Color

Color (American English) or colour (Commonwealth English) is the visual perceptual property corresponding in humans to the categories called red, blue, yellow, etc. Color derives from the spectrum of light (distribution of light power versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects or materials based on their physical properties such as light absorption, reflection, or emission spectra. By defining a color space colors can be identified numerically by their coordinates.

Because perception of color stems from the varying spectral sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance.

The science of color is sometimes called chromatics, colorimetry, or simply color science. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as light).

Yellow

Yellow /ˈjɛloʊ/ is the color of gold, butter, and ripe lemons. In the spectrum of visible light, and in the traditional color wheel used by painters, yellow is found between green and orange. It is a primary color in subtractive color, used in color printing, along with cyan, magenta, and black.

According to surveys in Europe, Canada and the United States, yellow is the color people most often associate with amusement, optimism, gentleness, and spontaneity, but also with duplicity, envy, jealousy, avarice, and, in the U.S., with cowardice. It plays an important role in Asian culture, particularly in China, where it is seen as the color of happiness, glory, wisdom, harmony and culture.

Etymology and definitions

The word yellow comes from the Old English geolu, geolwe (oblique case), meaning "yellow, yellowish", derived from the Proto-Germanic word gelwaz "yellow". It has the same Indo-European base, gʰel-, as the word yell; gʰel- means both bright and gleaming, and to cry out. Yellow is a color which cries out for attention.