Color reflected color depends upon the viewing angle. Numerous scientists have carried out research in butterfly wings and beetle shells, including Isaac Newton and Robert Hooke. Since 1942, electron micrography has been used, advancing the development of products that exploit structural color, such as "photonic" cosmetics. Color Color (American English), or colour (Commonwealth English), is the characteristic of human visual perception described through color "categories", with names such as red, orange, yellow, green, blue, or purple. This perception of color derives from the stimulation of cone cells in the human eye by electromagnetic radiation in the visible spectrum. Color categories and
HKS (colour system) HKS (colour system) The HKS is a colour system which contains 120 spot colours and 3520 tones for coated and uncoated paper. HKS is an abbreviation of three German colour manufacturers: Hostmann-Steinberg Druckfarben, Kast + Ehinger Druckfarben, and H. Schmincke & Co. HKS colours, similar to Pantone colours, can be used in any kind of print publication to produce predictable colours. As in the Pantone colour system, there are HKS colours that cannot be reproduced using the CMYK colour space, like bright orange or certain tones of blue. The HKS colour system is based on the euroscale colourspace. It follows