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Патент USA US2403721

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July 9; 1946. '
E. E. JELL-EY ETAL
2,403,721
PREVENTING COLOR FOG IN PHOTOGRAPHIC MATERIAL
Filed Sept. 23, 1943
15
EABLE LAYER CONTAINING
_ REDUCING AGENT
Yl-ELLOW FILTER
EMULSION LAYERS
CONTAINING COUPLERS
‘SUPPORT
EDWIN E. JELLEY
PAUL W. VITTUM
INVENTORS
,BY W?m/
6a \7
‘ ATTORNEYS
2,403,721
Patented July 9,- 1946 7.
UNITED STATES PATENT oFncE I M
2,403,721
PREVENTING COLOR FOG IN PHOTO
‘
GRAPHIC MATERIAL
- Edwin E. J elley and Paul W. Vittum, Rochester,
N. Y., assignors to Eastman Kodak Company,
Rochester, N.'Y., acorporation of New Jersey
v
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"Application, september 23, 1943, Serial No. 503,472 "
5 Claims.
.
1
(.01. 95-8)
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This invention relates to color photography and
particularly to a‘method for preventing the for
,
reducing agent capable .of reacting with the oxi
dized developer in the‘ developing solution to yield
substantially colorless products. The oxidized de
veloper present ‘in the developing solution is
thereby prevented from reaching the sensitive
layers containing couplers and combining with
the couplers where the layer was not exposed.
mation of color fog 0r stain in photographic
emulsions containing couplers.
The method of color photography in which col
or-forming or coupling compounds combine with
the development product of aromatic amino pho
tographic developers to produce dyes ‘is Well
known. The color formers or couplers used in'
The unoxidized developing agent can penetrate
7. through the layer containing the reducing agent
this method may be added directly to the sensi;
tive emulsion layers as described in Fischer U." S.v
unaffected, and develop thev exposed portions of
the emulsion layer or layers to form colored im
Patent 1,102,028, granted June 30, 1914, or may
ages therein.
be incorporated in a water-permeable medium
which is insoluble in the colloidal carrier 'for the
sensitive silver salt as described in Mannes & Go
dowsky U. S. Patent 2,304,940,‘,granted December
15,‘ 1942,01‘ our‘ U. '8. Patent 2,322,027,‘ granted
June 15,
1943.
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In the accompanying drawing the single ?gure
is a sectional view of a ?lm constructed according
to our invention.
In
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The water-permeable layer containing the re
ducing agent used according to our invention is
coated over the sensitive-‘emulsion layer of the
"
' A di?iculty' ‘frequently ~encountered‘in "these
photographic material. The overcoating layer
processes is the formation of color fog or stain. 20 may be used with single layer photographic ma
When the exposed material is developed in a col
terials althoughit'is of-igreater value with multi
or-forming developer, ‘dye fog‘ is ‘frequently
layer materials containing couplers in onevor '
formed in the emulsion layer. " This is because
more of the sensitive emulsion layers such as
the developing agenthas been ‘oxidized to some
those described in the Mannes & Godowsky U. S.
exte'ntby the ‘action'of ,thejair and the oxidized 25 Patent 2,304,940 or our ;U.. s. Patent.2,322,027,,
developer't‘endsfto couple with the color-forming
referred to above.
compound'at pla‘ces'in the photographic material‘
where no' silver image is produced‘.
‘It is Well
an opaque base.
knownthat in thes'e'processes'the‘dye should‘be
I
In the case of a ?lm material, the e?ect of the
formed ‘only where they silver halide "is reduced‘to
extra layer containingthe reducing agent is to
metallic “ silver,‘ thereby oxidizing ‘the ‘ developing
render the developer di?using through it sub
agent toa form'which coupleswith the 70010;‘
stantially free, from oxidation products which
would otherwise -.cause'color fog. With paper
materials, most of the di?usion takes place
through the emulsion sidev‘so; that the overcoat
ing'layer is usually adequate for preventing stain.
