Cadmium pigments are a class of

pigment A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

s that contain

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

. Most of the cadmium produced worldwide has been for use in rechargeable nickel–cadmium batteries, which have been replaced by other rechargeable nickel-chemistry cell varieties such as NiMH cells, but about half of the remaining consumption of cadmium, which is approximately annually, is used to produce colored cadmium pigments. The principal pigments are a family of yellow, orange and red cadmium

sulfide Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds lar ...

s and

sulfoselenide In chemistry, a selenosulfide refers to distinct classes of inorganic and organic compounds containing sulfur and selenium. The organic derivatives contain Se-S bonds, whereas the inorganic derivatives are more variable. Organic selenosulfides ...

s, as well as compounds with other metals. Cadmium is toxic to humans and other animals in very small amounts, especially when it is inhaled, which often happens when working with powdered pigment or breathing the dust from chalk pastels. As a result, it is not appropriate for children to use any art supplies that contain cadmium pigments. However, because the pigments have some desirable qualities, such as resistance to fading, some adult artists continue to use them.

Artists' paints

Brilliantly colored, with good permanence and tinting power, cadmium yellow, cadmium orange and cadmium red are familiar artists’ colors, and are frequently employed as architectural

paint Paint is any pigmented liquid, liquefiable, or solid mastic composition that, after application to a substrate in a thin layer, converts to a solid film. It is most commonly used to protect, color, or provide texture. Paint can be made in many ...

s, as they can add life and vibrancy to renderings. Their greatest use is in the coloring of

plastic Plastics are a wide range of synthetic or semi-synthetic materials that use polymers as a main ingredient. Their plasticity makes it possible for plastics to be moulded, extruded or pressed into solid objects of various shapes. This adaptab ...

s and specialty paints, which must resist processing or service temperatures up to . The colorfastness or permanence of cadmium requires protection from the element's 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. The following are commonly used as pigments in artists' paints: * Cadmium yellow is

cadmium sulfide Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid.Egon Wiberg, Arnold Frederick Holleman (2001''Inorganic Chemistry'' Elsevier It occurs in nature with two different crystal structures as the rare m ...

(CdS), C.I. Pigment Yellow 37. * Cadmium sulfoselenide is a

solid solution A solid solution, a term popularly used for metals, is a homogenous mixture of two different kinds of atoms in solid state and have a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The word ...

of CdS and

cadmium selenide Cadmium selenide is an inorganic compound with the formula Cadmium, CdSelenide, Se. It is a black to red-black solid that is classified as a II-VI semiconductor of the n-type semiconductor, n-type. Much of the current research on this compound i ...

; depending on the

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

-to-

selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...

ratio, C.I. Pigment Orange 20 or C.I. Pigment Red 108 is obtained. * Zinc cadmium sulfide is a greenish, solid solution of CdS and

zinc sulfide Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various i ...

, C.I. Pigment Yellow 35. * Cadmium yellow is sometimes mixed with

viridian Viridian is a blue-green pigment, a hydrated chromium(III) oxide, of medium saturation and relatively dark in value. It is composed of a majority of green, followed by blue. Specifically, it is a shade of spring green, which places the color b ...

to give a bright, pale green mixture called cadmium green. When first introduced, there were hardly any stable pigments in the yellow-to-red range, with orange and bright red being very troublesome. The cadmium pigments eventually replaced compounds such as

mercury(II) sulfide Mercury sulfide, or mercury(II) sulfide is a chemical compound composed of the chemical elements mercury (element), mercury and sulfur. It is represented by the chemical formula HgS. It is virtually insoluble in water. Crystal structure HgS ...

(the original

vermilion Vermilion (sometimes vermillion) is a color, color family, and pigment most often made, since ancient history, antiquity until the 19th century, from the powdered mineral cinnabar (a form of mercury sulfide, which is toxic) and its correspondi ...

) with greatly improved lightfastness. Cadmium pigments are known for excellent lightfastness, although the lighter shades can fade in sunlight. A cadmium yellow paint was frequently used on

Bob Ross Robert Norman Ross (October 29, 1942 – July 4, 1995) was an American painter, art instructor, and television host. He was the creator and host of ''The Joy of Painting'', an instructional television program that aired from 1983 to 1994 on ...

TV show A television show – or simply TV show – is any content produced for viewing on a television set which can be broadcast via over-the-air, satellite, or cable, excluding breaking news, advertisements, or trailers that are typically placed betw ...

The Joy of Painting ''The Joy of Painting'' is an American half-hour instructional television show created and hosted by painter Bob Ross which ran from January 11, 1983 to May 17, 1994. In most episodes, Ross taught techniques for landscape oil painting, completi ...

''.

Coloring art glass

Cadmium compounds are utilized in coloring

borosilicate glass Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10−6 K−1 at 20 °C), ma ...

used by artists in

lampworking Lampworking is a type of glasswork in which a torch or lamp is used to melt the glass. Once in a molten state, the glass is formed by blowing and shaping with tools and hand movements. It is also known as flameworking or torchworking, as the moder ...

