US171392A

US171392A - Improvement in carbon photographs

Info

Publication number: US171392A
Authority: US
Publication date: 1875-12-21
Anticipated expiration: 1892-12-21

Description

U ITE STATES PATENT OFFIoE.

CLAUDE LEON LAMBERT, OF PARIS, FRANCE.

IMPROVEMENT IN CARBON PHOTOGRAPHS.

Specification forming part of Letters Patent No. 171,392. dated December 21, 1875 application filed I January 4, 1875. i

To all whom it may concern:

Be it known that I, CLAUDE LEON LAM- BERT, of Paris, France,'photographer, have invented Improvements in Producing Carbon Photographs; and I do hereby declare that the following is a full, clear, and exact description of the same. I

My invention is an improvement in process for producing carbon photographs or sun-pictures, produced in salts of chromiumor othboth together-glass and paper-and subject it to slight pressure for a few minutes, after which I immerse in warm water, and develop the positive print, which, according to the length of exposure, will make either a transparency or a picture seen by reflected light. It is upon this latter feature (the picture seen by reflected light) that the invention is based.

The positive picture having been thus developed, I then only have to immerse it in a bath containing from ten to fifteen per cent. of gelatine in solution, and to apply the card upon which the photograph is to be mounted,and which is also passed through this bath. The picture is then allowed to dry completely, and the image is then detached, and remainsas brilliant and glossy as the glass with which it was in contact. This brilliancy is not produced by a layer of gelatine, but by the image itself,

which is completely insoluble, and will, consequently, bear considerable friction, and'may even be wetted without affecting its appearance or durability.

By the above process I obtain an image which is, in fact, unalterable, and which is itselfpreserved by an almost unattackable body, (insoluble bichromated gelatine,) t. 6., the picture itself, and which is obtained in its true aspectthat is to say, non-reversed. Thus, in practice, it will not be necessary to have two poses to produce apendant-that isto say,

two portraits ofpersons face to face. i

The gradual strengthening which I apply to the salts of chromium consists ofla solution of eleven ounces(three hundred grams) of water, one drop of liquid ammonia, and fifteen grains (1 gram) of sugar, in addition to which is added, according to the desired intensity of the negative, a few drops of saturated solution of permanganate of potassa. The negative obtained from a transparent positive is then placed in a bath containing the above solution, and, if it is desired to obtain still greater intensity, some more saturated permanganate of potassa is added. The negative, thus strengthened,

will produce prints of thesame quality as wouldthe original negative. In this manner, also, transparent positives may be intensified, in order to impart greater brilliancy to the negativ'eto be obtained therefrom.

To obtain prints in salts of chromium on ordinary albnmenized paper, with borders in a scale of difi'erent tints, which contrast with that of the picture, I take ordinary albumenized, paper of any quality,and expose it to light after sensitizing; then place it in the press, taking care to preserve a blank forithe picture, with a black or yellow mask, and in this manner obtain an impression from a negative of any ornamental border, with a blank space reserved for thepicture. Ithen precipitate it with hyposulphite, and fix as in ordinary cases, and, if necessary, apply it to my oval or square photographs. I thus obtain tints which harmonize perfectly-one for the picture, and the other for the border.

I'claim v 1. A compound consisting of eleven ounces of water, fifteen grains of sugar, one drop of liquid ammonia, and a few drops of permanganate of potassa, to form a bath in which a negative obtained from atransparent posi-,

tive may be immersed, and thus intensified.

2. The process 'of obtaining double-tinted prints in salts of chromium and on ordinary albumenized paper, by placing the sensitized paper in a press, the blank for the picture he I I ing covered with a black or yellow mask, and

the whole being then precipitated by hyposulphite, as described.

CLAUDE Leon LAMBERT.

Witnesses:

GHARLES Dnsnos, ROBT. M. HooPEn.

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