US1305195A - Silvio cocanari - Google Patents

Description

S. COCANARI.

ANTIHALATION COMING FOR PHOTOGRAPHIC PLATES AND clNEMAToGRAPH FILMS. APPLICATION FILED APILZ. 1914.

l ,EGEL l 95 Patented May 27, 1919.

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SILVIO COCANARI, F VIEUX-DIEU, NEAR ANTWERP, BELGIUM.

ANTIHALATION COATING- FOR PHOTOGRAPHIC PLATES AND CIEMATOGRAPH-FILMS.

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Specification of Letters Patent.

Patented May 27, 319ML Application led April 2, 1914*. Serial No. 829,125.

To all whom it may concern Be it known that I, SILVIO CocANARI, technici an, a citizen lof the Kingdom of Italy, and

resident 0f Vieux-Dieu, near Antwerp, Belgium, have invented certain new and useful Improvements in Antihalation Coatings for Photographic Plates and Cinematograph- Films; and I do hereby declare the following to be a full, clear7 and exact description of the invention, such skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon,

`which form part of this specification.

The present invention relates to improvements in photographic plates and filmsan'd cinematograph films. The object is to avoid what is termed in photography as hala-tion. This phenomenon is due toluminous rays, that have passed through the sensitive coating, striking the back of the plate or the film and being refiected back from it at a certain angle on to the sensitive emulsion or coating.

The reflection of the luminous rays produces a white aureoleor halo around the images of objects that are too clear or too luminous. l

vUp to the present this objectionable feature has been overcome by covering the back of the plate, that is to say, the side opposite to the one coated with the sensitive emulsion, with a coating of red, yellow o-r black coloring matter. These colors have the property of absorbing the luminious actinic rays, and, consequently, they prevent the reflection of those rays and thus avoid the second impression ofthe image around the first one, that is to say, the formation of the halo on the photo-graphic alate. l The anti-halation coating which covers the back of the plates'is generally formed' of a gluey substance, soluble in water and in the baths used for developing the plates. VVith'it there is mixed a quantity of lamp black or other insoluble coloring material. Before proceeding to develop the plate, the coating must be washed off or removed, for, otherwise, it would be impossible to carry out the printing of positives by means of the negatives obtained with such plates, for

-the anti-halation coating would stop the passage of the actinic rays.

This known process is objectionable inl as will enable others' -film or plate, the support many ways. The presence of such a coating,I soluble and gluey, and consequently almost always hygroscopic, exercises an unfavorable infiuence on the preservation of the sensitive emulsion, or the coating adheres to the emulsion. This latter occurs especially with films.

Before de'veloping, the plates or films must l be washed very carefully, and this is a difficult procedure with strips of films of considerable length. Lastly,it very frequently happens that portions of the anti-halation coating adhere to the sensitive surface.

In the accompanying drawing which forms a part of the application:

Figure l is a section of a film in which the non-halation coating is disposed on the back O-f the film;

Fig. 2 is a similar view of a modified form showing the non-halation coating placed between the sensitized layer and the film support; and i Fig. 3 is a similar View of another modification wherein the non-halation substance is incorporated in the film support.

In Fig. l of the drawings there is illustrated a photographi-c or cinematographic 1 of which is provided on one side or surface with a layer 3 of sensitive emulsion and on its other side or surface with an indelible non-halation layer or coating 2. This non-halation coating2 according to the present invention violet non-halation coating is that it oersy no obstacle to the passage of red light which isA used in the developing room, and because of this fact the progress of development of the film can be readily observed. ,This feature is important as most non-halation coatings which are permanent are not transparent to red non-actinic light and they completely hide the image on the film and make development of the same very difficult. Furthermore, owing to the transparency of the violet coating it offers no obstacle to the passage of the luminious actinic rays for the printing of positives. It is thus unnecessary to remove the nonhalation coating 4 as shown in Fig. 3 of the drawing. In'

during the printing process, and obviously this is a lgreat improvement over the heretofore known non-halation lms or plates.

The non-halation coating 2 is generally spread on the back of the film 0r` plate support as illustrated in Fig. 1, but it can just as readily be'placed between the sensitized emulsion 3 and the support l as shown in Fig. Q, or the film support can be colored violet, o r inother words, the indelible coating can be incorporated in the lhn support elther case the result is the same, as the violet backing prevents the rays of light which pass through the sensitized emuls1on from being reflected back' upon' the same causing halation.

aving now particularly described and ascertained the nature of my said invention .and in what manner the same is to be performed, I declare that what I claim is:

1. A photographically sensitive element including a sensitized layer and an indqli'ble violet colored backing for said layer, said violet colorednbacking being of an intensity to prevent halation, but being transparent to actinic rays and also to non-actinic red comprising a transparentsupport having a photographically sensitive coating 0n one of its surfaces and havingan indelible violet colored layer located in the .rear of said sensitized coating, said' violet colored coating being of an intensity adapted toprevent halation, but being transparent to actinic rays and t0 non-actinic red light.

In testimony whereof I aliX my signature in presence of two witnesses.

n SILVIO COCANARI. Witnesses M. DEFVRIMONT, PAUL BART.

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