Information AboutPigment |
| CATEGORIES ABOUT PIGMENT | |
| pigments | |
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pigment in powdered form.]] pigment is chemically identical to natural ultramarine.]] A pigment is a material that changes the Color of Light it Reflects as the result of selective color absorption. This physical process differs from Fluorescence , Phosphorescence , and other forms of Luminescence , in which the material itself emits light. Many materials selectively absorb certain Wavelength s of light. Materials that humans have chosen and developed for use as pigments usually have special properties that make them ideal for coloring other materials. A pigment must have a high Tinting strength relative to the materials it colors. It must be stable in solid form at ambient temperatures. For industrial applications, as well as in the arts, permanence and stability are desirable properties. Pigments that are not permanent are called Fugitive . Fugitive pigments fade over time, or with exposure to light, while some eventually blacken. Pigments are used for coloring Paint , Ink , Plastic , Fabric , Cosmetics , Food and other materials. Most pigments used in Manufacturing and the Visual Arts are dry Colourant s, usually ground into a fine Powder . This powder is added to a vehicle (or matrix), a relatively neutral or colorless material that acts as a Binder . A distinction is usually made between a pigment, which is Insoluble in the vehicle (resulting in a suspension), and a Dye , which either is itself a Liquid or is soluble in its vehicle (resulting in a solution). A colorant can be both a pigment and a dye depending on the vehicle it is used in. In some cases, a pigment can be manufactured from a dye by Precipitating a soluble dye with a metallic salt. The resulting pigment is called a Lake Pigment . BIOLOGICAL PIGMENTS 's distinctive pigmentation reminds potential predators that it is poisonous.]] See Also: Biological pigment In Biology , a pigment is any material in Color of plant or animal cells. Many biological structures, such as Skin , Eye s, Fur and Hair contain pigments (such as Melanin ) in specialized cells called Chromatophores . Many conditions affect the levels or nature of pigments in plant and animal cells. For instance, Albinism is a disorder affecting the level of Melanin production in animals. Pigment color differs from structural colour in that it is the same for all viewing angles, whereas structural color is the result of selective Reflection or Iridescence , usually because of multilayer structures. For example, Butterfly wings typically contain structural color, although many butterflies have cells that contain pigment as well. HISTORY OF PIGMENTS Naturally occurring pigments such as Ochre s and Iron Oxide s have been used as colorants since prehistoric times. Archaeologists have uncovered evidence that early humans used Paint for aesthetic purposes such as body decoration. Pigments and paint grinding equipment believed to be between 350,000 and 400,000 years old have been reported in a Cave at Twin Rivers, near Lusaka, Zambia . Before the Industrial Revolution , the range of color available for art and decorative uses was technically limited. Most of the pigments in use were earth and Mineral pigments, or pigments of biological origin. Pigments from unusual sources such as botanical materials, animal waste, Insect s, and Mollusk s were harvested and traded over long distances. Some colors were costly or impossible to mix with the range of pigments that were available. Blue and Purple came to be associated with Royalty because of their expense. | |||||||||||||||||||||
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