Some Significant Aspects of Multicolor Wet Proofing.

The proofing of multicolor printing plates for any of the major printing processes is intended to serve two functions: (1) Advise the platemaker of the results from his platemaking efforts, and the customer of the degree to which the plates represent the copy submitted and (2) Serve as a guide to the printer, representing the results attainable under production printing conditions. Traditionally, the color-bar inserted into the proof press form and printed at the same time as the plates being proof printed, has served as a control guide. Recently, the addition of overprinted areas has further aided in visual and densitometric checking of ink film deposits for uniformity of film thickness. The increase in number of short-run color inserts and the use of cross-over color forms not having color control capability have made the application of ink density control more important than ever. Examination of multicolor proofs for film thickness and overprinting consistency have revealed a serious weakness in the multicolor printing system. The significance of the weakness and the necessity and tentative methods for improvement are described.