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
Orange (colour) also widely worn by workers on highways and by cyclists to avoid being hit. A herbicide called Agent Orange was widely sprayed from aircraft by the Royal Air Force during the Malayan Emergency and the US Air Force during the Vietnam War to remove the forest and jungle cover beneath which enemy combatants were believed to be hiding, and to expose their supply routes. The chemical was not actually orange, but took its name from the colour of the steel drums in which it was stored. Agent Orange was toxic, and was later linked to birth defects and other health