stain
was formed in this experiment. ##SPC5##
It is evident from the results that addition of the Compound 1 to
the Compound 7 of the invention amounting to 5'.times.
10.sup..sup.-2 g./1. did not result in cyan color-stain while the
cyan color-stain occurred in the case of Compounds 8 and 9 even
with the smaller amounts, 5.times. 10.sup..sup.-7 g./l. and
5.times. 10.sup..sup.-6 g./1. respectively. This means that, when
one of the bleach-accelerating agents (Compound 1-Compound 7) is
added to a bleach-fixing solution by the amount of 5 g. per litre,
no color stain will be observed even though the bleach-fixing
solution is carried over into the color developer to the proportion
of 10 ml. bleach per 1000 ml. developer. In this example, the
processing temperature was 24.degree. C. and the color developing
time was 6 minutes.
EXAMPLE 2
Compounds l- 9 were added to a color developing solution containing
N-ethyl-N-.beta.-hydroxyethyl-p-phenylenediamine and dissolved
completely. A color positive film was then treated with color
developing solutions respectively to give the following results.
##SPC6##
It is evident from the results that the addition of Compounds l- 7
of the invention amounting to 5.times. 10.sup..sup.-2 g./1. did not
result in magenta color-stain, while the magenta color-stain
occurred in the case of Compounds 8 and 9 even with their smaller
amounts, 5.times. 10.sup..sup.-6 g./1. In this example, the
processing temperature was 21.degree. C. and color development time
was 14 minutes.
EXAMPLE 3
Compounds 1- 8 of example 1 were added to the following
bleach-fixing solution by the amount of 2 g. per 1000 ml.
respectively. 1,000
11 Iron Salt of EDTA 34 g. Sodium Carbonate (monohydrate) 11 g.
Boric Acid 45 g. Sodium Thiosulfate 140 g. Additive 2 g. Water to
Make 1,000 ml. pH 6.8
a color paper was exposed, developed, fixed and then passed through
these bleach-fixing baths. The times required to remove the
developed silver were shown in the table below.
It is apparent from these results that the Compounds 1- 7 of the
invention have substantially the same bleach accelerating effect as
Compound 8 (thiourea). The processing temperature in this example
was 24.degree. C. When a color film was used in place of the color
paper, similar results were obtained.
EXAMPLE 4
Compounds 1- 7 of example 1 were added to the following stop fixing
solution in an amount of 1 g. per 1000 ml. respectively.
Sodium Thiosulfate 150 g. Sodium Sulfite 15 g. Boric Acid 12 g.
Glacial Acetic Acid 15 ml. Potassium Alum 20 g. Additive 0.1 g.
Water to Make 1,000 ml. pH 4.3
some test pieces of a color paper were exposed and developed, and
then fixed with each of the stop fixing baths containing our
compound. Another piece was treated similarly except that it was
fixed with the stop fixing bath containing no such compounds for
comparison. A clear difference in the bleaching speed between them
was found as follows:
It is apparent from these results that when the compounds of the
invention were added to a stop fixing bath, they accelerate the
subsequent bleach-fixing. In this example, the processing
temperature was 24.degree. C. and the stop fixing time was 2
minutes.
As another example of our invention, aqueous solutions of the
Compounds 1- 7 were prepared. Some test pieces of a color paper,
were exposed, developed, stop fixed, and then processed with the
bleach-fixing solution in the same manner as in example 3, but
containing no accelerator of our invention after immersing in each
of the above aqueous solutions. A clear difference between them in
the bleaching speed was found as shown in the following table.
It is apparent from these results that when processed with an
aqueous solution of the compound of the invention, the acceleration
of bleaching was observed in the subsequent bleach-fixing bath. The
processing temperature in this example was 24.degree. C.
When a color film was used in place of color paper, similar results
were obtained as expected.
* * * * *