Abstract: A hologon and its method of manufacture are described. Adjacent facets of the hologon are overlapped so that the diffraction effects created by boundaries of the mask which defines the extent of the interference pattern, which is a precursor of the diffraction grating, are overlapped, thereby increasing the duty cycle.

Abstract: A method and apparatus for admixing liquid with concentrated, shear-thinable stiff pastes of photographic processing compositions to form photographic processing solutions, in which the pastes are thinned by shear forces and contacted with the diluting liquid under turbulent mixing conditions to dissolve the concentrate in the liquid and thereby form the solution. The paste, which does not flow and resists deformation under conditions of low shear, is displaced through an orifice where conditions of high shear render it free flowing and form a stream. One or more liquid jets are directed at the stream with sufficient force to disperse the concentrate and bring about intimate contact between the liquid and the composition under turbulent mixing conditions. A static mixer then completes the dissolution of the chemicals in the liquid.