Color model or "CMYK" color space. The cyan ink absorbs red light but transmits green and blue, the magenta ink absorbs green light but transmits red and blue, and the yellow ink absorbs blue light but transmits red and green. The white substrate reflects the transmitted light back to the viewer. Because in practice the CMY inks suitable for printing also reflect a little bit of color, making a deep and neutral black impossible, the K (black ink) component, usually printed last, is needed to compensate for their deficiencies. Use of a separate black ink is also economically driven when a lot
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