US2305799A - Photographic material - Google Patents

Description

Patented Dec. 22, 1942 PHOTOGRAPHIC MATERIAL Otto Vierling, Dresden, Germany; vested in the Alien Property Custodian Application 3 Claims.

The invention relates to improvements in photographic material.

An object of the invention is to provide a photographic material permitting a picture to be produced thereon from a negative and having the distinctive characteristics that this picture may becaused to disappear again upon irradiation of the material with a light of certain wave length,

A process of producing pictures on phototropic material is described in the application Serial No. 118,372, for which Letters Patent No. 2,186,942 was issued on January 16, 1940, and of which the present application is a continuation-in-part.

A further object of the present invention is to provide a phototropic material of the character described in a form in which it can readily be used for the *production of the picture as wellas for the disappearance of the same.

It is also an object of the invention to provide an article of manufacture in which this material is supplied in predetermined shape in the form of a sheet ready to be positioned in the path of a light projected through a negative onto the material.

It had been proposed heretofore to make use of the phototropic qualities of fulgides' for the purposes set forth herein, but in these prior methods of producing pictures, the fulgides were used in the form of a solution of the fulgide in acetone, collodion or in the form of a solution of other solvents. In these prior processes the fulgides were used as dyestufis combined in their solutions with difierent catalyzers also preferably of liquid consistency. Catalyzers of this type, for instance, iodium or nitrobenzol, ,had been necessary in order to accelerate the bleaching out process just as the solvents for the fulgides had been believed to be necessary for the change of color of the fulgides in producing the picture.

As contrasted with these prior methods of uti lizing the phototropic material in solution and in combination with catalyzers of liquid consistency, the present invention makes use of the fulgide's or other phototropic substances in the form of solids.

With these and numerous other objects in view, theinvention is described under reference to the articles of manufacture constituting the subject matter of the present invention.

In the embodiment illustrated in l, the

accompanying drawing, wherein Figs. 1' to 5 show perspectively various embodiments of January 4, 1940, Serial No. 312,345 Germany December 31, 1935 paper, ground glass, fabric or the like,

'devices, enlargers and the like.

solid consistency by itself to permit its use in photographic equipment, as for instance, in copying apparatus, enlargers and the like, The layer I may be produced from the phototropic substance by fusion and subsequent hardening of the phototropic substance, or by compressing the substance into the form of a web or sheet or the like. Phototropic substances which can be used for this purpose are, for'instance, the fulgides, as triphenyl-fulgide-CnI-IwOa, or diphenylortho phenyl-fulgide. The normal color of these compounds is orange-red or red, and when exposed to blue light or blue-greenish light, this color changes into brownish-black.

Similar results are obtained when some of the compounds of the group of hydrazones are employed.

While in the prior methods of producing photoprints by means offulgides, the solutions of the fulg-ides were poured upon' a carrier and were subsequently sensitized by additions of phenetol or nitrobenzol, the present invention provides the fulgides in solid form ready to be used without requiring their being dissolved. In this manner the production of these articles of manufacture is greatly facilitated, as well as the method of using the articles.

In the embodiment illustrated in Fig. 2, the phototropic material in the form of a layer l is supported by a base 2. The ,phototropic material may again for instance be a fulgide, while" the base 2 may consist of paper, ground glass or the like. The layer I of phototropic material is permanently applied to the base by pressure owing to its inherent adhesiveness. The assembly of base and phototropic layer then constitutes the article of manufacture which is-the subject of the present invention.

In the embodiment illustrated in Fig. 3, the layer I of phototropic material, as for instance, fulgide, is associated with a base 2 by means of a binder 3 interposed between the base and the layer. The base again may be produced from and the binder may be a suitable, transparent, adhesive material of which many are gelatine or the like.

This combination of a layer of phototropic material free of catalyzers, solvents or the like, a binder and a base, constitutes a new article of manufacture in flat solid form which is particularly suitable for use in photographic printing Positives produced thereon through a suitable negative may again be caused to disappear rapidly when it is known in the art-a ufacture as well as the other embodiments described and illustrated in the present specification may be reutilired numberless times without their eifect being in any way weakened by the repeated radiations by the light which produces the pictures and by the light which causes the pictures to disappear.

The embodiment illustrated in Fig. 4 again consists of a flat sheet-like body 5 in which finely divided phototropic material 8, as for instance fulgides, is commingled with a binder material 1 adapted to harden, so that the compound article [constitutes a single homogeneous layer consisting of the carrier 1 in which the phototropic material I is uniformly dispersed. The binder or carrier 1 may be a substance which can readily be reduced to liquid consistency, remain hard at normal temperature. Gelatine, for instance, may constitute the material in which the finely divided phototropic may be dispersed in this manner. In this form also the new article of manufacture will be in condition for use without requiring the addition of solvents or catalyzers, and the production of the pictures as well as their disappearance is accelerated owing to the use of the phototropic material in uncontaminated condition, while the manipulations required in the use of the article are greatly simplified.

In the embodiment illustrated in Pig. 5, the layer I of phototropic material may be positioned between two protective plates I and II, as

for instance, glass plates or plates of other transparent material. The layer I produced by pression or fusion and subsequent hardening may but which will substance Y com- - vents, which would have a be applied to the protective plates I and II either by its own inherenttezttlihesiveness, or it may be pro ve plates of transparent material by a ransparent binder. It is obvious, furthermore, that instead of u a layer of the type illustrated mm. 1 between two'transparent protective plates, a layer of the pe illustrated inl'ig 4, maybeusedinwhichthephototmpicmaterial isiinely-dilpersed thin atransto harden at normal temperatures and having suiiicient inherent adhesiveness to unite this Iayerwiththe protective plates 8 and II.

In all of the embodiments illustrated, it is the I phototropic material as such which serves to receive the picturesand which is adapted to per-' mit the pictures to be removed theretrosn by radiation. Owing to this utilization of the phototropic material in the form of a coherent solid layer with or without any support, the production of the new article of manufacture also is, less costly than the production of a phototroplc material by solution in a suitable solvent and the addition of catalyaers which render this solution suitable for receiving the pictures. The catalyzers previously used in association with fuigides were photoactive substances, and the ful. gides in themselves merely served as dyestuffs for these catalyzers to render the effect more noticeable; As contrasted with these prior materials, in the present invention it is the fulgide itself (or some other phototropie material as a compcimd of the group of hydrazonesl in solid form andfree from oatalyzers which accelerates the action and the article is free from action.

The article can be produced in all suitable sizes, and placed at the disposal or the public just as plates or iilms for ordinary pho ographic material. a V

sheetiirmlyunited withasupportingtransparentbaseoffiatsheet-likefom' 3. As a new article of manufacture, pure fulgide. free of catslysers and the form of a solid coherent sheet, and a transparent protector plates below and saidiayerandtowhichsaidlayeris (71'1'0 VIIRHRG.

ingredients, as sol-. tendency to retard the

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