Litho Processing: Its Finest Hour

Litho developers are formulated to produce high contrast silver images for the graphic arts, but those compositional factors which provide best performance also cause developer instability and degradation. As the industry has progressed from tray to machine processing, this degradation has resulted in severe quality and control problems that cannot be prevented by simple replenishment. How developer composition can be maintained, however, by using two independent replenishers to compensate individually for film throughout and for time dependent losses is discussed. These improved replenishment systems coupled with more precise processor operation have attained litho processing's finest hour. It can now provide (when operated competently) the control demanded by critical direct screen and electronic scanning operations.