0
$\begingroup$

I have a question about the toxicity of the pigments Cadmium Selenide (Cadmium Red), Cadmium Sulfide (Cadmium Yellow), Mercury Sulfide (Cinnabar or Vermillion) and Lead Oxide (Lead White).

Not long ago the EU banned lead-white pigments from use, even for art. It is now generally impossible to get hold of lead-white oil paint on the internet. However, the cadmium pigments were spared a ban recently. And it is quite easy to find Cinnabar and Vermillion oil paint online even of European production. For example, the dutch company Royal Talens supplies Vermillion paint online, without even warning that it contains mercury: https://www.royaltalens.com/en/catalog/rembrandt-oil-colour/oil-colour-paint-vermillion-311-40ml-tube/

I am not a chemist but my limited knowledge tells me that mercury is a lot more poisonous than lead. How come Cinnabar wasn't banned and what is the relative toxicity of the four pigments I listed, given that they are suspended in oil?

Thank you very much.

$\endgroup$
  • 1
    $\begingroup$ The solubility under relevant conditions is a decisive point. And the concentration of the given pigment. Certainly the places of usage (oil paintings are just one, lead white used to be very widely used). Availability of replacement options was surely taken into account. And then a bit of politics gets mixed in. ;) $\endgroup$ – Karl Mar 8 at 20:55
  • $\begingroup$ @Karl I think that Vermillion would be easily substituted for by various organic red dyes and/or cadmium red. I thought may be lead white was actually more toxic than Cinnabar? So why did the cadmium colors come under attack, are they also more toxic than mercury containing colors? That's something I don't understand. Mainly because I started painting recently and am fascinated by the colors these pigments produce, unlike anything you could ever see in a photo :) $\endgroup$ – iliar Mar 8 at 21:06
  • 4
    $\begingroup$ The toxicity of mercury depends a lot on its form and way of application. The metal could reputedly be swallowed without much harm, inhaling it is more critical, and dimethylmercury is extremely poisonous. Cinnabarit is very resistant to acids and bases. You could likely eat the pure pigment, it would just pass through your digestive tract. $\endgroup$ – Karl Mar 8 at 21:12
  • $\begingroup$ @Karl Thanks, do you know much about the cadmium sulfide and cadmium selenide? $\endgroup$ – iliar Mar 8 at 22:29
  • 1
    $\begingroup$ de.wikipedia.org/wiki/Cadmiumfarben (German is not so hard, give it a try.) The gist is that modern Cd colours are not simply CdS and CdSe, but mixed crystals thereof also containing zinc, and they are even less soluble than the originals. Their are still banned from construction use, only for art. $\endgroup$ – Karl Mar 9 at 20:37
0
$\begingroup$

I found an answer to my question. Typically oil paint manufacturers will write what pigments are used in their paints. The pigments are classified according to the 'color index' or C.I. These pigments may actually have different chemical composition, but nevertheless the color index can be used to search the pigment database here: http://www.artiscreation.com/red.html

For example, PR106 stands for genuine Vermillion, which is true Cinnabar and has a toxicity rating of C according to the table linked above, where A is non-toxic and D is extremely toxic.

Most colors that are marketed as 'cinnabar' are actually composed of various different pigments, most often not actually containing mercury.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.