A very toxic pigment that contains both lead and chromate. A carcinogen. Once when I met a chemist at an art demo and mentioned chrome yellow, his eyes widened and his eyebrows leapt up and he warned me of its extreme toxicity due to Chromium IV/ hexavalent chromium. See also the Artist's Guide to Health and Safety for information about the hazards of pigments containing Lead and also pigments containing Chrome.
Besides this there are other reasons to wonder about this color as it is known to darken- though modern means of manufacture (coating in silica) are said to help to mitigate this somewhat by coating the particle. Of the two modern paints we've tried they had masstones similar to colors in the cadmium yellows, though they did mix differently than cadmiums. Of the two we've tried, the primrose variety showed some color shift, possibly due to the sample we made having been later stored in the dark. We have heard of differences in manufacture that can mitigate darkening somewhat, however that goes beyond the scope of this article, and we feel the drawbacks outweigh any benefit. Please treat this pigment with extreme caution.
Our experience with this pigment tends to be a slow drier, though we have read that it is a fast drier in other places, so it is not clear what gave rise to that difference.
We recently learned from an older manuscript that these toxic chrome yellows used to be used to adulterate more expensive cadmium yellows. So be aware that they may be hanging out undisclosed in old tubes of paint. They were also used to give a little boost to ochres, a trend that Rublev nods toward in their Chrome Ochre blend, which shows an awareness of this chrome-ochre convenience blend. We mention this as the health hazard of a chrome yellow may not have been disclosed on old tubes of yellow ochre, nor on old tubes of cadmium yellow. People may not realize how toxic these could be.
