Patent GB-190122841-A (GB)
Title: A Process for Reproducing Pictures or the like.
Inventor: GROS OSCAR
Filed: 1901-11-12
Granted: 1903-02-12
Abstract: 22,841. Gros, O., and Ostwald, W. Nov. 12. Inkless printing by chemical reaction.-Relates to a process, for reproducing pictures &c., depending upon catalytic action. A picture is first formed of a catalysing-substance such as platinum, silver, metallic salts, oxides, &c., and this is used for reproduction of the picture on paper, metal plates, gelatine, or other carrier, by modifying or accelerating the reaction of chemical substances. The platinum or silver prints of the picture may be produced by the usual photographic processes or other suitable means, as, for example, by drawing with a saturated solution of potassium-platinum chloride, and converting this drawing into metallic platinum by means of a solution of potassiumferrous oxalate. A drawing for acting catalytically may also be made by drawing with a saturated solution of oxalic acid upon paper treated with a feebly-alkaline solution of potassium permanganate. The platinum &c. print is pressed close against paper or other surface covered or treated with substances the chemical reaction of which is accelerated or modified by the platinum &c., whereby a reproduction of the picture is obtained on the surface directly or by subsequent treatment or development with other chemicals. For example, paper impregnated with a solution containing from one to five per cent. of potassium bromate and from five to twenty-five per cent. pyrogallol, when pressed against a platinum original has the picture produced upon it by chemical reaction in the parts in contact with the platinum. Other substances may be used for treating the paper. A silver-bromide gelatine plate or paper which has been exposed to the action of light for a moment may be pressed against a platinum print impregnated with a saturated solution of potassium bromate, and a print obtained by developing the plate or paper in the usual manner. The platinum print may also be treated with a solution of a substance, such as hydrogen peroxide, which is more or less modified by the platinum of the design, and the print then pressed against paper &c. impregnated with a substance upon which the modified or not modified substance can act, so as to produce an image which can be developed. Several examples of the use of hydrogen peroxide in this manner are given in the Specification. Other catalysing-agents may be added to the sensitive substances, which agents are caused to act more rapidly in conjunction with the platinum &c. For etching metallic plates, substances are used which, at the places in contact with the platinum or catalysing-substance, produce a chemical action to etch the plate. For example, a platinum print impregnated with a solution of potassium chlorate in acetic acid is pressed against a polished copper plate. A printing-plate for printing with fatty colours may be obtained by pressing the platinum print, treated with hydrogen peroxide, against a gelatine plate, and then placing the plate in a concentrated solution of ammonium ferrous sulphate. An etching-resist may be obtained on a metal plate, by covering the plate with fish glue containing a chromate and pressing upon it the platinum print impregnated with hydrogen peroxide. The glue is made insoluble at the parts where the peroxide exists, and is further treated by the usual methods.