Human hair color account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blond/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several gene pairs control the light versus dark hair color in a cumulative effect. A person's genotype for a multifactorial trait can interact with the environment to produce varying phenotypes (see quantitative trait locus). Natural hair color can be brown, blond, black, red, or white; all natural hair colors including grey, white and lightest blond, are shades of brown. The Fischer–Saller scale, named after Eugen Fischer and , is
Color photography over-filled with materials. Suspended nanoparticles in the glass prevent U.V light from causing chemical reactions that change image colors. For this reason stained glass is being used to capture true color images of Mars for the 2019 ESA Mars rover mission. Color photography Color (or colour) photography is photography that uses media capable of reproducing colors. By contrast, black-and-white (monochrome) photography records only a single channel of luminance (brightness) and uses media capable only of showing shades of gray. In color photography, electronic sensors or light-sensitive chemicals record color information at the time of exposure. This is usually done by