Improvements in or relating to photographic processes
Реферат: 270,386. Wade, H., (Wadsworth Watch Case Co.). Feb. 4, 1926. Plates and films; sensitive coatings, preparing. -A sensitive medium for photographic or photomechanical use is prepared by incorporating in selected sensitive portions of asphaltum which form the main base of the medium, a sensitizer which liberates a halogen on exposure to light, such as a metallic halide and a halogen-substituted hydrocarbon. The medium may be used in the production of screenless grained litho plates, monochrome or colour-record intaglio, relief, or halftone printing-plates, or for line engraving on zinc, copper, &c. It renders possible the production of printing-surfaces from continuous tone negatives without resource to aquatint grain, reticulation, screens &c. Exposure is effected under an arclamp in from one half to four minutes. In an .example, a coating is prepared containing asphaltum, solvent naphtha, benzine, and a sensitizer comprising ethyl methyl ketone, iodoform, solvent naphtha and ammonia, all in stated proportions, and is applied to a grained or smooth surface. A similar sensitizer including also lead triethyl iodide may alternatively be used. After exposure to an image by contact or projection, development is effected by rubbing with a mixture of oleic acid and white mineral oil to remove the unexposed portions of the layer, followed by rinsing with dilute ammonia and water. In a further example, the coating comprises hydriodic acid, iodoform, asphaltum, and a small quantity of ammonia which is added to stabilize the coating, but is preferably neutralized before exposure. Specification 203,285 is referred to.
Color transfer photographic processes and products with indole phthalein filter dyes
Номер патента: US4615966A. Автор: Cheryl P. Petersen,Alan L. Borror,Efthimios Chinoporos. Владелец: Polaroid Corp. Дата публикации: 1986-10-07.