News tagged with pigment

New understanding of how we see colors

(Medical Xpress)—Scientists have until now not fully understood how animals see in color, since visual pigments in eyes contain exactly the same chromophore (light absorbing segment of the molecule) and yet can absorb different ...

Dec 07, 2012
popularity 4.6 / 5 (11) | comments 0 | with audio podcast report

Eye color may indicate risk for serious skin conditions

Eye color may be an indicator of whether a person is high-risk for certain serious skin conditions. A study, led by the University of Colorado School of Medicine, shows people with blue eyes are less likely to have vitiligo. ...

May 06, 2012
popularity 4.6 / 5 (10) | comments 0 | with audio podcast

Laser treatment can make your brown eyes blue

Just like the old Crystal Gayle song, a new laser technology could soon allow you to turn those boring brown eyes of your to a rich and beautiful blue. But you better make sure that blue eyes are what you really want because ...

Nov 04, 2011
popularity 4 / 5 (11) | comments 21 | with audio podcast report

Grapes may help prevent age-related blindness

Can eating grapes slow or help prevent the onset of age-related macular degeneration (AMD), a debilitating condition affecting millions of elderly people worldwide? Results from a new study published in Free Radical Biology an ...

Jan 12, 2012
popularity 4.3 / 5 (9) | comments 1 | with audio podcast

Cells from skin create model of blinding eye disease

For the first time, Wisconsin researchers have taken skin from patients and, using induced pluripotent stem cell (iPSC) technology, turned them into a laboratory model for an inherited type of macular degeneration.

Nov 08, 2012
popularity 5 / 5 (4) | comments 0 | with audio podcast

Giant hogweed can cause burns and blindness

(PhysOrg.com) -- The U.S Department of Agriculture is warning residents in a variety of states to be on the lookout for the Heracleum Mantegazzianum, or giant hogweed. This plant in native to Central Asia ...

Jul 11, 2011
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Why animals don't have infrared vision

On rare occasion, the light-sensing photoreceptor cells in the eye misfire and signal to the brain as if they have captured photons, when in reality they haven't. For years this phenomenon remained a mystery. Reporting in ...

Jun 09, 2011
popularity 4.3 / 5 (4) | comments 3 | with audio podcast

Pigment

A pigment is the 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 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 matrix), a relatively neutral or colorless material that acts as a binder.

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.

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.

This text uses material from Wikipedia licensed under CC BY-SA