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April 10, 1934. M. MARTINEZ 1,954,325 PHOTOGRAPHICALLY PRODUCED GELATIN RELIEF Original Filed Nov. 17, 1930 al a. a 23.533.2232) 33%22.3%5833 52S3 ÉY %22E.;3E38%&233.5 2%E&23333333333% NSN MM % N Patented Apr. 10, 1934 1,954,325 UNITED STATES PATENT OFFICE 1,954,325 PHOTOGRAPHICALLY PRODUCEO GE LATN RELEF . Michele Martinez, London, England Original application November 17, 1930, Serial No. 496,341. Divided and this application March 26, 1932, Serial No. 60,446 6 Claims. (C. 95-5.6) This application is a division of my applica With a coated layer made similar to Example 1 tion, Serial No. 496,341, filed November 17, 1930 will be of the order of three minutes to sunlight and relates to the product in the form of a relief or an arc lamp. After completing the exposure obtained by the process described in that appli the surface is exposed to moderate heat, as for 5 cation. For the sake of completeness, the de example, before or over an electric heater or 60 Scription of the material and of the process will electric hot plate or in an oven, all of the type be fully stated in this specification. For the common in household use. Another method of sensitive material, I have found useful composi applying heat and bringing out the relief is to tions containing a metal ion and the ions of pOur Over it a hot substance such as molten wax 0 organic acids of the type which permit reduction or metal of low melting point or by dipping in 65 of the metal upon treatment with light or other hot oil. As indicated in the examples, the heat effective reagent. Such a composition in a suit ing must be vigorous, that is, rather sudden, in able carrier such as gelatin or other colloid, may order to bring up the required relief, but over be coated in a layer, dried, exposed to an image heating must, of course, be avoided. A tempera 5 and heated with the result that the colloid layer ture range which I have found advantageous is 70 Swells, producing a marked relief at the exposed between 90 and 130° C. but do not limit myself points. - to this range. For instance, I have heated at a Among the salts found by me to be most suit temperature of 200 to 210 for a short time, of able for the introduction of the ions above de the order of 10 seconds, with the result that a 20 fined are following: ferric Salts Such as ferric high relief was quickly developed; but such high 75 ammonium citrate, ferric ammonium oxalate, temperatures should not be maintained for a ferric chloride, ferric sulphate, mercuric chloride materially longer period or the relief may be and mercuric sulphate, and other salts of heavy charred or blistered. If heated slowly, the relief metals; or light sensitive compounds of a heavy is not so great; and if heated very slowly, no 25 metal such as cobaltimine. useful relief may be obtained due probably to 80 As an acid constituent, I find useful any car the escape of the evolved gas without swelling boxylic acid soluble in the mixture, and particu the gelatin mass. In this case, much of this larly oxalic, citric, tartaric or lactic acid. To gas probably escapes through the support if of these, acid salts may be added, Such as Sodium paper. 30 acid phosphate. The second method is to prepare the image in 85 I Will now describe various formulae and pro the layer by chemical means and then heat as cedures but it is to be understood that, while before. To accomplish this I may take any pho certain of these are preferred, they are all men tomechanical printing surface, or another relief tioned as examples capable of wide variation. image, moisten the surface of this With a Sub stance which will reduce the metal salt in my go 35 Eacample 1 coating, press into contact the surface thus mois Water------------... and - un mo m an a wram wrv m a saw 100 cc, tened and the coated support, allow them to re Gelatin---------------------------- 40 grams. main in contact for a short time, separate them, Ferric ammonium citrate----------- 5 grams. dry the coating, and then develop the relief by 40 Oxalic acid------------------------ 3 grams. heating as before. Substances suitable for use 95 This mixture may be coated either by hand or with coatings containing ferric salts are for ex machine on any suitable or usual Support, such ample, Solutions of stannous Salts, such as stan as film support, paper, glass, linoleum or metal. nous chloride, and sulphites, such as sodium sul The coating is then dried. It is desirable that phite. With coatings containing