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In the 18th century, purple was a color worn by royalty, aristocrats and other wealthy people. Good-quality purple fabric was too expensive for ordinary people. The first cobalt violet, the intensely red-violet cobalt arsenate, was highly toxic. Although it persisted in some paint lines into the 20th century, it was displaced by less toxic ...
Impossible color. The human eye's red-to-green and blue-to-yellow values of each one-wavelength visible color [citation needed] Human color sensation is defined by the sensitivity curves (shown here normalized) of the three kinds of cone cells: respectively the short-, medium- and long-wavelength types. Impossible colors are colors that do not ...
In the 1730s, Carl Linnaeus in his introduction of systematic taxonomy recognized four main human subspecies, termed Americanus (Americans), Europaeus (Europeans), Asiaticus (Asians) and Afer (Africans). The physical appearance of each type is briefly described, including colour adjectives referring to skin and hair colour: rufus "red" and ...
Eye color. Eye color is a polygenic phenotypic trait determined by two factors: the pigmentation of the eye 's iris [1][2] and the frequency-dependence of the scattering of light by the turbid medium in the stroma of the iris. [3]: 9. In humans, the pigmentation of the iris varies from light brown to black, depending on the concentration of ...
Color psychology is the study of colors and hues as a determinant of human behavior. Color influences perceptions that are not obvious, such as the taste of food. Colors have qualities that can cause certain emotions in people. [1] How color influences individuals may differ depending on age, gender, and culture. [2]
Rhodopsin, also known as visual purple, is a protein encoded by the RHO gene [5] and a G-protein-coupled receptor (GPCR). It is the opsin of the rod cells in the retina and a light -sensitive receptor protein that triggers visual phototransduction in rods.
The color purple, as defined in the X11 color names in 1987, is brighter and bluer than the HTML/CSS web color purple shown above as purple (HTML/CSS color). This is one of the very few clashes between web and X11 colors. This color can be called X11 purple. Veronica prostrata, for which the color veronica is named.
Hematoxylin and eosin stain (or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. [1][2][3] It is the most widely used stain in medical diagnosis [1] and is often the gold standard.[4] For example, when a pathologist looks at a biopsy of ...