Cadmium pigments

File:Cadmium-Hemimorphite-Smithsonite-nex15a.jpg crusted on smithsonite]]

File:Cadmium sulfide.jpg

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 {{convert|3000|C}}.{{cite web |url=http://www.cadmium.org/pg_n.php?id_menu=13 |title=Cadmium Pigments |access-date=30 November 2010 |archive-url=https://web.archive.org/web/20110212203609/http://www.cadmium.org/pg_n.php?id_menu=13 |archive-date=12 February 2011 |url-status=dead }} 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 (CdS), C.I. Pigment Yellow 37.
• Cadmium sulfoselenide is a solid solution of CdS and cadmium selenide; 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 to give a vivid 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.{{Citation |url=http://www.webexhibits.org/pigments/indiv/history/cdyellow.html |title=History of Cadmium Yellow |work=Pigments Through the Ages |first=Michael |last=Douma |year=2008 |access-date=2013-07-31}} A cadmium yellow paint was frequently used on Bob Ross' TV show The Joy of Painting.

In July 2023, the brilliance of cadmium yellow (especially "Cadmium Yellow Lemon No.1 by Lucien Lefebvre-Foinet") used by some modern artists, was reported to have faded over time due to chemical degradation.{{cite news |last=Korne;l |first=Katherine |title=Why Miró's Yellows Have Lost Their Brilliance - Researchers discovered that a particular brand of paint favored by the Spanish artist had an atomic structure that predisposed it to degradation. |url=https://www.nytimes.com/2023/09/18/science/joan-miro-yellow-paint-fading.html |date=18 September 2023 |work=The New York Times |url-status=live |archiveurl=https://archive.today/20230918123316/https://www.nytimes.com/2023/09/18/science/joan-miro-yellow-paint-fading.html |archivedate=18 September 2023 |accessdate=19 September 2023 }}{{cite journal |author=Lobon, Mar Gomez |display-authors=et al. |title=A study of cadmium yellow paints from Joan Miró's paintings and studio materials preserved at the Fundació Miró Mallorca |date=17 July 2023 |journal=Heritage Science |volume=11 |issue=145 |doi=10.1186/s40494-023-00987-4 |doi-access=free |hdl=10278/5030880 |hdl-access=free }}

File:Cadmium color rods.jpg colored with cadmium compounds.]]

Cadmium compounds are utilized in coloring borosilicate glass{{cite web|url=http://www.adamschittenden.com/Borosilicate_Glass_Material_Properties.php |title= Borosilicate glass material properties |publisher= Adams & Chittenden Scientific Glass |access-date= 12 April 2019}} used by artists in lampworking. 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.{{Cite web|url=https://glassalchemy.com/pages/about-us|title=About Us|publisher=Glass Alchemy|access-date=2018-11-05}}

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. CdS has a boiling point of 980 °C (1,796 °F), putting its maximum temperature tolerance as a pigment not far above the working temperature range for borosilicate, which has a softening point of approximately 850 °C (1,562 °F).{{Cite book|title=Vacuum Physics and Technology|date=1980|edition=1st|publisher=Academic Press|editor1-last=Weissler |editor1-first=G. L. |editor2-last=Carlson |editor2-first=R. W.|isbn=9780124759145|location=New York|oclc=5170642}}{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/14783|title=Cadmium sulfide|website=PubChem|publisher=NCBI|access-date=2018-11-05}}

File:Cadmium orange cast iron pot.JPG pot]]

Cadmium sulfide is not very toxic ({{LD50}} 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.{{cite journal |doi=10.1016/j.scitotenv.2018.12.096|title=Cadmium pigments in consumer products and their health risks |year=2019 |last1=Turner |first1=Andrew |journal=Science of the Total Environment |volume=657 |pages=1409–1418 |pmid=30677907 |bibcode=2019ScTEn.657.1409T |hdl=10026.1/13186 |s2cid=59252725 |hdl-access=free }}{{cite web|title=Cadmium (EHC 134, 1992)|url=http://www.inchem.org/documents/ehc/ehc/ehc134.htm|access-date=5 December 2018|website=InChem|publisher=IPCS}} 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.{{cite web |url=http://www.paintmaking.com/yellow.htm |title=Yellow |website=Making Artist's Paint |first=Tony |last=Johansen |date=2006-05-06 |access-date=2013-07-31 |archive-url=https://web.archive.org/web/20120205201823/http://www.paintmaking.com/yellow.htm |archive-date=5 February 2012 |url-status=dead }}

