Abstract: An electrophotographic recording material comprising a photoconductive layer incorporating photoconductive zinc oxide in the presence of a compound within the scope of the following general formula:R--SHwherein: R represents (1) an unsubstituted aliphatic hydrocarbon group containing at least 5 carbon atoms or (2) an aliphatic hydrocarbon group substituted with a --COOQ group wherein Q is an organometallic group or an aliphatic hydrocarbon group, containing at least 5 carbon atoms, or (3) an aliphatic hydrocarbon group substituted with a --COOH group and containing at least two methylene groups between the --COOH group and the --SH group, and said general formula including the modification wherein the hydrogen atom of the --SH group is substituted to form an organometal mercaptide.The above compound improves the charge retention of the photoconductive layer, i.e. lowers its dark-decay, under conditions of high relative humidity.

Abstract: An X-ray image intensifying screen, which includes in a binder layer rare-earth oxyhalide phosphor particles that are in contact or admixed with an inorganic or organic substance or mixture of substances bringing about that the fluorescence power of said oxyhalide phosphor particles is less prone to be reduced by moisture, said substance being a non-phosphor substance or a phosphor substance other than calcium tungstate and producing hydroxyl ions when put in water, wherein the hydroxyl ion production power of said substance is such that when putting said substance in water at 25.degree. C. in an amount of 0.1 equivalent per liter a pH of at least 8.0 is obtained and the solubility in water of said substance is such that at least 0.05 g of said substance is soluble in 100 ml of water at 20.degree. C.

Abstract: X-ray image intensifying screen including at least one fluorescent layer comprising phosphor particles dispersed in a binder and on top of such layer a protective layer containing a crosslinked polymer mass obtained by an acid-catalyzed reaction of a polymer or mixture of polymers containing reactive hydrogen atoms and a crosslinking agent, the crosslinking agent being an organic compound containing a plurality of etherified N-methylol groups.

Abstract: An X-ray image intensifying screen is described comprising halide-containing phosphor particles. In order to improve the stability to moisture and thus to protect against loss of fluorescence power the phosphor particles are admixed with, combined with or have reacted with one or more organic substances that are capable of reacting with hydrogen chloride and/or labile halogen. The stability is further improved by admixture of nonhygroscopic halide-free phosphor particles in such a ratio that the ratio of the intensification factor of said screen with respect to the intensification factor of said screen but containing no such halide-free phosphor particles is not smaller than 1:4.

Abstract: An X-ray image intensifying screen comprising (1) a layer (which may be a supported layer or a self-supporting layer) containing fluorescent light-emitting phosphor particles including one or more rare-earth metal compounds and (2) a light-diffusing layer or sheet, which contains numerous discrete light-scattering volumes of a substance or substances distributed at random in a binder medium or partially embedded therein, such volumes having a mean size not larger than 20 .mu.m, said layer or sheet being located so that fluorescent light of said phosphor particles can penetrate therethrough to the outside of said screen.

Abstract: A composition of matter such as an X-ray image intensifying screen which includes halide-containing phosphor particles which are admixed or combined with or have reacted with at least one metal-organic substance such that the fluorescence power of said phosphor particles is less liable to be adversely affected by moisture.