However, there might be'a slight gain in freedom
from color iog‘in therlowermostvsensitive layer
former. . Once the developing agent is oxidizei'it
couples immediately'with'the color former whethl'
er a photographic image is present or not. ‘ Aerial
oxidation ,of' the developer‘ or’oxidation by means
other than the photographic image therefore con;
verts the developer to a form whichiwill immedii
ately‘react with the‘color' formert'o' produce ‘a
, of ‘a paper coating if a layer were placed between
it and the paper base containing a substantially
color‘fog or stain.‘ This‘ e?ect is especially no:
ticeable' in materials having couplers'incorpo
rated in the‘sensitive emulsion'layer since ‘there
is no coupler in‘ the developing solution ‘to react
non-di?using reducing agent capable of destroy
ing developer oxidation products.
The overcoating layer used according to‘ our
invention may consist of any (suitable water-per
with any developing'agent which-is oxidized‘by
the action of the air. Fog or stain arising from
4. 5
these causes is not readily centrolled‘by the same
procedures used to control‘silver fog.‘
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c It is an object of_ the presentyinvention to pre
caused by the oxidizedv developer penetrating the
upper‘? layers of‘ a multilayer photographic ‘ma-g
meable colloidal material such as gelatin, col
lodion or other cellulose ester. or synthetic resin
such as polyvinyl alcohol. 4 "A suitable amount of
a reducing agent is added to the colloidal ma
terial which is coated as a layer on the ?nished
vent that particular type ,of color fog which is
50 ?lm.
terial containingcouplers, “ A lfu-rther'object‘is to
The reducing'agent'should be non-di?us
ing in the layer in which it is'incorporated so
that it does not contaminate the adjacent sensi
provide a sensitive photographic material- con:
tive emulsion layer.
taining couplers 'and provided ‘with an ’ overcoat-y
ganic reducing agent containing an aliphatic
ing layenwhich'affords ‘protection against such:
.
The‘sensitive material may
be ?lm or paper and mayhave a transparent or
_>
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V
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._
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,
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.
We prefer to use an or
group having a carbon chain of at least 8 carbon
atoms, such as a higher'fatty‘acid residue. Hy
" These objects ;are accomplished‘, . according to
droquinones having long chain aliphatic groups
our inventi0n',"by providing overfthe' multilayer‘
are especially‘suitable although we‘may also use
material .a _ layer of va ,waterep'ermeable "colloidal .
p-aminophenols, hydrazines Or ascorbic acid de~
material‘ containing a substantially non-‘diffusing 60
rivatives.
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2,403,721
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3
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if M 3
The reducing agents for lowering color fog
The following compounds, which are by way
may be incorporated directly in the gelatin or
other colloidal material of the overcoating layer
of example only, are suitable for use according to
our invention:
or may be inconporated in a water-permeable,
water-insoluble vehicle which is dispersed in the
gelatin or other colloidal carrier.
The method
, of incorporating the reducing agent will be ex
' lplained by reference to the following examples.
Example 1
10
A solution‘ of 2 grams of didodecyl hydroqui
n-Octyl hydroqulnone
none in a mixture of 130 cc. of 95% ethyl alcohol
and 10 cc. of 20% sodium hydroxide solution was
added to 1000 cc. of melted 5% gelatin solution.
15 To this solution there was added sufficient citric
on
Cal a-Q0631"
' '
acid solution to bring the pH to the desired value,
for example, about pH 6.5. The mixture was
then ‘coated on a multilayer material containing
n
couplers.
Di-n-octyl hydroquinone
20
»
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‘Example 2
OH
I
A solution containing 4.5 grams of p-lauryl
phenyl hydrazine and 10 grams of n-butylphthal
>
ate in 200 cc. of ethyl acetate was emulsi?ed with
25 400' cc. of 0.5% aqueous solution of triisopropyl
naphthalene sulfonate. The emulsi?cation was
QCHHH
effected by passing the mixture several times
through a colloid mill. The resulting emulsion
n-Dodecyl hydroquinone
f
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0H
.
was subjected to heating on a ‘steam bath with
30 constant stirring to dissolve, off the ethyl acetate
and the remaining water suspension was added
to 500 cc.‘ of melted 10% gelatin.
mixture
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- _
Callas-$01211“
,
H
was diluted with water to one liter and was then
coated on a multilayer material containing cou
35
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piers.
