Results of a Study on Offset Collotype.

Continuous-tone printing as exemplified by the Collotype process is briefly explained together with a short history of its background both in this country and in Europe. Developments are brought up to date with the introduction in America of the Direct Rotary Press about 1930 and early attempts to print the Collotype plate by offset. Although the principles of Collotype have been applied to the Offset press, a new type of plate has been derived specifically for the purpose. The disadvantages of Collotype have been largely circumvented as a result. Long runs of high quality are now possible on grainless plates and without a water fountain on the press. The new plate was designed for the Army for the printing of aerial photos directly from the original aerial negatives without the intermediate steps of screening as in conventional offset. The continuous-tone image of the new plate shows excellent resolution of detail and tonal graduation on a par with Collotype.