Abstract: A method of producing a disc having at least one substrate and at least one information layer on the substrate, the method includes bringing the substrate in parallel relationship with a stamper having a negative of the information layer to be formed on the substrate. A gap is located between the substrate and the stamper. A lacquer is injected into the gap between the substrate and the stamper. At least the stamper is rotated, moving the substrate and the stamper towards each other, thereby reducing the gap. The layer of lacquer formed between the substrate and the stamper is cured, and the stamper is removed, leaving the layer of cured lacquer with the information layer formed therein on substrate. Before bringing the substrate in parallel relationship with the stamper, the substrate is provided with a first information layer and a semi-reflective layer located thereon, whereby the layer of lacquer is formed onto the semi-reflective layer.

Abstract: Electrophotographic copying by use of a machine in which a charge image is developed by the application of electrically conductive marking (toner) particles can be carried out so as to produce well imaged copies of low-contrast originals that contain weak image information by effecting the copying under conditions which cause the charge image to be developed with a grayish background of sparsely attracted particles and, during the developement, applying between an electrode of the developing device and the photoconductive element an a.c. voltage having a frequency of between 1 and 7 kHz and an amplitude of at least 50 volts, thereby rendering the background homogeneous in tone. In positive working processes, illumination that underexposes the element is used and only the a.c. voltage need be applied in development. In negative working processes, illumination that over-exposes the element is used and in development the a.c. voltage is superimposed onto a d.c.