Pigments and reflective media

Pigments are chemicals that selectively absorb and reflect different spectra of light. When a surface is painted with a pigment, light hitting the surface is reflected, minus some wavelengths. This subtraction of wavelengths produces the appearance of different colors. Most paints are a blend of several chemical pigments, intended to produce a reflection of a given color. Pigment manufacturers assume the source light will be white, or of roughly equal intensity across the spectrum. If the light is not a pure white source (as in the case of nearly all forms of artificial lighting), the resulting spectrum will appear a slightly different color. Red paint, viewed under blue light, may appear black. Red paint is red because it reflects only the red components of the spectrum. Blue light, containing none of these, will create no reflection from red paint, creating the appearance of black. White is the color of pure snow or milk. It is the color of light that contains all of the wavelengths of the visible spectrum without absorption. It is the opposite of black.[1] In Western culture, white is the color most often associated with innocence, perfection, the good, honesty, cleanliness, the beginning, the new, neutrality, lightness, and exactitude. White was one of the first colors used by paleolithic artists; they used lime white, made from ground calcite or chalk,[6] sometimes as a background, sometimes as a highlight, along with charcoal and red and yellow ochre in their vivid cave paintings.[7] In ancient Egypt, white was connnected with the goddess Isis. The priests and priestesses of Isis dressed only in white linen, and it was used to wrap mummies.[8] In Greece and other ancient civilizations, white was often associated with mother's milk. In Greek mythology, the god Zeus was nourished at the breast of the nymph Amalthee. In the Talmud, milk was one of four sacred substances, along with wine, honey, and the rose.[9] The ancient Greeks saw the world in terms of darkness and light, so white was a fundamental color. According to Pliny the Elder in his Natural History, Apelles (4th century BC) and the other famous painters of ancient Greece used only four colors in their paintings; white, red, yellow and black;[10] For painting, the Greeks used lead white, made by a long and laborious process. A plain white toga, known as a toga virilis, was worn for ceremonial occasions by all Roman citizens over the age of 14-18. Magistrates and certain priests wore a toga praetexta, with a broad purple stripe. In the time of the Emperor Augustus, No Roman man was allowed to appear in the Roman forum without a toga. The ancient Romans had two words for white; albus, a plain white, (the source of the word albino); and candidus, a brighter white. A man who wanted public office in Rome wore a white toga brightened with chalk, called a toga candida, the origin of the word candidate. The Latin word candere meant to shine, to be bright. It was the origin of the words candle and candid.[11] In ancient Rome, the priestesses of the goddess Vesta dressed in white linen robes, a white palla or shawl, and a white veil. They protected the sacred fire and the penates of Rome. White symbolized their purity, loyalty, and chastity.[8]