Science reveals secrets of a mummy's portrait

How much information can you get from a speck of purple pigment, no bigger than the diameter of a hair, plucked from an Egyptian portrait that's nearly 2,000 years old? Plenty, according to a new study. Analysis of that speck ...

How the zebrafish got its stripes

Animal patterns—the stripes, spots and rosettes seen in the wild—are a source of endless fascination, and now researchers at the University Bath have developed a robust mathematical model to explain how one important ...

Scientists discover how deep-sea, ultra-black fish disappear

Deep in the ocean, where sunlight barely reaches, Smithsonian scientists and a team of collaborators have discovered one of the blackest materials known: the skin of certain fish. These ultra-black fish absorb light so efficiently ...

Shedding light on the brown color of algae

For many people, algae are just an odorous nuisance on their vacation beach or unwelcome guests in the garden pond and aquarium. This does not take into account, however, the enormous effects these mostly microscopic aquatic ...

Catch and release: Collagen-mediated control of PEDF availability

Cells are like tiny self-contained machines that are constantly fine-tuned in response to both internal and external signals. Some of these signals are induced by extracellular ligands, specialized proteins that bind to specific ...

How did the old masters make their ultramarine?

Researchers at the Rijksmuseum, the University of Amsterdam, VU Amsterdam and the European Synchrotron Radiation Facility (ESRF) have developed a method that reveals how the costly pigment ultramarine was prepared from the ...

Researchers investigate how squid communicate in the dark

In the frigid waters 1,500 feet below the surface of the Pacific Ocean, hundreds of human-sized Humboldt squid feed on a patch of finger-length lantern fish. Zipping past each other, the predators move with exceptional precision, ...

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Pigment

A 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 a material emits light.

Many materials selectively absorb certain wavelengths 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 colourants, usually ground into a fine powder. This powder is added to a vehicle (or binder), a relatively neutral or colorless material that suspends the pigment and gives the paint its adhesion.

The worldwide market for inorganic, organic and special pigments had a total volume of around 7.4 million tons in 2006. Asia has the highest rate on a quantity basis followed by Europe and North America. In 2006, a turnover of 17.6 billion US$ (13 billion euro) was reached mostly in Europe, followed by North America and Asia. The global demand on pigments was roughly US$ 20.5 billion in 2009, around 1.5-2% up from the previous year. It is predicted to increase in a stable growth rate in the coming years. The worldwide sales will increase to US$ 24.5 billion in 2015, and reach US$ 27.5 billion in 2018.

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). The term biological pigment is used for all colored substances independent of their solubility. 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.

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