 Pigment. The pigment is a material that changes the color of reflected or transmitted light as the result of wavelength selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which the material emits light. Most materials selectively absorb certain wavelength lengths of light. Materials that humans have chosen and developed for use as pigments usually have special properties that make them useful for coloring other materials. The 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 colorants, usually ground into a fine powder. For use in paint, this powder is added to a binder or vehicle a relatively neutral or color-lose material that suspends the pigment and gives the paint its adhesion. A distinction is usually made between the pigment, which is insoluble in its 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 add is either a pigment or a dye depending on the vehicle involved. In some cases, the pigment can be manufactured from a dye by precipitating a soluble dye with a metallic salt. The resulting pigment is called a lake pigment. The term biological pigment is used for all colored substances independent of their solubility. In 2006, around 7.4 million tons of inorganic, organic and special pigments were marketed worldwide. Asia has the highest rate on a quantity basis followed by Europe and North America. The global demand on pigments was roughly $20.5 billion in 2009.