US328431A - Thomas c - Google Patents

Description

(No Model.)

T. O. ROCHE.

PHOTOGBAPHIG SENSITIVE PAPER.

No. 328,431. Patented Oct. 13, 1885.

WITNESSES INVBNTOR A m 6ZJ2ZW BY mm ATTORNEYS.

PETE s. Phom-Ulhographar, wuhin mn. D. C.

NTTED STATES PATENT Trice.

THOMAS C. ROCHE, OF BROOKLYN, ASSIGNOR TO E. & H. T. ANTHONY 87 00., OF NEYV YORK, N. Y.

PHOTOGRAPH IC SENSITIVE PAPER.

SPECIFICATION forming part of Letters Patent No.328,431, dated October 13, 1885.

Application filed December 24,1884. Serial No. 151,119. (No model.)

T on whom it may concern.-

Be it known that I, THOMAS 0. Boone, of Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in Photographic Sensitive Papers, of which the following is a full, clear, and exact description.

Many efforts have heretofore been made to provide a ready way whereby paper could be 1 rendered practically available in general photographic operations as a substitute for glass, which is objectionable on account of its fragile nature, thickness, weight, and great expense. The use of paper as heretofore prepared for I 5 photographic purposes has been attended with difficulties, among which are the appearance of the grain of the paper in printing with paper negatives, and the lack of strength or contrast in the shadows of the picture. To increase the strength or contrast of the shadows, it has been common for the operator to touch up the backs of the paper negatives or prints with ink applied by hand-a work that requires time, skill, and expense, and is even then defective,owing to the difficulty of placing the strengtheningdnks in the proper position on the backs of the pictures. By my invention all these difficulties are overcome; and it consists in a photographic paper having both of its sides or surfaces rendered sensitive to light by coverings or films composed of any of the ordinary well-known emulsions of gelatine and silver. Upon a photographic paper thus prepared negative and positive pictures may be produced by the ordinary methods, and by reason of the presence of the sensitive materials or films upon both sides of the sheet of paper certain new and important qualities are imparted to the picture, as will be hereinafter set forth.

Referring to the accompanying drawings, which form a part of this specification, Figure 1 is a perspective view of a sheet of paper inclosed between two sensitive films in accord- 5 ance with my invention. Fig. 2 is an edge elevation of the same, showing the sensitive material on both sides of the paper.

A in the accompanying drawings represents the body of a sheet of photographic paper provided with two films of the within-described sensitive material B, which incase the sheet between them, as shown.

In carrying out my invention I make use, preferably, of the Rives or Saxe paper, wellknown in the trade; but any other suitable paper orflexible material through whichlight may act, and the surface of which is suited to receive the sensitized emulsion, will answer.

. For the coatihg of the paper any of the ordinary sensitive gelatino-argentic solutions may be employed, of which the following is mentioned as a single example: Fine gelatine three hundred grains; water, ten ounces; bromide of potassium, one hundred and forty. grains; nitrate of silver, two hundred grains. These ingredients are to be mixed, cooked, washed, and filtered, and treated with chromealumor tannin to render the mixture insoluble, all in the ordinary manner well-known to photographers, further description being therefore unnecessary. The emulsion having been duly prepared is placed in a suitable vessel and kept at a temperature of 120 to 130 Fahrenheit, and the paper is then immersed in the emulsion so that both sides will be thereby evenly covered; or the paper may be first coated on one side with the emulsion and then coated on the other side. After the paper is thus coated it is to be dried in the ordinary manner, and when dry it is ready for use. One of the practical results arising from the combination of the two gelatino bromide films with the paper is that prints made from negatives composed of such paper are free from the appearance of what is termed grain. The two gelatine films and the paper com bined have a modifying effect upon the light to such an extent and of such character that the grain of the paper no longer shows itself in the print.

My improved paper may be used in the camera for the production of negatives, or in printing-frames for positive pictures in the usual manner. Either side of the prepared After-the rpicture is-takeniit is {to badeqeloped onboth sides'of the sheetby the-appli cation thereto of any of the well-known developing agents suitable for emulsion-pictu res. I at present prefer what is known asthe ferrousoxalate developer. The developer ,is,

as stated, to be applied to bothsidesio the emulsion-covered paper, the effect of'w'hichis the positive prints made 'from my paper-will be :free from all appearance of grain, and, if desired, the paper may-be'renderedadditionally transparent by treating the paper negative with wax, oil, or other suitable-material in the ordinary manner.

In furtherindicationof the state of theart, I'will add thatthe common wetcollodion :film 1 l ers-been. applied to both sides of glass plates; also that photographic paper has been made from pulp saturated with sensitizing-salts, and

that paper sheets have been coated on one side with the gelatino-argentic solution heretoforeimentioned; but in none of thesecases has the desired perfection of result been at- "tained-as'by my invention.

Having thus described my invention, I claim .anddesire to secure byLetters Patent 1. As an improved article of manufacture, a prepared sensitive photographic paper or other flexible support, made as herein described, with two separate sensitive faces of gelatine-silver emulsion, as set forth.

2. In photographic papers,the combination, with the body of the paper A, of the two separate films B of gelatine-silver emulsion, substantiallyas and for-the purpose herein set forth".

'3. A photographic sensitive paper, constructed withthe-body of the paper A 'inclosed between two sensitive films, B, of gelatine-silver emulsion, substantially as described.

'4. In a photographic paper, two separate sensitive films of gelatine-silveremulsion supported andcarriedupon a single sheetof pa per, :as -herein shown and described.

. THOS. O. ROCHE. Witnesses: :O.:-SEDewIcK,

EDWARD M. IGLARK.

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