<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (May 2017) (Learn how and when to remove this template message) </Td> </Tr> <P> The CMYK color model (process color, four color) is a subtractive color model, used in color printing, and is also used to describe the printing process itself . CMYK refers to the four inks used in some color printing: cyan, magenta, yellow, and key (black). </P> <P> The reason for black ink being referred to as key is because in four - color printing, cyan, magenta, and yellow printing plates are carefully keyed, or aligned, with the key of the black key plate . Some sources suggest that the "K" in CMYK comes from the last letter in "black" and was chosen because B already means blue . However, some people disagree with this because there is no blue in the primary CMYK colors; it is made with cyan and magenta . Some sources claim this explanation, although useful as a mnemonic, is incorrect, that K comes only from "Key" because black is often used as outline and printed first . It is more common in modern printing for the black to be printed last in order to yield deeper, cleaner shadows and crisper blacks than the imperfect black created by the CMY combination when those colors are printed over the black . The CMYK model works by partially or entirely masking colors on a lighter, usually white, background . The ink reduces the light that would otherwise be reflected . Such a model is called subtractive because inks "subtract" the colors red, green and blue from white light . White light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow . </P>

How many colors of ink are used to print