CMYK: 100, 100, 100, 100
Registration Black is a black colour used by combining all inks (100% coverage of cyan, magenta, yellow and black ink). This combination of so much ink causes issues in printing – such as drying, ghosting.
Registration black is represented by this icon in the swatches pallet in most design applications. Registration black is used for printers marks, but should not be used in your design.
Designs that use registration black will be rejected and sent a file error message.