mercuric salts, 45 the drying should be relatively fast, as this will solutions of stannous salts of sulphites may be loo produce a coating which is faster to light for the used, or a solution of ferrous Sulphate containing cases where the coating is light printed. potassium hydroxide. It will be best to leave the Having now prepared the surface which is to coating and the moistened image in contact for furnish the relief, I may proceed in one of two Some time to insure a sufficiently complete conver 50 ways. sion of the metal salts of the coating. After sep- 05 The more common method, satisfactory in most arating them, the coating is allowed to dry for a cases, is next to expose the gelatin Surface to short time and is then heated to bring out the re a light image. This may be done by exposing lief. to an image, as by contact printing under a posi Another Suitable formula for a coating is the 5 5 tive or negative. The length of exposure required following: O 2 1,954,325 Eacample 2 The surface of the relief is Smooth and SOme Water----------------------------- 100 cc. what glossy. Gelatin---------------------------- 40 grams Although the reactions and the mechanics in Ferric ammonium oxalate---------- 10 grams wolved in my invention are imperfectly under stood, research indicates and it is my belief that, Another embodiment in which I have intro under the influence of heat, carbon dioxide is duced certain improvements is shown in given off by one or more of the ingredients at the Eacample 3 exposed points, and causes a cellular structure in the mass. 0 Solution A. Water-------------------- 100 cc. I have found that it is particularly desirable Gelatin ------------------- 40 grams. that there be a high ratio of carboxylic content Ferric ammonium oxalate 8 to 12 grams. to ferric iron content. In Example 1, this ratio Ferric annonium citrate 2 to 3 grams. is 5.4; in Example 2, it is 3.0, and in Example 3 Sodium oxalate------------ 1.5 grams. it is 2.5 to 5.6. In general I consider the lower limit of this ratio to be about ...5 and preferably 9) Ammonium oxalate.------- 1 gram. it should be well above 1.5, as indicated in the Oxalic acid---------------- 1.5 to 5 grams. examples. Sodium acid phosphate---- 1 gram. The gelatin layer of the original material has This is dissolved heat. To this is then added the physical characteristics as to Solubility, dense 20 Solution B. ness and the like that are customary in any pho tographic gelatin layer containing non-harden Water-------------------- 100 cc. ing salts. When subjected to heat up to 200° C. Mercuric chloride-------- 9 to 10 grams. there is no important change in the physical or Ammonium chloride------- 0.25 to i gram. photosensitive characteristics of the layer if the 25 In this formula, it is not necessary to add Solu latter had not been exposed to light. 100 tion B as indicated but in my opinion a slightly Where the layer has been exposed to a strong better coating and relief for some purposes can illumination, however, it yields, upon heating, at be obtained with its use. One to 3 grams of borax exposed points throughout its mass a gas (carbon may be added to Solution. A to increase the hard dioxide) which, being expanded in situ by the 30 ness of the relief. If a precipitate forms when heat, transforms the mass of the layer into a 105 Solution B is poured into Solution A, a few drops cellular ol' foamlike structure. If the layer is of hydrochloric or nitric acid may be added. In very thin the gas escapes without causing this this formula more oxalic acid gives a higher but expansion and it is necessary, therefore, that the Coarser relief. The same is true of the Sodium layer be relatively thick in order to obtain a max 35 and the ammonium oxalates. The sodium phos imum relief effect. 110 phate may be omitted, but in my opinion it adds Similarly gas forming at or near the Surface slightly to the quality of the coating. of the layer escapes without expanding the Sur Coating is done at any temperature above the face portion and there is left thin skin which melting point of the solution. As previously helps to seal this gas in the deeper part of the 40 stated drying should be carried out in a darkened layer as it expands to produce the relief effect. 15 room and be moderately rapid, especially if the It Will be seen that the resultant relief varies paper is to be light printed. It should be thor in thickness of the foamlike or cellular portion Oughly dry when used.

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