In Cyan, magenta, yellow, and key (black) CMYK (or sometimes YMCK) is a subtractive color model used in color printing. This color model is based on mixing pigments of the following colors in order to make other colors: C=Cyan M=Magenta Y=Yellow K=Key (black). The mixture of ideal... CMYK printing, registration black refers to 100% coverage in each of the four process colors: cyan (C), magenta (M), yellow (Y), and Black is a color with several subtle differences in meaning. Color or light Black can be defined as the visual impression experienced in directions from which no visible light reaches the eye. (This makes a contrast with whiteness, the impression of any combination of colors of light that equally stimulates... black (K). It is a special purpose color, and as such is not generally used to print black text or In computing, a grayscale or greyscale digital image is an image in which the value of each pixel is a single sample. Displayed images of this sort are typically composed of shades of gray, varying from black at the weakest intensity to white at the strongest, though in principle the... grayscale graphics (but see rich black).

Instead, registration black is used for printing crop marks, or "registration marks". When proofs for each color were generated on separate pieces of film, use of registration black made crop marks visible on all channels, providing a useful reference for alignment. A thin line printed in registration black can also be used to check whether the printing plates are lined up.

External links

• Media Forge's FAQ on graphics and printing (http://www.mediaforge.com.au/faq.htm)