US822532A - Photographic plate for color photography. - Google Patents

Description

o. 822,532 PATENTED JUNE 5, 190

A. & L. LUMIERE. I PHOTOGRAPHIG PLATE FOR COLOR PHOTOGRAPHY.

APPLICATION FILED NOV.22,1904.

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PHOTOGRAPH) PLATE FOR COLOR PHOTOGRAPHY.

Specification of Letters Patent.

Patented June 5, 1906.

Application filed November 22, 1904. Serial No. 233,851-

To k1]? whom 1'2- may concern.-

Be it known that we, Atcus'rn Lmniznn and LOUIS Ltnnimn, citizens of France, re-

at Lyon-Monplarsrr, Rhone, France, 1

siding invented new and useful Improve ments in Photographic Plates for Color Photography, of which the following is a specification.

The present invention has for its object to the preparation of sensitive plates giving colored pictures by means of simple manipulations analogous to those which are practically effected in ordinary photography in black. These plates are c 1aracterized by the sensitive coating and the glass which serves as its support of a screen-coating formed of colored particles prepared in the following manner: The colored particles are grains of starch, ferbacilli, pulverized enamels, or other pulverulent and transparent materials. They are colored by means of colors also transparent in orange, green, and violet, or else in red, yellow, and blue, or even in '30 surface of the plate any appreciable coloration. These colored particles may be employed in various 'manners.

The accompanying drawings, considerably enlarged, represent one of them byway of Figure 1 shows in section a sensitive plate prepared by one of these means. Flg. 2 shows in plan the arrangement of the colored particles.

0 The arrangement shown is obtained with articles colored in orange, green, and violetand mixed in convenient proportion so as to offer no sensible coloratio On one face of a plate of gl: ss a is spread a 45 cozting b of transparent pitchy matter, upon which is ap' lied the mixture of colored particles, whic is brushed in such a manner that the grains which remain fixed thereon touch each other. without being superposed ous as possib e. To obtain am much as possible this continuity, the operation is commenced by sprinklmg the plate with relatively large particles'e e, Fig. 2. Then when 25 any number of colors. such that the grains will be made in those the particles have no common.

this operation is terminated a second sprinkling will be effected-with smaller particles e e of like color to the preceding, which will lodge in their interstices. Then, if required, the spaces which may still exist can be filled by a last sprinkling with a black powder. This filling u may, however, be completely executed witli black powder or with colored particles. transparent varnish 11, which, as also the itchv matter which retains the grains.

should have an index of refraction as near as.

ossible to that of the colored particles in order that the light may pass through the screen-coating without being diflused. The screen-coating thus obtained is composed of a large number of small elements of difi'erent colors, which are distributed more regularly in'proportion as the mixture of the colored The whole is then covered with :1

grains 1s better effected. Above this coat mg the sensitive panchromatic coating f is spread by known means, and the plate thus obtained can be preserved as an ordinary late until the moment of use. When one of these lates is e osed, the back turned toward't-he object g ass, the luminous rays traverse the screen-coating before reaching the sensitive coating. It will be understood that a ray of any color cannot ,traverse the screen-coating except in the parts color and that it will be more or less arrested by the articles which do not contain this color or w 'ch contain only a part of it. Thus an impression will 'be made upon every point of the sensitive layer f, the intensity of which will depend upon the composition of the pencil of rays wluch forms the picture in this point and upon thecolor of the particles tln'ough which it point-that is to say, t e impression made upon the sensitive layer will have thevmaxi mum intensity in those points where the pencil of rays his the same color like the particle through which itpasses, a weaker impression oints where the pencil es have only in part the impression whatever oints where the penbeing made in those of rays and the partlc same color, while no cil of rays and color at all. After development and fixing the silver reduced. in the sensitive coating will mask to different degrees the colored elements of the screen-coating and in such man ner that in viewing the plate by transmitted of like asses in the same i light these elements will form a picture the colors of which will be complementary to those of the light which they have received during the exposure.

To restore the normal order, it will sufiicc to invert the negative by any of the known methods, such as treatment with the permanganate or the bichromate of potash acidulated, &c., followed by a second development.

Having fully described our invention, What we claim, and desire to secure by Letters Patent, is

A sensitive photographic plate for color photography comprising a transparent backing plate or support, a layer of colored particles suitably held on said plate and composed of larger particles with smaller particles lying in the interstices between the larger particles, a layer of varnish covering the particles and a sensitive layer supported over said layer of varnish, substantially as described.

In testimony whereof we have signed our names to this specificationvin the presence of two subscribing witnesses.

AUGUSTE LUMIERE. LOUIS LUMIERE. Witnesses:

THos. N. BRowNE, GAsToN J EANNIAUX.

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