Primary color overlaid partially absorbing materials on a reflecting or transparent surface. Each layer partially absorbs some wavelengths of light from the illumination spectrum while letting others pass through multiplicatively, resulting in a colored appearance. Overlapping layers of ink in printing mix subtractively over reflecting white paper in this way to generate photorealistic color images. The typical number of inks in such a printing process ranges from 3 to 6 (e.g., CMYK process, Pantone hexachrome). In general, using fewer inks as primaries results in more economical printing but using more may result in better color reproduction. Cyan, magenta, and yellow are good
Blue–green distinction in language different and common words: while ' refers to the color of arterial blood, ' is a red tending towards yellow or the color of clay. Italian distinguishes blue ('), green (') and grey ('). There are also common words for light blue (e.g. the color of the cloudless sky): ' and ', and other for darker shades, e.g. ', indigo. ', the English equivalent of azure, is usually considered a separate basic color rather than a shade of "blu" (similar to the distinction in English between red and pink). Some sources even go to the point of defining "blu" as