US1879806A - Photographic film - Google Patents

Description

Sept. 27, 1932.

w. vf' D. KELLEY 1,879,806

PHOTOGRAPHIC FILM Filed Feb. 14, 1951 PWM Patented Sept. 27, 1932 UNITED STATES WILLIAM V. D. XELLEY, OF HOLLYWOOD, CALIFORNIA.

PHOTOGRAPHIC FILM Application led February 14, 1931. Serial No. 515,747.

In thisspecilication, and the accompanying drawing, I shall describe and show a preferred form of my invention, and specifically mention certain of its more important objects. I do not limit myself to the forms disclosed, since various changes and adaptations may be made therein without departing from the essence of my invention as hereinafter claimed; and objects and advantages, other than those specilically mentioned, are included within its scope.

This invention relates to color-photography and its principal object is to provide an improved type of sensitized film for use in this art.

In the accompanying drawing I have illus- .trated two embodiments of my invention,

thus:

Figure 1 is a diagrammatic cross section of a film of my new and improved type comprising, a single pan-chromatic or other photosensitized emulsion that is uncolored, and a colored photo-sensitized emulsion superposed thereon; and

Figure 2 is a diagrammatic cross section of another film that embodies my invention and which comprises, two uncolored color-selective photo-sensitized emulsions, and a colored photo-sensitized emulsion interposed therebetween.

Similar reference numerals refer to similar parts throughout both figures.

In the manufacture of films for color-photography and especially those intended for film pack use, where it is desired to apply a colored layer to the surface of a photosensitized emulsion, or where it is desired to separate two photo-sensitized emulsions by an interposed colored layer, the best result has been attained hitherto by the use of simple colored gelatine for the colored layer. It is not very feasible to color the surface of photosensitized emulsions by directly applying dyes in water solutions, since the time required for such solutions to penetrate the emulsions to a sufiicient extent is far too great for practical purposes. Such treatment requires more time than standard machines are equipped to give, and would necessitate the use of special laboratory equipment. There'- fore the practice has been to apply a layer of simple colored gelatine overthe photo-sensitized emulsion for the production of films of this general type.

Difficulties have been experienced in the use of films that employ coatings of simple, colored gelatine over photo-sensitized emulsions. The colored gelatine layer, notwithstanding the fact that it may be very thin, is sufiiciently thick to prevent obtaining the 6o very sharp focusing that present practice requires, especially when two photo-sensitized emulsions are used face to face as a lilm pack.

In such cases the light rays must traverse the insensitive layer of dyed gelatine, which is a 65 medium that usually has a different refractive index from that of the sensitized emulsion. This causes the rays to partially break up and scatter, and results in lack of sharpness of the image. The passage of the light 10 rays through the insensitive layer is also accompanied by some absorption, and possibly diffraction, and such effects add to the difficulties mentioned.

I have discovered that the above mentioned diiculties may be very nearly if not entirely overcome, and that a tremendous practical advantage may be gained, from the use of a sensitized dyed layer over an emulsion, or between two. emulsions, in place of the hitherto used insensitive colored layer. To secure the best results, the dved layer should preferably be composed of the same sensitized emulsion material as that of the underlying emulsion, but with the necessary amount of dye incorporated therein. The two emulsions are made to practically coalesce in this manner, and the result is substantially the same as if dye had been caused to penetrate only the outer portionof a single emulsion by immersion, in the manner described in British Patent #$33,933. My. method however, hasA the great advantage over hitherto known processes, of affording an exceedingly uniformly dyed portion near the surface, the density of the dye being whatever is required, and the thickness of the dyed portion being just as desired and very uniform.

In the two figures of the accompanying drawing, I have indicated Celluloid, glass, or other base material at 5, and a thin layer of photo-sensitized emulsion containing a dye, at 6. In Fig. l, I have shown an uncolored photo-sensitized emulsion of any type at 7. In Fig. 2, I have shown at 8 an uncolored photo-sensitized emulsion that is color-selective; and at 9 an uncolored photo-sensitized emulsion that is color-selective to a comple- :o mental color as compared to emulsion 8.

It will be obvious that the dyes used in my improved type of film should be such as do not readily wander from the dyed layer to the undyed layers in contact therewith.

Such dyes are those known to commerce as direct dyes, vof which Congo red and eiroglancime are prototypes. Or suitable dyes may be mixed with the photo-sensitized material of layer 6 after making an alcoholic 2o solution of them, as, for instance, a mixture of chrysoidine and safranine. Such dyes, used in this way, do not tend to wander.

It will be seen, from the foregoing, that my invention aords ready facilities for constructing many kinds of photographic film for color-photography, in which the light rays arenot required to pass through an insensitive layer at any point; and in which, as a consequence, most, if not all of the ob] ec- 3o tionable eects of refraction, diffraction, and inability to obtain sharlp focusing, are not encountered. Any of t e usual sensitizing means may be employed, such as the use of silver halides.

Having thus fully described my invention,

I claim:

1. A photographic film adapted for bi-pack photography, consisting of; a layer of photosensitized material that is insensitive to red light, coated upon a transparent base; and

a separately coated layer of like photo-sensitized material over the rst said layer; the material of lsaid second layer having a dye incorporated therein, and adherin thereto in such manner that it cannot blee into the first said layer.

2. A photographic film adapted for colorphotography, consisting of; two separately applied superimposed layers of photo-sensitized gelatine material; both of the layers being insensitive to red light; one of said layers being without light-ltering color; and the other layer containing a light-filterl ing color attached tothe gelatine, and adapt-v ed to act as a color iilter; the last said layer being thinner than the rst said layer.

WILLIAM V. D. KELLEY.

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