GB1394664A - Reproduction of photographic images - Google Patents

Abstract

1394664 Autoradiography AUSTRALIAN ATOMIC ENERGY COMMISSION 29 July 1969 [1 Aug 1968 16 May 1969] 38100/69 Heading G2X A photographic image is reproduced by treatment so as to induce radio-activity in the image material and then forming an autoradiograph from the image so treated. Prints of varying density and contrast may be obtained from underexposed negatives. Radio-activity may be induced (a) by irradiation with sub-atomic particles, e.g. thermal neutrons, or high energy gamma rays; (b) by chemical reaction of the image material with radio-active elements or their compounds; or (c) by treating image silver material with a solution containing a radio-active silver isotope. The autoradiograph is prepared by pressing the treated emulsion against an unexposed emulsion in a light-tight container. A pre-treatment with a photographic reducer may be given to remove background fog; silver sulphide fog may be cleared with a solution of KCN containing hydroquinone, a solution of thiourea, or a solution of thiogly- collic acid. In examples (1) the silver image is converted to radio-active silver sulphide, after an optional conversion to silver bromide; (2) polonium-210 is deposited from solution on to the silver image; (3) the negative is treated with a solution containing Ag-110m, Na 2 CO 3 , potassium ferricyanide, and KBr; (4) the silver image is converted to inactive AgI and then exposed to thermal neutrons to form I-128; (5) the silver image is toned with a mixture of uranyl nitrate, potassium ferricyanide and acetic acid, and irradiated with thermal neutrons while forming the print.