Cadmium pigments are a class of
pigments 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nickel–cadmium batteries, which have been replaced by other rechargeable nickel-chemistry cell varieties such as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
T ...
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
paints, as they can add life and vibrancy to
renderings. Their greatest use is in the coloring of
plastics 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 of CdS and
cadmium selenide
Cadmium selenide is an inorganic compound with the formula Cd Se. It is a black to red-black solid that is classified as a II-VI semiconductor of the n-type. Much of the current research on this compound is focused on its nanoparticles.
Stru ...
; depending on the
sulfur-to-
selenium 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,
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 (the original
vermilion) 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 bet ...
''
The Joy of Painting''.
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
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 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 near cadmium pigments.
[
The cadmium pigments have been partially replaced by azo pigments, which have significantly inferior lightfastness.
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 Restrict ...
) 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
Reach or REACH may refer to:
Companies and organizations
* Reach plc, formerly Trinity Mirror, large British newspaper, magazine, and digital publisher
* Reach Canada, an NGO in Canada
* Reach Limited, an Asia Pacific cable network company ...
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 o ...
, 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-Impressionist painter who posthumously became one of the most famous and influential figures in Western art history. In a decade, he created about 2,100 artworks, inclu ...
, "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 , 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 ...
, "Still Life with Apples and Grapes" (1880)
See also
* List of inorganic pigments
The following list includes commercially or artistically important inorganic pigments of natural and synthetic origin..
Purple pigments
Aluminum pigments
* Ultramarine violet: (PV15) - a synthetic or naturally occurring sulfur containing silic ...
* Red pigments
Red pigments are materials, usually made from minerals, used to create the red colors in painting and other arts. The color of red and other pigments is determined by the way it absorbs certain parts of the spectrum of visible light and reflects ...
References
Further reading
*
External links
*
*
*
*
Cadmium yellow
ColourLex
Cadmium orange
ColourLex
Cadmium red
ColourLex
{{DEFAULTSORT:Cadmium Pigments
Pigments
Inorganic pigments
Cadmium compounds
Sulfides
Shades of red
Shades of orange
Shades of green
Shades of yellow