. The palette is often referred to as "cadmium colors" or "cadmium-based colors" and is marked by uniquely bright and saturated tones not found in other colored glass. Cadmium pigments used in borosilicate have a relatively short history, with the first commercial formulations hitting the market in 2000 under the name Crayon Colors by Henry Grimmett of Glass Alchemy. Cadmium-compound-containing glass exhibits a characteristically low heat tolerance when melted, and therefore must be treated with caution when lampworking to avoid boiling off of the

. CdS has a boiling point of , putting its maximum temperature tolerance as a pigment not far above the working temperature range for borosilicate, which has a softening point of approximately .

Safety

Cadmium sulfide is not very toxic ( above 5,000 mg/kg). Cadmium is introduced into the body most commonly through smoking and the diet. Poisoning by pigments is uncommon but of continuing concern.Acute exposure to cadmium vapors can arise from

welding Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing Fusion welding, fusion. Welding is distinct from lower ...

near cadmium pigments. The cadmium pigments have been partially replaced by

azo pigments Azo dyes are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl and substituted aryl groups. They are a commercially important family of azo compounds, i.e. compounds containing the C-N=N ...

, which have significantly inferior

lightfastness Lightfastness is a property of a colourant such as dye or pigment that describes its resistance to fading when exposed to light. Dyes and pigments are used for example for dyeing of fabrics, plastics or other materials and manufacturing paints or ...

. In December 2013, the Swedish Chemicals Agency (

KEMI Kemi (; sme, Giepma ; smn, Kiemâ; sms, Ǩeeʹmm; Swedish (historically): ''Kiemi'') is a town and municipality of Finland. It is located very near the city of Tornio and the Swedish border. The distance to Oulu is to the south and to Rovani ...

) proposed a case to the European Chemicals Agency (

ECHA The European Chemicals Agency (ECHA; ) is an agency of the European Union which manages the technical and administrative aspects of the implementation of the European Union regulation called Registration, Evaluation, Authorisation and Restricti ...

) in favor of restricting or banning cadmium use in artists’ paints, as cadmium in pigments used in other types of paints was already restricted and regulated via TARIC codes and REACH Annex XVII. This proposal stated that cadmium in the body leads to increased risk of bone fractures and breast cancer as well as an array of environmental impacts, and that paint washed down the drain is absorbed by crops that are then consumed, increasing the average dietary cadmium intake. This can cause an array of health effects, including kidney and liver damage, skeletal damage, several types of cancers and death. KEMI's proposal was ultimately declined. In a June 2015 article of ''Just Paint,'' published by

Golden Artist Colors Golden Artist Colors, or simply Golden, is an U.S. manufacturing company that focuses on paints used in fine art, decoration, and crafts. Based in New Berlin, New York, the company produces a line of acrylic paints that includes some recreations ...

, the company argued against KEMI's proposal, offering that "There are no alternatives that match all of the characteristics of cadmium pigments." This statement was also included in Golden's response to KEMI's request for information on cadmium-pigmented artists’ paints while the agency was composing its ban proposal. The article also stated that a ban would be technically feasible for some artists, but not all, and that "cadmium colors are not for use by children, should not be spray applied or sanded, and unless one is properly protected from exposure and in a non-household setting, use of dry cadmium pigment should be avoided." Inhalation poses the greatest risk from cadmium pigments, though the chemical is very low-risk when sealed within a pigment particle because of its insolubility. The use of chalk pastels containing cadmium colors is among the highest risks for artists, as these pastels create a dust that can be inhaled.

Examples of cadmium pigments in art

Winslow Homer - Hunter in the Adirondacks (1892).jpg ,

Winslow Homer Winslow Homer (February 24, 1836 – September 29, 1910) was an American landscape painter and illustrator, best known for his marine subjects. He is considered one of the foremost painters in 19th-century America and a preeminent figure in ...

, "Hunter in the Adirondacks" (1892) Grapes, Lemons, Pears, and Apples 1887 Vincent van Gogh.jpg ,

Vincent van Gogh Vincent Willem van Gogh (; 30 March 185329 July 1890) was a Dutch Post-Impressionism, Post-Impressionist painter who posthumously became one of the most famous and influential figures in Western art history. In a decade, he created about 2 ...

, "Grapes, Lemons, Pears, and Apples" (1887) 1278 Wheatstacks (Sunset, Snow Effect), 1890-91, 65.3 x 100.4 cm, 25 11-16 x 39 1-2 in., The Art Institute of Chicago.jpg ,

Claude Monet Oscar-Claude Monet (, , ; 14 November 1840 – 5 December 1926) was a French painter and founder of impressionist painting who is seen as a key precursor to modernism, especially in his attempts to paint nature as he perceived it. During ...

, "Wheatstacks (Sunset, Snow Effect)" (1890–91) Monet-Still-Life-with-Apples-and-Grapes-1880.jpg ,

, "Still Life with Apples and Grapes" (1880)

References

External links

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Cadmium yellow
ColourLex
Cadmium orange
ColourLex
Cadmium red
ColourLex {{DEFAULTSORT:Cadmium Pigments

Pigments A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compou ...

Inorganic pigments Cadmium compounds Sulfides Shades of red Shades of orange Shades of green Shades of yellow