Chrome green
Not a pigment but a ready-made mixture — chrome yellow and Prussian blue, ground together and sold in a tube. Chrome green is a commercial convenience that became a period style, and it carries the weaknesses of both its parents.
Origin
Once chrome yellow became cheap in the 1810s and Prussian blue was already cheap, colourmen began premixing the two, since the combination gives a strong, opaque, mid-range green far more powerful than green earth and far safer to sell than emerald green. It was marketed under many names — chrome green, cinnabar green, Brunswick green, milori green — with the proportions varying between manufacturers and often between batches, so no two chrome greens are quite alike. It was primarily a commercial and decorative paint, sold in vast quantities for coaches, shutters, railings and house painting, and reached the artists' range as a by-product of that trade.
In art history
It appears in eight eras here, concentrated in the nineteenth century and the early twentieth. Landscape painters used it for foliage, where its opacity and strength cover ground quickly, and it is the green of a great deal of academic and commercial painting from the period — the green of respectable nineteenth-century trees. More interestingly, it is the green of the painted world outside the studio: the shutters, wagons, park benches and shopfronts of the nineteenth-century city were chrome green, and its particular slightly dead mid-tone is one of the colours that dates a period photograph the moment it is colourised.
In the studio
Being a mixture, it inherits both problems. The chrome yellow component darkens over time as lead chromate reduces, and the Prussian blue component is destroyed by alkali and shows reversible light-fading. The two failing at different rates in different conditions means chrome green passages can shift noticeably in hue as they age, usually towards blue as the yellow degrades, and this is visible in nineteenth-century paintings where foliage has cooled from a warm mid-green towards something colder and greyer. It is also toxic from the lead chromate. It handles well: opaque, strong, fast-drying and easy.
Afterlife
Regulation of lead chromate and the availability of phthalocyanine green have removed it entirely. Modern tubes labelled chrome green contain phthalo mixtures with no chromium in them at all. Its only current relevance is diagnostic — finding it in a painting places the work after about 1810 and, if the hue has shifted, tells a conservator exactly what has happened.
Where it appears
Every era and artist in this atlas whose palette includes this pigment.