Standardization in Halftone Reproduction.

For many years the research for halftone reproduction was a stepchild. Occasional attempts stagnated because of obscure ideas concerning the formation of halftone dots. This blockade was relieved only after the lith films were created. A unique research program brought up new advanced recognitions which led to definite conclusions in the proper use of glass screens. These experiences opened the door for final recognitions which brought up special negative and positive contact screens, which give perfect tone reproductions over the whole density range in negatives as well as in positives.