PSO in the print shop
On the printing machine, the color is measured with the assistance of a spectral photo meter on the color measuring panel of the printing sheet. For primary colors (CMYK), the PSO stipulates LAB values for the relevant  paper type (RGB spectrums) the printer will have to achieve within certain tolerances (Delta E-values = color tolerances).

The tone value gain for different types of paper that must be attained is also stipulated. If all parameters are within the defined tolerances, the best match between proof and printing result will be attained. During production, the printer will have to make sure that the primary colors do not exceed a maximum deviation of Delta E ‹ 2.5.

Certificate
FOGRA, a German organization or UGRA from Switzerland audit  Evers-Druck for compliance with the above mentioned criteria. Provided the respective operations meet and fulfill said criteria, they are issued a  2-year certificate to that effect. After this 2-year period, another audit will have to be performed and the certificate will be extended by another 2 years.

This procedure ensures that the printing companies will uphold  compliance with the prescribed quality criteria at all times. During the auditing process, the quality is defined on the basis of measuring technical and visual procedures and inspected on site at the companies submitting to the audit. As a result, all participating companies are in a position to document to their customers the autonomously and neutrally certified production quality of their print products.

Of about 11,500 sheet offset printing businesses in Germany only around 150 are currently certified. This shows that receiving this certificate is not an easy feat for printing businesses. Evers-Druck is a PSO certified company.