US2075144A - Antihalation layers for photographic plates and films - Google Patents

Description

March 30, 1937. w. SCHNEIDER ANTIHALATION LAYERS FOR PHOTOGRAPHIC PLATES AND FILMS Filed oct. 15. l19:51

Supponi- Patented Mar. 3o, 1931 2,075,144

UNITED STATES PATENTA OFFICE ANTIHALATION LAYERS FOR PHOTO- GRAPHIC PLATES AND FILMS Wilhelm Schneider, Dessau, Germany, assigner 'to Agfa Ansco Corporation, Binghamton, N. Y., a corporation of New York Application October 15, 1931, Serial No. 569,067 In Germany October 31, 1930 My present invention relates to anti-halation Suitable compounds for the aforesaid purpose layers for photographic plates and lms, and 'are likewise diarylmethanes of the kind described more particularly to a protective layer for an Which bear besides'a carboxyl group or hydroxyl anti-halation layer applied on the back lof such group a hydroxy alkyl group. Furthermore it is 5 plates and films. not necessary that the diarylmethyl compounds One of its objects is to provide a process of prein question are built up symmetrically; one of the venting particles to lsplit from the color layer by nuclei may be substituted if at all by substituents Coating the said layer With a protective layer. otherthan those attached to the other nucleus. Another object are the new plates or lms being The coating material is usually applied in a provided with such an improvedv anti-halaton thickness of 0.5-2 which is completely sumcient 1o` layer. Further objects will be seen from the defor protecting the dye-containing anti-halation tailed specification following hereafter. layer from being mechanically damaged.

The known anti-halation layers applied on the In order to apply the coating material it is back of photographic plates and films frequently dissolved in a non-aqueous solvent. Aliphatic deliver colored particles when mechanically alcohols have proved to be suitable solvents espe- 15 stressed, which deposit in the picture taking cially those containing 1 to 5 carbon atoms.

apparatus and, when they come on the light- 'Ihe coating layer can easily be removed, it Sensitive layer, Cause SpOts by masking the light being soluble in the usual photographic developers or by chemical influence. within about 30 to 40 seconds. vIt may be men- Now I have found that the said drawback can tioned that those derivatives of diarylmethane be avoided by providing the anti-halaton layer, which contain only hydroxyl groups more easily containing a colored anti-halation material diss01ve in developers having a, strong alkaline which is permanently removable by an alkaline reaction, while derivatives of diarylmethane condeveloper bath, with a colorless coating which taining carboxyl groups dissolve in both kinds comprises a diarylmethane derivative containing of developers, those having a strong or those at least one hydroxyl group or carboxyl group in having a weak alkaline reaction. a nucleus. The following compounds are, for The following examples illustrate my inveninstance, suitable: tion:

. CH l l. A solution of 1 gram of the ammonium saltv T of polyglucuronic acid and 1 gram of fuchsine in 30 (l) 100 cc. of Water is applied on a nitrocellulose film.

OH/ j \0H After drying, the anti-halation layer thus ob- (IJOOH 00H tained is coated with a 'solution of 4 grams of dihydroxydiphenylmethanev dicarboxylic acid (see Formula 1) in 100 cc. of ethanol. 35

on 0H 2. A cenmcse acetate mm is provided with an CH anti-halation layer from a solution of 2 grams of (2)v i y gum arabic, 1 gram of methyl blue, 50 cc. lof

H3 HI on on on ethanol and 50 cc.,of water. After drying, the

grams of dlhydroxydimethyldiphenyl-methane (Formula 2) in 100 cc. of propanol. 4 The quantities of coating solution indicated in CH -GH the examples allow to coat a. surface of about 2 (3) to 3 square meters. 45

It is to be understood that my invention is not limited to the foregoing examples norto the cn. specic detalls given therein. Other suitable colorless coating materials of the kind described (13H3 HB The gure represents a sectional view of a photo- 55 graphic plate' prepared according to my inveni 55 anti-halation layer is coated with a solution of 5 40 0H on 0H V cooH\ are considered to be equivalents of those men- 5o CH- CH COOH t tioned. Other alcohols than ethanl or propanol (4) likewise may be used. The annexed drawing illustrates my invention.

H: Ha I Ha.

tion. In this ligure' I is the glass plate which serves'as support, 2 is the emulsion layer, 3 is the color layer forming the anti-halation layer on the back of the plate, and l is my new coating layer 5 preventing particles of being split off from the color layer.

What I claim is: 1. Photographic plates or films provided on their rear side with an anti-halation layer, said 10 anti-halaton layer'being coated with a protection layer comprising a derivative of a diarylmethane substituted with at least one radical of the group consisting of -OH and --COOHl 2. Photographic plates or lms provided on 15 their rear side with an anti-halation layer, said anti-halation layer'being coated with a protec-l tion layer comprising dihydroxydiphenylmethl ane-dicarboxylic acid.

3. 'Photographic plates or iilms provided on 20 their rear side with an anti-halation layer, said anti-halation layer being coated with a 'protection layer comprising dihydroxydimethyldiphenylmethane.

4; Photographic plates or iilms comprising a support bearing on one side a light-sensitive emulsion layer and on the rear side a solid anti.- halation layer containing a colored anti-halation material which is permanently removable `by an alkaline developer bath, said anti-halation layer being coated with a protective layer which is insoluble in water but soluble in an alkaline developer bath.

5. Photographic plates or lms comprising a support bearing on one side a light-sensitive emulsion layer, and on the rear side, a solid antihalation layer containing a colored anti-halation material, which is permanently removable by an alkaline .developer bath, said anti-halation layer being coated with a protective layer, which is insoluble in water but soluble in an alkaline developer bath within about -30-40 seconds.

WILHELM SCHNEIDER.

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