US1450479A - Photographic film with a carrier permeable to water - Google Patents

Description

Apr. 3,1923. 1,450,479

J. E. BRANDENBERGER PHOTOGRAPHIC FILM WITH A CARRIER PERMEABLE TO WATER Filed Mar. 7, 1921 Per meabj Rim. Permeafile Fzj/m.

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UNITED STATES PATENT OFFICE.

J'AQUES EDWIN BRANDENBERG-ER, OF PARIS, FRANCE, ASSIGNOR TO LA SOCIETE LA CELLOPHANE, SIEGE SOCIAL, F PARIS, FRANCE.

PHOTOGRAPHIC FILM WITH A CARRIER PERMEABLE TO WATER.

Application filed March 7,

To (all whomit may concern:

Be it known that I, JAQUES EDWIN BRAN- DnNnERoE-R, citizen of the Republic of Switzerland and resident of Paris, France (postoflice address 16 Rue du Louvre}, have invented new and useful Photographic Films with Carriers Permeable to VVate'r, which improvements are fully set forth in the following specification. v This invention relates to photographic films with a carrier that is permeable to water. I

Photographic films with a carrier permeable to water have been obtained by soaking under certain definite conditions, the permeable carriers, such as cellulose and other materials, in various baths with the object of forming the sensitive salt in the interior of the films. This salt therefore is 20 found, as one can imagine, concentrated in the vicinity of the two surfaces of the carrier, the concentration diminishing progressively towards the centre of the thickness of the carrier. From a photographic point of 5 view this double concentration of the sensitive salt on the surfaces may give rise to certain inconveniences such as insufiicient definition of the image.

The object of the present invention is a process which is applied to photographic films, with a carrier permeable to water, with the object of obtaining a single sensitive surface on the carrier; in other words to effect the concentration of the sensitive salt on only one surface of the carrier.

To obtain this result, one of the following two pirocesses may be used.

' 1. he permeable film, of whatever kind; .viscose for example, is thoroughly moistened 40 beforehand, the surplus water being then pressed out. After this, the carrier being still Wet, a photographic emulsion with a gelatine base is applied as a coating which is very uniformly distributed over the surface of the film and remains so during all the time which precedes coagulation.

2. The permeable carriers are passed through the first bath which serves to cause the film to swell up and impregnate it with one of the products intended to react subsequently. After this, and before passing the film through the second bath, it is doubled, that is to say, two films are laid one against the other, and passed for example between pressing rollers. Thus a 1921. Serial N0. 450,399.

double filmis obtained which is then submitted to the action of the final bath with the object of forming the sensitive salt in the interior of the film. After this operation the two films previously stuck together are separated and thus two films are obtained in which the sensitive salt is found to be concentrated on a single surface.

The single figure of the accompanying drawing is a fragmental sectional view, on a greatly enlarged scale, of a double film constructed as above described: l1 indicating the two permeable carriers or fihns, and 22 the layers or coatings of sensitive salt formed on their outer faces.

It is evident that instead of sticking the two films together between the first and second bath, they may be stuck together before or during their passage through the first bath.

This method of operating furnishes two films in every case; but evidently, at the expense of the output, each film could be fixed on a carrier, impervious to the baths,

for example on a fiat ,or cylindrical glass surface and afterwards separated therefrom, thus obtaining the same result as that mentioned above.

What I claim and desire to secure-by Letters Patent is 1. A method of manufacturing photographic films, comprising the steps of moistening a cellulosic carrier permeable to water with a liquid, expressing the surplus liquid from the carrier, and then subjecting one surface only of the carrier to the action of a different liquid to form a sensitive layer on said surface; substantially as described.

2. A method of manufacturing photographic films comprising the ste s of passing a cellulosic carrierpermeab e to water first through a solution of a salt which will cause the carrier to swell and become 1mpregnated with the salt, and then through a solution of a salt which will react With the first salt to produce a sensitive layer; doubling the carrier, so that two carriers are laid one against the other, prlor to the passage of the carrier through the second solution, thereby to form the sensitive layer on solely one surface of each carrier; and then separating the two carriers.

3. A .method of manufacturlng photographic films. comprising the steps of passin a cellulosic carrier permeable to Water through a solution of a salt which will cause the carrier to swell and become impregnated with the salt; doubling the carrier, so that two carriers are laid one against the other, before the passage of the carrier through said solution has been completed; passing the doubled carrier through a solution of a salt which will react with the first salt-to produce a sensitive layer on solely one surface of each carrier; and then separating the two carriers.

4. A method of manufacturing photographic films, comprising the steps of passing a cellulosic carrier permeable to water through a solution of a salt which will cause the carrier to swell and become impregnated with the salt; doubling the carrier, so

that two carriers are laid one against the In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

JAQUES EDWIN BRANDENBERGER. Witnesses:

GEORGES PASCAL CAmuEnr, GERMAINE MIGHIELS.

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