Information about Cadmium Yellow
Cadmium pigments are a class of pigments that have cadmium as one of the chemical components.
Most of cadmium produced worldwide is used in the production of Ni-Cd Batteries, but about half the remaining consumption, which is about 2,000 tons annually, is used to produce colored cadmium pigments. The principal pigments are a family of yellow/orange/red cadmium sulfides and sulfoselenides. Cadmium yellow is cadmium sulfide (CdS), cadmium red is cadmium selenide (CdSe) and cadmium orange is an intermediate cadmium sulfoselenide. Cadmium yellow is sometimes mixed with viridian to give a bright, pale green mixture called cadmium green.
Brilliantly colored, with good permanence and tinting power, Cadmium Yellow, Cadmium Orange, and Cadmium Red are familiar artist colors, but of little use in architectural paints. Their greatest use is in the coloring of plastics and specialty paints which must resist processing or service temperatures up to 300°C. The color-fastness or permanence of cadmium requires protection from a tendency to slowly form carbonate salts with exposure to air. Most paint vehicles accomplish this, but cadmium colors will fade in fresco or mural painting. Cadmium pigments can also color glass and ceramic glazes, not by solution, but colloidal dispersion within the glass. The lenses of red stoplights use this technique.
Cadmium sulfide and a mixture of cadmium sulfide with cadmium selenide are commonly used as pigments in artist's paints. They have an excellent reputation for color permanence although this is partially based on two reasons which are not necessarily directly related to their properties:
Nowadays, the cadmium pigments have been partially replaced by azo pigments. These are similar in lightfastness to the cadmium colors and have the advantage of both being cheaper and non-toxic. With respect to lightfastness the lemon yellow cadmium pigment is an exception: the azo-variety is highly superior in light-fastness. In some countries, such as Australia, consumer activists such as Michael Vernon were successful in banning the use of cadmium pigments in plastics that could be used for toy manufacture, owing to the toxicity of cadmium.
Brilliantly colored, with good permanence and tinting power, Cadmium Yellow, Cadmium Orange, and Cadmium Red are familiar artist colors, but of little use in architectural paints. Their greatest use is in the coloring of plastics and specialty paints which must resist processing or service temperatures up to 300°C. The color-fastness or permanence of cadmium requires protection from a tendency to slowly form carbonate salts with exposure to air. Most paint vehicles accomplish this, but cadmium colors will fade in fresco or mural painting. Cadmium pigments can also color glass and ceramic glazes, not by solution, but colloidal dispersion within the glass. The lenses of red stoplights use this technique.
Cadmium sulfide and a mixture of cadmium sulfide with cadmium selenide are commonly used as pigments in artist's paints. They have an excellent reputation for color permanence although this is partially based on two reasons which are not necessarily directly related to their properties:
- when introduced, there were hardly any stable pigments in the yellow to red range, especially orange and bright red was very troublesome, when the cadmium pigments replaced e.g. mercury sulfide (the original vermilion), the light-fastness was greatly improved,
- companies sell the cadmium-containing paints at premium price. Although the pigments are certainly more expensive, the premium price is often not fully justifiable, with reasons more in the marketing area than in the actual raw material cost.
Nowadays, the cadmium pigments have been partially replaced by azo pigments. These are similar in lightfastness to the cadmium colors and have the advantage of both being cheaper and non-toxic. With respect to lightfastness the lemon yellow cadmium pigment is an exception: the azo-variety is highly superior in light-fastness. In some countries, such as Australia, consumer activists such as Michael Vernon were successful in banning the use of cadmium pigments in plastics that could be used for toy manufacture, owing to the toxicity of cadmium.
External links
- National Pollutant Inventory - Cadmium and compounds
- Cadmium yellow. Pigments through the Ages. WebExhibits.
- Cadmium orange. Pigments through the Ages. WebExhibits.
- Why are cinnabar, vermilion, and cadmium orange colored?. Causes of Color. WebExhibits.
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.
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Cadmium (IPA: /ˈkædmiəm/) is a chemical element in the periodic table that has the symbol Cd and atomic number 48.
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Cadmium (IPA: /ˈkædmiəm/) is a chemical element in the periodic table that has the symbol Cd and atomic number 48.
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nickel-cadmium battery (commonly abbreviated NiCd and pronounced "nye-cad") is a popular type of rechargeable battery using nickel(IV) oxide and metallic cadmium as electrodes.
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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.
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The term sulfide (also spelled sulphide, see spelling) refers to several types of chemical compounds containing sulfur in its lowest oxidation number of −2.
Formally, "sulfide" is the dianion, S2−
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Formally, "sulfide" is the dianion, S2−
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Cadmium sulfide is a chemical compound with the formula CdS. It exists in nature as two different minerals, greenockite and hawleyite.
Greenockite forms hexagonal crystals with the wurtzite structure. It has a yellowish colour with specific gravity of 4.
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Greenockite forms hexagonal crystals with the wurtzite structure. It has a yellowish colour with specific gravity of 4.
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Cadmium selenide (CdSe) is a solid, binary compound of cadmium and selenium. Common names for this compound are cadmium (II) selenide, cadmium selenide, and cadmoselite.
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Viridian is a blue-green pigment, a hydrated chromium(III) oxide, of medium saturation and relatively dark in value. It is composed more of green than blue. Actually, it is a dark shade of spring green, the color between green and cyan on the color wheel.
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Paint is any liquid, liquifiable, or mastic composition which after application to a substrate in a thin layer is converted to an opaque solid film.
Paint is used to protect, decorate (such as adding color), or add functionality to an object or surface by covering it
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Paint is used to protect, decorate (such as adding color), or add functionality to an object or surface by covering it
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Plastic is the general term for a wide range of synthetic or semisynthetic polymerization products. They are composed of organic condensation or addition polymers and may contain other substances to improve performance or economics.
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Vermilion, also spelled vermillion, when found naturally-occurring, is an opaque orangeish red pigment, used since antiquity, originally derived from the powdered mineral cinnabar. Chemically the pigment is mercuric sulfide, HgS.
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Azo pigments are solid, colorless particles (typically earths or clays), which have been colored using an azo compound. The azo compounds are highly colored organic molecules.
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Anthem
Advance Australia Fair [1]
Capital Canberra
Largest city Sydney
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Advance Australia Fair [1]
Capital Canberra
Largest city Sydney
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Michael 'Mike' Vernon A.M. (2 April 1932 – 6 November 1993) was a prominent Australian consumer activist. Vernon was born in Portsmouth, United Kingdom in 1932 to John Ernest Vernon (a writer in the Royal Navy) and Caroline Vernon (nee Clark) (later a cryptologist in the
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