A coloured substance that is entirely or almost entirely insoluble in water is called a Pigments. Contrarily, dyes are usually soluble, at least initially, during their use. In general, dyes are frequently inorganic substances while dyes are frequently organic molecules. Ochre, charcoal, and lapis lazuli are dyes with historical and prehistoric relevance.
Pigments exhibit colour because, like all materials, they only absorb particular visible light wavelengths. The wavelength and degree of light absorption are governed by the material's bonding characteristics. Other wavelengths of light are dispersed or reflected. The colour that we see is determined by the spectrum of reflected light. The appearance of Pigments is affected by the light source. The spectrum of sunlight is fairly uniform and has a high colour temperature. Sunlight is regarded as the gold standard for white light. Artificial lighting is less consistent. Color spaces that use numbers to represent colours must specify their light source. Unless otherwise noted, lab colour measurements assume that the measurement was taken under a D65 light source, or "Daylight 6500 K," which is roughly the colour temperature of sunlight. The pigment Rosco R80 "Primary Blue" is exposed to sunlight. The final spectrum and the appearance of blue are the result of the product of the source spectrum and the reflectance spectrum of the pigment. Other substances may influence a color's other properties, such as saturation or lightness. Since ancient times, minerals have been utilised as colouring agents. Early humans decorated their bodies with paint for aesthetic reasons. In a cave in Twin Rivers, close to Lusaka, Zambia, Pigments and paint grinding equipment thought to be between 350,000 and 400,000 years old have been discovered. The original hue of paint was ochre, which is iron oxide. Lapis lazuli was used to create a very popular blue pigment. Mineral and clay-based dyes frequently bear the name of the city or region where they were first mined. Italy's Siena produced Raw Sienna and Burnt Sienna, while Umbria produced Raw Umber and Burnt Umber. Batches of colour were frequently inconsistent prior to the discovery of synthetic dyes and the improvement of methods for extracting mineral Pigments. Manufacturers and experts worked together to develop international standards for classifying, creating, measuring, and testing colours as a result of the growth of the modern colour business. These Pigments were among the simplest to create, and chemists based modern colours on the originals. Colors mined from the original ore bodies were more consistent, but the place names remained. Red ochre, anhydrous Fe2O3, and hydrated Yellow Ochre (Fe2O3.H2O) are also found in many Paleolithic and Neolithic cave paintings. Charcoal or carbon black has also been used as a black pigment since prehistoric times. Any coloured component of plant or animal cells is referred to as a pigment in biology. dyes are found in numerous biological tissues, including the skin, eyes, fur, and hair (such as melanin). Specialized cells called chromatophores, which are controlled by animals like the chameleon and octopus, are frequently responsible for animal skin colour. The quantity or makeup of Pigments in plant, animal, certain protozoan, or fungal cells is influenced by a variety of factors. For instance, animals' levels of melanin production are impacted by the condition known as albinism. The biological functions of pigmentation in organisms include camouflage, mimicry, aposematism (warning), sexual selection, other types of signalling, photosynthesis (in plants), as well as more fundamental physical functions like sun protection.
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