1. A method for producing a record of retrievable information: providing a layer which comprises an imaging material in the form of a tetrahalide of tellurium in which the halide is at least one member selected from the group consisting of chlorine and bromine, said imaging material having one detectable characteristic and which is capable of undergoing a chemical change in response to the application of energy to produce a material of different chemical character having another detectable characteristic, said imaging material being dissolved or dispersed in a polymeric matrix material, the step of applying imaging particle or wave radiation to at least a certain portion of said layer to bring about the chemical change in said imaging material in said certain portion of said layer to produce said material of different chemical character and to record the desired information in said layer.