Recent Developments in Glass Halftone Screen Design.

Factors which have contributed to a revival of interest in glass screens are rear case design problems in automatic platemakers which prevent the use of contact screens, requirements for exact exposure constants from one screen to another in high production shops, and the durability of the glass screen. Manufacturers have been prompted to develop new types of glass screens designed to extend their basic flexibility while overcoming some of their inherent difficulties such as long exposure, limited density range and restricted detail transfer. Four new glass screens are described: a glass magenta screen with variable density of lines (the Allton Gradar from Klimsch & Co.), Max Levy & Co.'s Halftone Grating, a kind of glass screen which has transparent rulings and performs the screening function by diffraction alone; a glass line screen for use in xerography: a glass lenticular screen for use in contact with the film plane - prototypes have been made.