A projecting screen for optical purposes which meets the stringent requirements for the reproduction of macroscopic as well as microscopic images in transmission operation. The object comprises providing a projection screen comprising several scattering media movable in relation to each other, by which projected images may be reproduced free of grain- and flickering- or scintillation effects, under simultaneous improvement of the resolution and the transmission qualities. The substance of the invention comprises a projecting screen in which two solid inorganic or organic media are movably assembled in relation to each other, of which one or both may be light-scattering because of surface roughness on one side, and a liquid flowing between these two means which may or may not have a scattering effect. This invention is of multiple use in the construction of scientific instruments.