Process Color Separations
All process-color separations use Cyan, Magenta, Yellow, and Black to create the colors in an image. These translucent colors blend on-press to create the myriad colors of an image. Process color separations can be made by converting a file to the CMYK mode using Adobe Photoshop®. CMYK inks are transparent and must be backed with white or used on a white background for color fidelity.
Even though most colors in an image will reproduce satisfactorily, to achieve very good results usually require more then just the 4 basic CMYK colors. Adding a highlight white increases contrast and some colors as deep-saturated orange and greens simply do not work well without enhancement. Additional add-on colors may be required for spot color matching or out of gamut colors.