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Patented Oct. 8, 1946
2,409,107
UNHTED vSTTES PATENT OFFICE
2,409,107
PROCESSING OF CERTAIN NONGELATIN
EMULSIONS
-
John I. Crabtree and George T. Eaton, Rochester,
N. Y., assignors to Eastman ' Kodak Company,
Rochester, N. Y., a corporation of New Jersey
. ‘No Drawing. " Application October 16, 1942, .
.
v
>
Serial No. 462,233
4 Claims.
..
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1
p -
(01. 95_ss) ’ '
2
a
,
.
Organic thiocyanates such as vthiocyanocat
This invention relates to improved procedure
for the processing of photographic elements
‘which include an emulsion layer of apolyvinyl
inorganic thiocyanates. Examples of the most
geséin which is not readily permeable to processing
satisfactory thiocyanates which wehave tried
echol may be employed but we prefer to use
5 are sodium, potassium and ammonium thiocy
It is known to substitute polyvinyl resins for anate.‘ The thiocyanate can be added to, any
a
hs.
’
1
2
the gelatin in photographic emulsions. Poly
vinyl acetals such as polyvinyl acetaldehyde
'acetal, polyvinyl propionaldehyde aceta1 and
polyvinyl butyraldehyde acetal; polyvinyl esters
such as partially hydrolized polyvinyl acetate and
mixed polyvinyl acetal-esters are examples of
polyvinyl resins which have been used for this
purpose. See, for instance, Fordyce 2,211,323,
photographic processing bath utilized to treat the
photographic element, containing the vinyl resin
as above speci?ed.
m
Thus it can be added to
the conventional developing or ?xing bath. On
the other hand, it canbe used as a ?xing agent
per se. and in such case a conventional ?xing
vagent is unnecessary. ~
As indicated 'above our invention is applicable
Aug. 13. 1940; Lowe 2,253.078, Aug. 19, 1941; 15 to polyvinyl resin-containing emulsions generally.
Lowe 2,276,322, Mar. 17, 194.2; Lowe 2,276,323,
However, it is of particular advantage‘ in con‘
Mar. 1'7, 1942, and Lowe 2,236,215, June 16, 1942.
It will be noted that these patents specify cer
tain ranges of vinyl alcohol content which are
nection with the processingof polyvinyl resin
emulsions which have poor permeability to proc
essing
baths. ‘Thus polyvinyl esters which con
most permeable to photographic processing baths. 20
tain above about 71% of polyvinyl ester are slow‘
These patents also indicate that outside these
ly penetrated. Other, polyvinyl resins such as
the-acetaldehyde, butyraldehyde etc.v acetals are
in certain cases, especially in the higher acetal
25 content range.iimpermeable or slowly permeable
tional processing baths.
to processing baths. ‘Ourinvention is. therefore,
This invention has for its object to provide
of particular ‘advantage in‘ connection with the
improved methods for processing polyvinyl resin
treatment or processing ofs'uc-h emulsions. How
photographic emulsions. Another object is to
provide improved processing baths for photo
ever, it is applicable to emulsions which can be
ranges, and in certain cases inside certain por~
tions of these ranges, difficulty is encountered in
connection with lack of permeability to conven
graphic elements which include a layer of a poly 30 processed with conventional _--proce_ssing baths
vinyl resin which contains a silver salt and which
since the thiocyanate ~wil1<;increase the ratev of
penetration and rate of developing or ?xation.
is not readily permeable to usual processing
baths. A still further object is to provide a
Therefore. it is to be understood that the fore
method for treating an exposed photographic
going resins which are slowly or incompletely
element which includes a layer of a polyvinyl 35 penetrated constitute the preferred embodiment
of our invention.
resin containing a silver salt whereby its per
meability to the processing bath is increased and
The thiocyanates can be added to the develop
whereby the processing time is substantially re
ing and ?xing baths in greatly varying amounts
duced. Other objects will appear hereinafter.
depending upon the degree of permeability and
These and other objects are accomplished by 40 speed of penetration desired. For most purposes
our invention which includes treating an ex
between about one and one hundred grams per
posed photographic element including a layer of a
liter of processing solution will be found to be
polyvinyl resin which contains a silver salt and
satisfactory. For developing solutions we pre
which is not su?iciently permeable to the usual
for
to add about one to ?fty grams of thiocyanate
45
processing baths with a processing bath which
per liter of developer. For‘ purposes of ?xation
contains a thiocyanate. It has been found that
one to one hundred grams per liter are generally
the rate of penetration is greatly increased by
useful, but we prefer to employ thiocyanate in
the presence of this material in the processing
the upper portion of the range mentioned; i. e.,
bath and that the speed of development, ?xation,
about ?fty to one hundred grams per liter of
etc. is correspondingly increased.
