Process Standards: Proof Check

Proof printing process standards require an internal reference file for calibration. For coated printing materials (paper types 1 and 2 and — with a future process standard — PS1), this internal reference is usually the FOGRA39L file describing the ISO12647-2 (or IT8.7/4) test chart.

The internal reference for uncoated printing materials is the FOGRA47L file.

The following check dialogs are feasible for proof process standards:

•Process standard

•Color values

•Printing Materials

Standard check for mini spot test strips

This proof check gives the color distance E and the maximum value for the following parameters:

•Average

•Maximum

•Primary colors (max): CMY total

•Maximum H primary colors: maximum hue deviation from E for primary colors

•Mean H gray: mean hue deviation from E for gray

Advanced evaluation of test charts

The advanced evaluation uses a test chart that has a much greater number of dots than the mini spots mentioned before. This chart is used for the adjustment process, i.e. for the determination and repeated correction of the proof profile. This check is much more thorough and offers additional checks because a much greater number of dots is measured:

•All dots of the test chart are included, the deviations of all test values from the internal reference file are calculated, and the resulting mean values must fall below a maximum threshold.

•Then, the saturated colored dots of the test chart determined by the standard are included. The mean deviations from the internal reference are calculated and must fall below a second thresh­old.

•Then, the deviations of all dots from the internal reference are calculated and sorted in ascend­ing order. The 95% limit of deviations must fall below a certain value.