Color The science of color is sometimes called chromatics, colorimetry, or simply color science. It includes the study of 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 is commonly referred to simply as "light"). Electromagnetic radiation is characterized by its wavelength (or frequency) and its intensity. When the wavelength is within the visible spectrum (the range of wavelengths humans can perceive, approximately from 390 nm to 700 nm), it is known as "visible light". Most light
Color difference Commonly used values are 2:1 for acceptability and 1:1 for the threshold of imperceptibility. The distance of a color formula_27 to a reference formula_28 is: CMC l:c is designed to be used with D65 and the CIE Supplementary Observer. The formula is not a metric but rather a quasimetric because it violates symmetry, parameter T is based on the hue of the formula_32 alone. This reference color means that the color difference from the first color to the second color is different than the color distance from the second color is to the first. Tolerancing concerns the question "What is