GB650456A - Improvements in recording images by means of phosphors - Google Patents

Abstract

650,456. Delayed-action recording by means of phosphors. KODAK, Ltd. March 25, 1947, No. 8158. Convention date, March 26, 1946. Drawings to Specification. [Class 98 (ii)] [Also in Group XL (a)] A method of delayed-action recording of a long wavelength image comprises exciting uniformly with short wavelength radiation a layer of a phosphor which stores the exciting radiation and releases at least part of it when stimulated by long wavelength radiation as radiation of intermediate wavelengths, forming an image in the long wavelength radiation on the excited phosphor so as to exhaust it imagewise, and then placing the excited phosphor with its " exhaustion " image in printing relation to a photographic layer and stimulating the phosphor by illuminating it uniformly with long wavelength radiation so that the emitted radiation exposes the photographic layer. Alternatively, the image formed by the stimulated emission may be traced manually to give a permanent record. The long wavelength (infra-red) image may be projected on to the excited phosphor and the image formed by the light emitted by it when stimulated with infra-red is recorded by a photographic camera. Alternatively, the infra-red image may be " contact printed " on to the excited phosphor, if desired through the base of the phosphor as in " reflex " printing, and photographic contact prints taken from the image-wise exhausted phosphor by flooding it either through the photographic material or the phosphor with infra-red. If several prints are to be taken from a single excitation of the phosphor, the intensity of the flooding infrared is increased to keep the exposure time constant. Numerous examples of suitable phosphors are given in the Specification. Specifications 650,455, 650,458 and 650,459, [both in Group XL (a)], are referred to.