At Forever Live, I learned more about the Indigo printing process that Forever uses to produce photo books. Specifically, Forever uses a six color production process that produces improved color but is rarely used for consumer products. Six-color printing is generally used only for professional products since it costs approximately 50% more than four-color printing.
Light cyan and light magenta are the two additional inks used for six-color CcMmYK printing. With the expanded colors, printers rely less on grainy halftone dots to produce continuous tones. Light cyan and light magenta particularly evident in portraits, where light magenta improves skin tone reproduction, and in landscapes, where light cyan reduces the graininess of the blue sky. The next time you are looking at a six-color photo book or digital print, look carefully and you will see a difference.