To minimize moiré, the Prinergy screening engine uses a software component called the geometry solver to slightly adjust the frequencies and angles of all colors. It is common to see a slightly different frequency for each color when measured in Kodak Copydot Toolkit software, and the geometry solver will stretch the frequency of the yellow up to 14% to minimize moiré. Although this increased stretching of the yellow is not an issue in offset printing, increasing the frequency of the yellow has a side effect of decreasing the size of the minimum dot value. It is possible that the yellow frequency stretch can create a minimum dot that will not develop reliably on plate. For this reason, there is a feature in Prinergy output process templates that allows you to turn off the yellow stretching function and output yellow at the nominal angle specified in the template.
Turning off yellow frequency stretch