A densitometric method of monitoring color variation during four-color offset lithographic press runs is proposed. Once an \u27OK\u27 press sheet has been approved for the run, a standard color reference is established with which successive sheet pulls can be compared. In order to develop an accurate and repeatable system for monitoring and controlling color variation, densitometric analysis of three color overprinted tints can be utilized. In relation to the OK sheet, changes in the three-filter density readings measured at specific points across successive press sheets, indicate the visual change in color hue and strength that occurs during the press run. This work suggests that offset printers could use the following color control technique: zero the densitometer on a seventy percent overprint control point or dark neutral image area of the OK sheet and compare the difference in density of the same point of any sample sheet. The difference will indicate the change in the amount of red, green and blue light being reflected from that point in the sample relative to the OK sheet and suggest the corrective action necessary to control color variability during the press run
