Grey Balance Colorimetry of the Automatically Guided Printing

Apart from visual control, it is possible to controll the ink on a print by means of auxilliary instruments - densitometer, colorimeter and spectral photometer.<br />One of the problems in offset printing reproduction is the inconstancy of theink flow and ink consumption during the run printing. This problem appears because of the change of ink viscosity, the change of ink temperature, the change of fountain solution quantity in ink, the change of printing speed etc.<br />This article shows the measurements of the chromatic values performed by spectral photometer on the control - signal strip from the very beginning of the run printing till 20000th print. Gray balance (CMY) by means of CIE L*a*b* system has been investigated. Densitometric values of the solid area, the growth of the screen values and doubling-shear have been determined. The results of the spectrophotometric measurements of gray balance and the densitometric measurements of the solid tint have been analyzed