Tone and Color Control in Reproduction Processes.

A theoretical system is discussed for accomplishing: 1. Reproducibility or control, i.e., reduction of variability and accurate prediction of tone values. 2. Modification, i.e., willful introduction of variation to compensate for poor copy such as dark, contrasty, flat, or light originals. Current methods for accomplishing reproducibility and control are reviewed with emphasis given to estimation of tone values on halftones and plates, and prediction of final tone value. Methods for improving reproducibility are discussed. Instruments and techniques for improving reproducibility at Rochester Institute of Technology are reviewed. Illustrations are presented along with discussion of RlT's experience with the auto matic separation printer, the Ink Distribution Meter, and statistical quality control. An example of a tone control experiment is given, and samples of the result are shown. Application of control techniques to a system of three-color reproduction is discussed, and illustrations of control charts are presented.