?xing solution.
In the following examples and description we
In some cases it may be advantageous to add
an amine such as ethanol amine, triethanol
of our invention, but it is to be understood that
amine to the baths especially the ?xing bath, to
these are set forth for the purpose of illustra
55 avoid or prevent opalescence in the dried ?lm.
tion and not in limitation thereof.
have given several of the preferred embodiments
2,409,107
3
2 minutes at 70° F. The ?lm had good contrast
and was ?xed in 3 minutes by treatment with a
bath containing 100 grams of sodium thiocyanate
Example I
A silver halide emulsion was prepared by dis
persion of the halide in a polyvinyl acetaldehyde
and 100 cc. of ethanolamine per liter of 30 per
acetal which contained about 35 per cent unre Li cent hypo.
acted polyvinyl alcohol and this emulsion was
D-l6 developer is manufactured by Eastman
Kodak Company and is made up of the following:
coated upon a ?exible ?lm base in known manner
and photographically exposed. When treated in
Water, 50° C _______________________ __cc__ 750
a conventional developer such as diluted D-72
,Monomethyl-paraminophenolsulfate
(diluted 1 part developer to _2 parts water) the
development took place in ten minutes with poor
contrast.
grams__
The same ?lm exposed in the .same
.Hydroquinone __________________ __do____
6
NazCOa (£165.) ___________________ __do____ 18.7
way was developed in D-‘72 developer (diluted
1 :2) to which had been added 10 grams per liter
of sodium thiocyanate. The development in this
solution took place in two minutes and the con
trast was markedly improved. D-72 developer
is manufactured by Eastman Kodak Company
and is made up of the following:
Monomethyl-paraminophenolsulfate
grams"
3.1
.45
Hydroquinone ___._.___________.___do...__
12
NazCOs
(des) ___________________ __do____ 67.5
KBr ________ ____ ________________ __do____
1.9
Water to make ___________________ __liter__
1
'KBr ____________________________ __do____
.86
Citric acid__-_ ____________________ __do____
‘Potassium metabisul?te ___________ __do____
Cold water to make _______________ "liter"
.68
1.5
1
‘What we claim is:
Water, 50° C _______________________ ..-c;:.. 500 Y 20
Sodium .sul?te (des).____________.__'do____
.31
Sodium sul?te (des.) _____________ __do__.._ 39.6
'
1. The method of treating an exposed pho
g‘raphic element which comprises immersing the
element including a layer of a polyvinyl resin
which contains a silver salt and which ‘is not
readily permeable to processing baths, in a proc
essing bath which contains an inorganic thio
cyanate and ethanolamine.
2‘. The method of treating an exposed pho~
tographic element which comprises immersing
Example II
Film carrying 'the emulsion described in Ex
the element including a layer of a polyvinyl
resin which contains a silver salt and which is
ample I was exposed, developed and then ?xed in
a simulated conventional ?xing bath containing
not readily permeable to processing baths, in a
processing bath which contains an inorganic
30 per cent hypo. The rate of ?xation was 2
hours and '30 minutes. Addition of 100 grams of
sodium thiocyanate per liter of the '30 per cent
hypo reduced the time of ?xation to 3 minutes.
thiocyanate and an ethanolamine.
tographic element which comprises immersing
Example III
which is not readily permeable to developing
3. The method of developing an exposed pho
the element including a layer of a polyvinyl
acetal resin which contains a silver salt and
baths, in a developing bath which contains an in
Five grams of sodium thiocyanate per liter of
diluted developer D-72 (diluted, 1:2) developed
the photographic ?lm described in Example I in
2 minutes at 70° F. The developed ?lm had good
contrast. The ?lm so (developed was ‘?xed in .3
minutes by treatment with .a bath containing .100
grams sodium thiocyanateand .100.cc.,of ethanol
amine per liter of 30 per cent hypo.
Example IV
Five grams of sodium thiocyanate per liter of
diluted- D-l6 developer (diluted 1;2) developed
the photographic ?lm described "in‘Example I in
40
organic thiocyanate and ethanolamine.
4. The method of ?xing an exposed and. de
. veloped photographic element which comprises
immersing the element including a layer of poly
vinyl acetal resin which contains a silver image
and a silver salt and which is not readily ‘per
meable to ?xing baths in a ?xing bath ‘which .
contains an inorganic thiocyanate and ethanol
amine.
JOHN ‘I. CRABTREE.
GEORGE T. EATON.
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