In December 2013, the Swedish Chemicals Agency (KEMI) proposed a case to the European Chemicals Agency (ECHA) 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.{{cite journal|last1=Kawasaki|first1=Takashi|last2=Kono|first2=Koichi|last3=Dote|first3=Tomotaro|last4=Usuda|first4=Kan|last5=Shimizu|first5=Hiroyasu|last6=Dote|first6=Emi|date=2004|title=Markers of cadmium exposure in workers in a cadmium pigment factory after changes in the exposure conditions|journal=Toxicology and Industrial Health|language=en|volume=20|issue=1–5|pages=51–56|doi=10.1191/0748233704th189oa|pmid=15807408|bibcode=2004ToxIH..20...51K |s2cid=31862331}}{{cite journal|last1=Kim|first1=Hyun-Soo|last2=Kim|first2=Yeo-Jin|last3=Seo|first3=Young-Rok|date=December 2015|title=An Overview of Carcinogenic Heavy Metal: Molecular Toxicity Mechanism and Prevention|journal=Journal of Cancer Prevention|volume=20|issue=4|pages=232–240|doi=10.15430/JCP.2015.20.4.232|issn=2288-3649|pmc=4699750|pmid=26734585}}{{cite journal|last1=Järup|first1=Lars|date=1 December 2003|title=Hazards of heavy metal contamination|journal=British Medical Bulletin|language=en|volume=68|issue=1|pages=167–182|doi=10.1093/bmb/ldg032|issn=0007-1420|pmid=14757716|doi-access=free}} KEMI's proposal was ultimately declined.

In a June 2015 article of Just Paint, published by Golden Artist Colors, 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."{{cite web |last1=Gavett |first1=Ben |title=Will Cadmium Colors Always be on the Palette? (Part 2) |url=https://www.justpaint.org/will-cadmium-colors-always-be-on-the-palette-part-2/ |website=Just Paint |date=February 2015 |publisher=Golden Artist Colors, Inc. |access-date=5 December 2018}}{{cite web |title=Annex XV restriction: Report proposal for a restriction |url=https://echa.europa.eu/documents/10162/13641/annex_xv_cd_in_artist_paints_en.pdf |publisher=ECHA |access-date=5 December 2018}}

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.{{cite web |last1=Hoakley |title=Pigment: Controversial Cadmiums, yellow to red |url=https://eclecticlight.co/2018/06/15/pigment-controversial-cadmiums-yellow-to-red/ |website=The Eclectic Light Company |access-date=5 December 2018 |language=en |date=15 June 2018}}

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

Grapes, Lemons, Pears, and Apples 1887 Vincent van Gogh.jpg | Vincent van Gogh, "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, "Wheatstacks (Sunset, Snow Effect)" (1890–91)

Monet-Still-Life-with-Apples-and-Grapes-1880.jpg | Claude Monet, "Still Life with Apples and Grapes" (1880)

• List of inorganic pigments
• Red pigments

{{Reflist}}

• {{cite book|last1=Fiedler|first1=I.|last2=Bayard|first2=M. A.|contribution=Cadmium Yellows, Oranges and Reds|title=Artists' Pigments: A handbook of their history and characteristics|volume=1|editor-last=Feller|editor-first=R. L.|publisher=Oxford University Press|date=1986|isbn=9780894680861|pages=65–108|url= https://www.nga.gov/research/publications/pdf-library/artists-pigments-vol-1.html}}

• {{cite web|archive-url=https://web.archive.org/web/20061210213049/http://www.npi.gov.au/database/substance-info/profiles/17.html|url=http://www.npi.gov.au/database/substance-info/profiles/17.html|url-status=dead|archive-date=2006-12-10|website=National Pollutant Inventory|title=Cadmium and compounds}}
• {{cite web |url=http://webexhibits.org/pigments/indiv/overview/cdyellow.html |title=Cadmium yellow | work=Pigments through the Ages |publisher=WebExhibits}}
• {{cite web |url=http://webexhibits.org/pigments/indiv/overview/cdorange.html |title=Cadmium orange | work=Pigments through the Ages |publisher=WebExhibits}}
• {{cite web |url=http://webexhibits.org/causesofcolor/10.html |title=Why are cinnabar, vermilion, and cadmium orange colored? | work=Causes of Color |publisher=WebExhibits}}
• [http://colourlex.com/project/cadmium-yellow/ Cadmium yellow], ColourLex
• [http://colourlex.com/project/cadmium-orange/ Cadmium orange], ColourLex
• [http://colourlex.com/project/cadmium-red/ Cadmium red], ColourLex
• [http://colourlex.com/project/cadmium-green/ Cadmium green], ColourLex

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Pigments

Category:Inorganic pigments

Category:Cadmium compounds

Category:Sulfides

Category:Shades of red

Category:Shades of orange

Category:Shades of green

Category:Shades of yellow