Abstract: In the apparatus for applying a polymer film to a support as the film and support pass between a heating roller and a pressure roller the heating roller is provided with a freely movable electrical contact comprised of a disk extending into a pool of mercury at one end of the heating roller to accommodate longitudinal heat expansion of the roller to prevent radial variations in the heating element with consequent variations in heating patterns. The supply reel for the polymer film is provided with a spring bias friction brake having a readily disconnectable coupling with the supply reel to facilitate reel changing.

Abstract: The claimed reproduction procedure avoids the use of as many masks as there are degrees of shading for each primary color.For each primary color, only a single mask capable of being stripped and not painted in gouache is used. This mask serves as the mask assignable to the most densely shaded areas, and then upon stripping, as each of the masks assignable to the less densely shaded areas and so on to the weakest density. The mask acts as a photomask for a film which is underexposed for each degree of shading desired bymeans of a single screen.The invention is applicable to the reproduction of all documents using a number of shades of color.