US1499844A - Process for producing copying foils - Google Patents

Description

Patented July 1, 1924.

EUGEN SEYFFERTH, OF BERLIN, GERMANY.

PROCESS FOR PRODUCING COPYING FOILS.

No Drawing.

T 0 all whom it may concern:

Be it known that I, EUGEN Snrrnnnrn, citizen of Germany, residing at 2 Panoramastn, Berlin, Germany, have invented a new and useful Improvement in the Processes for Producing Copying Foils; and I do hereby declare the following to be a full, clear, and exact description of the same.

This invention relates to an improved process for producing copying foils for photo-mechanical transfer purposes. It iswell known that hitherto the transfer for photo mechanical purposes, or photographic positives or negatives, on transparent paper, tracing paper and the like of letter press printing, illustrations of all kinds, music, and drawing or writing, was effected by copying the object upon a sensitive layer of chromate by itself, or applied to a lithographic stone, metal plate, or the like and then treating the thus obtained transfers according to the purpose for which they were intended.

The processes hitherto employed had many very serious defects. It is rather difficult to put together the design to be copied, Without cutting up the glass plates, and the difierent thickness of the glass causes trouble during the copying process.

It is, on the other hand, a matter of ex perience that the films of designspulled oif glass plates can be handled only with difficulty, and cannot easily be cut to the desired oval or other shape, because the films are very thin and are liable to become damaged, and have a tendency to curl or frizzle. Designs on tissue-paper are also rather unsatisfactory for photo-mechanical transfers, inasmuch as it is necessary to handle the ex tremely thin and easily torn tissue-paper very carefully, owing to its tendency to crease. Tissue-paper is furthermore unequally milky or cloudy and does not possess sufficient transparency. The insertion of printed pictures in places left vacant in the form also leads to unsatisfactory copies, owing to the double layer of paper interfering with the penetration of the light.

All these defects are effectively overcome Application filed November 14, 1921. Serial No. 515,117.

by the present invention, according to which transparent plates or films of cellon (acct ylcellulose), are employed in place of tissue or similar paper. In cases where the danger of fire exists, cellon (acetylcellulose) (so-called fire-proof or incombustible celluloid), is exclusively used. In the following description will be used, for the sake of brevity only, the term cellon, which must be understood to cover all similar plastic substances more or less suitable to serve as carrieils, bearers or foundation for copying foi s.

The parts of the cellon not printed upon, allow the light to pass through without obstructing it in any way, as transparent cellon is as transparent as the best glass and the time for exposure to the light therefore becomes constant. As the cellon, even in comparatively large pieces, is handy and strong, sheets once used can be washed and the printing ink removed, whereupon they can be used over and over again for the same purpose. Corrections or changes may also easily be made. As the cellon is very thin, superimposed layers do not cause any lack of clearness in the copies and the results obtained are most excellent.

It is well known that it is not easy to print upon cellon. It is therefore necessary to especially prepare the face of the plate destined to receive the impression. With this end in View the cellon plate is, prior to the printing, rubbed with amixture of glacial acetic acid and acetone, allowed to dry, and then the treated surfaces are printed on with entirely satisfactory results. Thin films of positive or negative photographs, screen photographs, line drawings and the like, drawn off glass plates may be applied to transparent cellon sheets, trimmed to the size of the space left vacant in the form and cemented or otherwise attached, and preferably at the corners. Foils attached in this manner may easily be removed and replaced by others, or removed after use and stored until again wanted.

What I claim as my invention, and desire to secure by United States Letters Patent is:

An improved process for the production trations on thin foils of cellon, for their 10 of copying foils of cellon, comprising, treatphotomechanical transfer purposes. ing the surface of plates of transparent cel- In testimony whereof I have signed my lon (acetyl-cellulose) with a mixture of glaname to this specification in the presence of 5 cial acetic acid and acetone, allowing the two subscribing witnesses.

plates to dry, whereby to effect equal recepi DR. EUGEN SEYFFERTH. tion of printing-ink by the thus treated Witnesses:

cellon, mechanically printing on the thus Dr. CONRAD CnMFERs,

prepared surface, and then applying illus- OTTO Morass.