UCR , under color removal

UCR, under color removal (In French ajout de sous-couleurs) modified chromatic composition in which the CMY components (tertiary colors) jointly involved in the shadow areas of the image (three-quarter to full tones) are replaced by a “short black”. The purpose is the reduction of the total ink coverage to significantly less than 400% to prevent drying and wet-on-wet ink trapping problems. When this reduction is extended to all areas of the three-color gray, this is gray component replacement (GCR) with a “long black”. There is no clear-cut transition to GCR: slight, medium and strong UCR with the maximum GCR, characterized by the increasing “length” of the definition black, going as far as the possible elimination of one of the process colors if it only makes a contribution near the gray axis. Today, optimum UCR and GCR settings are also anchored in high-quality ICC printing condition profiles and DeviceLink profiles like those made freely available by basICColor, for example, at www.colormanagement.org.