US1939213A - Photographic film - Google Patents

Description

Patented Dec. 12, 1933 UNITED STATES PATENT OFFICE PHOTOGRAPHIC FILM Edwin Ernest Jelley, Harrow, England, assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New York No Drawing. Application November 9, 1931, Serial No. 574,047, and in Great Britain August 4, 1931 Claims. (Cl. 95-8) This invention relates to photographic films and may be added may be varied within wide limits plates and more particularly to film which-at the depending upon the degree of the matte effect that option of the user will when finished be either is desired. In general I have found that 1 percent matte or clear. by volume of the gelatin solution that which would 5 Numerous methods of making matte film have result in about percent by volume of the dried 60 been suggested but in all'of them the film furgelatin to be satisfactory. nished by the manufacturer was either perma- In the process of the fi the Organic Salt nently clear or permanently matte. such as calcium benzoate is transformed in an or:

The present invention provides a photographic dinary alkaline developer containing soluble alfilm or plate (both of which are hereinafter inkaline carbonate and sulfite into calcium carbon- 5 cluded for convenience in the expression film) ate and sulfite which remains in suspension in the to which a matte appearance may be imparted layer, giving the layer a matte or opalescent apor not, at will, during the treatment to which the pearance. On placing this film in an ordinary film is subjected after exposure. For this purfixing bath comprising sodium thiosulfate and bipose, the matte appearance is produced by resulfite the opalescence will disappear and a clear 7 action between a substance or substances incorfinished film will result. porated in the film and one or more ingredients If a matte surface is desired, the best results of a bath or baths used in the after-treatment, are obtained when the film is fixed in such an such as the developing or fixing bath. acid fixing bath containing anions of oxalic acid,

In the preferred form of the invention, the film preferably introduced in the form of an alkali ox- 7 contains a soluble salt of an alkaline earth metal, alate or ammonium oxalate. In such a fixing preferably calcium. Such salt is preferably inbath, calcium originally present in the film is corporated in a gelatine layer applied to the back converted into crystals of calcium oxalate having of the film, but incorporation of the salt, or of a a diameter varying from about In to 10 and propart of it, in the emulsion layer is not excluded; ducing a matte surface which is easily marked in the case of films coated on both sides with senby an H or HB retouching pencil. A suitable sitive emulsion, such as films intended for X-ray acid fixing bath is one containing about 1 perphotography, the salt may be incorporated in cent. of ammonium oxalate. either or both of the sensitive layers. The film may, if desired, be submitted to a 30 In the case of flexible film this backing layer solution of the oxalate of an alkali after the dewould then prevent curling. It would also give veloping bath and before the fixing bath with a matte appearance for inspection of the photosimilar results. graph and would have a rough surface for pur- It is also possible to include an oxalate in the poses of retouching or for working up the photodeveloper but I do not find this so satisfactory 35 graph. It could also be a carrier for a temporary for retouching purposes since the crystals thus anti-halation dye. It could also in the case of formed are extremely small. The opalescent apmotion picture film constitute an anti-static layer. pearance is, however, secured. A further modi- The salts may also be incorporated in a layer fication of the invention would comprise the between the emulsion and the support or above forming or inclusion of calcium carbonate in the 40 the emulsion. film before exposure and development. In this In the preferred form of the invention a solucaseit would remain unchanged by the ordinary ble salt of an alkaline earth metal, preferably caldeveloping bath but would be removed in the cium, is used. The backing layer is of a gelatin fixing bath or would be fixed in position by an and may be prepared by adding the salt dissolved oxalate bath before or combined with the fixing 5 in hot water to a 15 percent gelatin solution and bath. A further advantage in the presence of then adding water to bring the gelatin content calcium oxalate is that, if desired, it may be reto 10 percent. The following calcium organic moved by treating the photograph with dilute salts have been found particularly successful: hydrochloric acid, leaving the film clear and calcium benzoate; calcium salicylate; calcium transparent.

50 glycerophosphate; calcium lactate; calcium for- I contemplate as included within my invenmate, and calcium acetate. In general I have tions all such modifications and equivalents as found that any calcium organic salt having a fall within the terms of the appended claims. moderate solubility to be satisfactory. By this Having thus described my invention what I I mean of more than 1 percent and less than say claim as new and desire to secure by Letters 5 30 percent in water. The amount of this that Patent of the United States is:

1. A sensitive photographic element comprising a support with a colloid layer thereon, there being in the colloid layer a calcium organic salt having a solubility in water greater than 1 percent and less than 30 percent.

2. A sensitive photographic element comprising a support with a permanent colloid layer thereon, there being in the colloid layer a calcium organic salt having a solubility in water greater than 1 percent and less than 30 percent, and having the following properties (a) that the salt and the transformation products thereof formed in an ordinary developing bath remain in position therein (b) that the salt and transformation products thereof formed in an ordinary developing bath are soluble in an ordinary fixing bath, and (c) that the salt and the transformtion products thereof formed in an ordinary developing bath are transformable into crystalline particles insoluble in an ordinary fixing bath and which render the element matte.

3. A sensitive photographic element comprising a support with a permanent colloid layer thereon, containing calcium benzoate.

4. A photographic element comprising a sup-. port, a sensitized layer on one surface and a permanent colloid layer on the other surface containing calcium benzoate.

5. A photographic element comprising a support, a sensitive colloid layer and a second colloid layer containing a calcium organic salt having a solubility in water greater than 1 per cent and less than 30 per cent.

EDWIN ERNEST JELLEY.