GB763797A - Improvements in dye transfer processes particularly for colour photography - Google Patents

Abstract

763,797. Imbibition transfer process for monochrome and multicolour photography. KODAK, Ltd. Jan. 21, 1955 [Jan. 21, 1954], No. 1941/55. Class 98(2) A silver image in a developed and fixed emulsion layer is converted to a silver halide image, dyed, with a basic dye in the presence of a water-soluble halide, washed to remove excess dye and halide, and pressed while still moist into contact with a moist mordanted receiving sheet in the presence of a water-soluble silver salt for transfer of the dye image. Thus dye is absorbed on the halide image in the presence of soluble halide but is released by the silver salt. Repeated transfer may be effected after washing the emulsion to remove soluble silver salt and re-dyeing and treating with soluble halide. The process is particularly adapted for preparation of subtractively coloured dye images from silver colour separation negatives, thus in Example 1 the negatives developed to a gamma of about 0.5, after normal fixing and washing are treated in ferricyanidepotassium iodide bleaching bath and washed, the red separation is treated in a solution comprising acetic acid, potassium iodide and Malachite green or Rhodaline Blue 6GA, washed in dilute acetic acid, and rolled in contact with a receiving layer comprising deashed gelatin incorporating the sodium salt of phosphotungstic acid as mordant, and which has been soaked in silver nitrate solution containing acetic acid; the receiving layer is then reconditioned with acid silver nitrate solution and printed similarly from the green and blue separations using Astraphloxine FF and Acriflavine respectively as dyes. In a second example a receiving sheet prepared by coating a solution contaning hydrolysed 5 - [4 - (2:4 - di - tert - amylphenoxy) - 3 - (2 - hydroxy - 3:5 - dichloro - 4 - methylphenylcarbamyl) phenylcarbamyl] - 1 : 3 - benzene di-sulphonyl chloride as mordant, saponin as spreading agent and mucochloric acid as hardening agent and gelatin, on cellulose acetate film base, is first conditioned in a hardening bath comprising sodium hexametaphosphate, sodium bisulphite, sodium carbonate, sodium sulphate, potassium bromide and formalin, and then in an acetic acid silver nitrate bath, and is rolled in contact with a silver image treated as described for the red separation of Example 1 to demonstrate the effectiveness of the dye transfer. Numerous basic dyes and water soluble halides for application to the silver image and mordants for the receiving sheet are described.