Cadmium pigments

Source: Wikipedia, the free encyclopedia.
Cadmium orange
 
CIELChuv (L, C, h)
(66, 101, 34°)
Source[1] Charts
ISCC–NBS descriptorStrong orange
B: Normalized to [0–255] (byte)
Cadmium red
 
CIELChuv (L, C, h)
(48, 155, 11°)
SourceColorHexa
ISCC–NBS descriptorVivid reddish orange
B: Normalized to [0–255] (byte)
Cadmium yellow
 
CIELChuv (L, C, h)
(95, 104, 82°)
SourceColorHexa[2]
ISCC–NBS descriptorVivid greenish yellow
B: Normalized to [0–255] (byte)
Cadmium green
 
CIELChuv (L, C, h)
(39, 44, 142°)
SourceColorHexa
ISCC–NBS descriptorDeep yellowish green
B: Normalized to [0–255] (byte)

Cadmium pigments are a class of

sulfoselenides, as well as compounds with other metals.[4]

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

Cadmium-rich hemimorphite crusted on smithsonite
Cadmium sulfide

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 3,000 °C (5,430 °F).[5] 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:

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.

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.[7][8]

Coloring art glass

Borosilicate glass colored with cadmium compounds.

Cadmium compounds are utilized in coloring borosilicate glass[9] 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.[10]

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 (1,800 °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 (1,560 °F).[11][12]

Safety

cast-iron
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.[13][14] Acute exposure to cadmium vapors can arise from welding near cadmium pigments.[4]

The cadmium pigments have been partially replaced by azo pigments, which have significantly inferior lightfastness.[15]

In December 2013, the Swedish 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.[16][17][18]
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."[19][20]

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.[21]

Examples of cadmium pigments in art

See also

References

  1. ^ "THE MOTHER OF ALL HTML COLOR CHARTS index and reference | Color World | Color, Chart, Color names". tx4.us. Archived from the original on 22 November 2012. Retrieved 11 May 2019.
  2. ^ "Cadmium yellow / #fff600 hex color". ColorHexa. Retrieved 19 December 2022.
  3. ^ "MEPs Ban Cadmium from Power Tool Batteries and Mercury from Button Cells". European Parliament. 10 October 2013.
  4. ^
    ISBN 978-3527306732
    .
  5. ^ "Cadmium Pigments". Archived from the original on 12 February 2011. Retrieved 30 November 2010.
  6. ^ Douma, Michael (2008), "History of Cadmium Yellow", Pigments Through the Ages, retrieved 31 July 2013
  7. ^ Korne;l, Katherine (18 September 2023). "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". The New York Times. Archived from the original on 18 September 2023. Retrieved 19 September 2023.{{cite news}}: CS1 maint: multiple names: authors list (link)
  8. hdl:10278/5030880
    .
  9. ^ "Borosilicate glass material properties". Adams & Chittenden Scientific Glass. Retrieved 12 April 2019.
  10. ^ "About Us". Glass Alchemy. Retrieved 5 November 2018.
  11. OCLC 5170642
    .
  12. ^ "Cadmium sulfide". PubChem. NCBI. Retrieved 5 November 2018.
  13. S2CID 59252725
    .
  14. ^ "Cadmium (EHC 134, 1992)". InChem. IPCS. Retrieved 5 December 2018.
  15. ^ Johansen, Tony (6 May 2006). "Yellow". Making Artist's Paint. Archived from the original on 5 February 2012. Retrieved 31 July 2013.
  16. S2CID 31862331
    .
  17. PMID 26734585
    .
  18. PMID 14757716
    .
  19. ^ Gavett, Ben (February 2015). "Will Cadmium Colors Always be on the Palette? (Part 2)". Just Paint. Golden Artist Colors, Inc. Retrieved 5 December 2018.
  20. ^ "Annex XV restriction: Report proposal for a restriction" (PDF). ECHA. Retrieved 5 December 2018.
  21. ^ Hoakley (15 June 2018). "Pigment: Controversial Cadmiums, yellow to red". The Eclectic Light Company. Retrieved 5 December 2018.

Further reading

External links


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