Rich black is a combination of 40% cyan, 30% magenta, 30% yellow and 100% Key (black).Rich black is used for large black images or objects to ensure a nice deep solid black. 100% black on its own isn’t always enough to produce this so we add 40C, 30M and 30Y to boost the richness of the black. IMPORTANT: Rich black should NEVER be used on text or thin lines or objects. 100% of all 4 CMYK colours should never be used as well. A rich black can be created by creating a new spot colour in Indesign/Illustrator and setting the values to 40c, 30m, 30y, 100k