US1768795A - Dye-carrying layer for photographic films and the like - Google Patents

Description

y 1, 1 -s. E. SHEPPARD ET AL 1,768,795

DYE CARRYING LAYER FOR PHOTOGRAPHIC FILMS AND THE LIKE Filed March 1, 1929 CeZZuZasio sq voril 5 EQvILTZyZ aZca/zob ZZZCZZZCZZVQ Jase/255K227 and ZzyhZ-resiraz'nz'zzydyea Smzztshe ard/ &Jm5 amzvzzg,

IN V EN TORS,

sy'fiwi mx" ATTQRNEY' Patented July 1, 1930 UNITED STATES PATENT oFncE SAMUEL E. SHEPIBARD AND JAMES G. MCNALLY, OF ROCHESTER, NEW YORK DYE-CARRYING IIAYER FOR PHOTOGRAPHIC FILMS AND THE LIKE Application filed March 1 This invention relates to' anti-halation and desensitizing coatings for'photographic films and plates.

' One source of trouble encountered 1n all photographic work is halation, that 1s the reflection of rays upon the rear surface of the emulsion layer from the rear surface of its support, such as cellulosio film or glass.

It has been proposed to overcome this difficulty by applying, to the rear surface of the support for the photographlc emulsion, a layer of dye which is absorptive of light of the wave length to WhlCll the emulsion is sensitive. Since the exposed surface of this dye layer is frequently roughened 1n the process of applying 'it to the support, it becomes necessary to polish 1t so'that there may not be a prohibitive amount of friction between the film and the parts which it en- 2 counters in moving through a projector.

- It has also been .proposed to incorporate such a dye in a colloid or other carrier layer but in the past many such carrier layers have been open to the objection that they 5 were not instantly soluble and tended at first to become gummy so that if the film was processed in a continuous automatic machine, such softened carrier layer would separate from the film and collect on the rolls and sprockets of the machine.

In accordance with one feature of the present invention it is proposed to apply an anti-halation dye-carrier layer on the rear surface of a support for a photographic emulsion, said layer being formed of a material which may be applied to the support as a continuous film having a smooth surface and in which there is incorporated an absorptive dye for the actinic rays.

to the use of a desensitizing dye in a carrier layer 'of polyvinyl alcohol applied to a photographic film or plate so that it may be used in a rocess of daylight developing.

An additional feature of the invention is Another feature of the invention relates- 1929. Serial No. 343,764.

the incorporation of a desensitizing dye with the absorptive dye .in the carrier layer applied to the support for a photographic emulsion so that it may be used in a process of daylight developing. A further feature of the invention is the use of polyvinyl alcohol or oxy ethylene with an absorptive dye therein as an anti-hala tion coating for photographic films and plates. 55,

Other features will appear from the description and claims.

We have discovered that the synthetic product, polyvinyl alcohol or oxy ethylene, as prepared by H. Staudinger (Ber. 59, p. 3069, (1926)) and also by W. O. Herrmann and W. Haehnel (Ber. 60, p. 1658, (1927)), may be used to form a valuable anti-halationsupport for photographic plates and films. This material is soluble to colloidal 6 solutions in water, which can be precipitated by alcohol. The solution in water at a concentration of 10% can be coated in a known manner, similar to the coating of starch paste, sizes,'and the like, on the back of pho- 7 tographic films and plates, forming a glassclear, continuous film, which read1ly redissolves in water or in the. aqueous solutions usedpin photographic processing. If this solution has admixed with it a dye or other material which is opaque to photographicah ly active rays, there is obtained a. valuable anti-halation layer which is rapidly and completely discharged by the photographic bath. The coating may also be made so with colloidal manganese oxide in place of a dye, or the anti-hala'tion dye may be coinbined with a desensitizing dye, so that on dissolving in the developer a process of daylight developing is immediately secured.

While We do not intend to limit our invention to the use of any particular dye, we have found that the polyvinyl alcohol has the capacity of holding without crystallization in the dry film, the following anti- D0 halation dyes in amounts up t5 10% of the weight ofthe polyvinyl alcohol: Auramine. Ponceau 6R Helianthin Crocein Scarlet Brilliant Yellow S Diamond Black Chrysoin Azorubin Crystal Violet Likewise polyvinyl alcohol also has the capacity for carrying up to 10% of its own weight of any of the following desensitlzing dyes lhenosafranin Pinakryptol Green Nile Blue Pinakryptol Yellow Aurantia Jute Red Basic Scarlet N Thio Flavin T All of the above mentioned dyes are listed in the recognized tables, such as those published by Gustav Schultz, Berlin, 1923.

Although it is believed that it is obvious how the present invention may be used in preparing photographic material, reference is made to the drawing in which 1 designates a transparent support such as celluloslc film or glass on which there is placed a coating 2 of sensitized photographic emulsion. On the rear surface of the support 1 there is placed the dye-carrying layer 3 which prevents halation and which may also be used to carry a dye permitting a process of daylight developing. This layer may have incor orated therein, amounts previously speci ed of any one of the mentioned anti-halation dyes or the anti-halation colloidal manganese oxide or any one of the desensitizing dyes.

What we claim is:

1. An article of manufacture comprising a transparent support, a coating of sensitized photographic material on one side of said.

support, and a layer coated on the other side of said support formed of polyvinyl alcohol and a material absorptive of the light rays towhich the photographic coating is sensitized.

2. An article of manufacture, comprising a transparent support, a coating of sensitized photographic material mounted on one side of said support, and a dye-carrying layer comprising polyvin 1 alcohol mounted on the other side of sai support. v

3. An article ofmanufacture, com rising a transparent su port,.a coating 0 sensitized photographic material mounted on one side of said support,and a coating for the other side of said support comprising poly vinyl alcohol and including an anti-halation dye in amounts up to 10% of the weight of the dry polyvinyl alcohol.

4. An article of manufacture-comprising a transparent support, a sensitized photographic coating mounted on one side of said support and a'layer mounted on the other s1 e of said support formed of polyvinyl day of February, 1929.

SAMUEL E. SHEPPARD.

JAMES G. MCNALLY.'

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