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Our invention will now be described by refer
Dl-n-dodecyl hydroquinone
ence to the accompanying drawing.
.
As shown, in the drawing, which is a sectional
view of a ?lm constructed according to our in—
40 vention, I0 is a support of cellulose ester or other
suitable material having thereon gelatino-silver
halide emulsion layers ll, l2 and I3 sensitive, re
spectively, to the red, green and blue regions of
the spectrum. Emulsion layer. 1 l contains a cou
‘ OctadecyI hydroquinone'
45 pler capable of producing a cyan dye image upon
development, emulsion layer I2 containsv a cou
0H
pler capable of producing a magenta dye image
upondevelopment, and emulsion layer’ l3 con
tains a coupler capable of producing a yellow dye
. CmHns
50 image upon'development.
Ol—-
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as
Chloro-n-dodeoyl hydroquinone
on
7
Q0 020mm,
.
H
Suitable couplers are
described in Mannes 8: Godowsky U. S. Patent
2,304,940 or our U. S. Patent 2,322,027. The usual
yellow?lter layer H1 is employed between layers
l2 and I3 to prevent action of blue light on the
55 layers It and I2; Overv the layer l3 there is a
gelatin layer [5 containing ‘a reducing agent
which is non-diffusing’ in the gelatin.
fact that the reducing agent is substantially non
.
di?using, agents may be used which could not be
added to an emulsion layer becauseiof fogging,
desensitizing or interfering with normal dye
Lauryl gentisate
on
65
ONHC 0 cum:
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In our process the reducing agent is located
in its own separate layer away from thesensitive
60 silver halide. For this reason, together with the
.
2-lauroylamino-4-aminophenol '
image
formation.
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The reducing power of- the reducing agents
used, according to our invention, may be’ deter
mined by reference to their action on a solution
of ammoniacal silver nitrate.
A solution of am
70 moniacal silver nitrate is prepared by making a
116 normal solution of silver nitrate and adding
to it a 28% solution of ammonium hydroxide
p-lllaurylphenylhydrazine
slowly until the ?rst formed precipitate just dis
solves. The compound to be tested for deter
75 miningits suitability for use in our invention‘ is
2,403,721
5
hydroquinone non-di?using in said water-per
then added to the ammoniacal silver nitrate so
lution. If it reduces the silver nitrate immedi
ately and without heating, to metallic silver, it
meable colloid layer.
is suitable for use according to our invention.
support having thereon at least one silver halide
It will be understood that the examples and
modi?cations included herein as by way of ex
said emulsion layer a layer of a Water-permeable
ample only and that our invention is to be taken
as limited only by the scope of the appended
an aliphatic group having a carbon chain of at
l
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3. A multilayer photographic ?lm comprising a
emulsion layer containing a coupler, and over
colloid containing a hydroquinone having therein
least 8 carbon atoms.
.
10. 4. A multilayer photographic ?lm comprising a
We claim:
support having thereon at least ‘one gelatino
1. A multilayer photographic film comprising a
silver halide emulsion layer containing a cou
support having thereon at least one silver halide
pler, andover'said emulsion layer a layer of gel
emulsion layer containing a coupler, and over
said emulsion layer an outermost, exposed layer > atin containing a hydroquinone having therein an
of a water-permeable colloid containing an or 15 aliphatic group having a carbon chain of at least
claims.
ganic reducing agent for oxidized photographic _
_8 carbon atoms.
5. A multilayer photographic ?lm comprising a
developers, said reducing agent containing an ali
support having thereon at least one gelatino-sil
phatic group having a carbon chain of at least,
ver halide emulsion layer ‘containing a coupler,
8 carbon atoms and being non-diffusing in said
water-permeable colloid layer.
20 and over said emulsion layer a layer of gelatin
containing a hydroquinone substituted with an
2. A multilayer photographic ?hn comprising a
alkyl radical having a carbon chain of at least 8
support having thereon at least one silver halide
carbon atoms.
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emulsion layer containing a coupler, and over
‘
EDWIN E. JEILEY.
said emulsion layer a layer of a water-perme
PAUL W. VITTUM.
able colloid containing a hydroquinone having at 25
tached thereto a substituent group rendering said
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