How Useful are Plate Scanners in Preadjusting Inking?

For the past two to three years plate scanners were in use on sheet fed presses. To what extent have original expectations been met? 1. How close do preadjustment and final inking adjustment match? What experiences have been gathered by printing plants? 2. Which influences on the part of the printing plate have a negative effect on the accuracy of measurement? What are the effects of uneven brightness of the printing plate and uneven coloration of the sensitive coating? Is the running direction of a printing plate of importance? The use of reference measurements to offset deficiencies of the plate. 3. In what way does the depth of field influence the accuracy of measurement? Measurement of diffuse reflection or direct reflection measurement? 4. The future of the plate scanner.