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ART AND SCIENCE: Vincent Van Gogh and His Fading Flowers
Locally, the Arizona desert has come into bloom with an array of flowers often so brilliantly colored and showy they look like they've been pasted on. In the wash adjacent to my home studio, the bright yellow flowers of the brittlebush offer a pleasant, albeit temporary color display. The brittlebush flowers are short-lived and will fade and drop soon. The plant then dries to its namesake and waits for the next rainy season.
Fading colors have presented a challenge for painters for millennia. Up until the 19th century artists mixed their own pigments by hand and doing so required an extensive knowledge of toxicity, stability and chemical reactivity. Certain colors could not be mixed or even placed next to each other in the painting as discoloration would occur due to their chemical reactivity with one another and with the environment.
One color missing from the painter's pallet up to the mid 18th century was a vibrant yellow pigment. This was to change with the chance discovery of a scarlet-orange mineral deep in a Siberian gold mine. The mineral, named crocolite, contained the yet unknown element chromium, the salts of which could produce an extraordinary range of hues. Lead chromate for example, could range in color from lemon yellow to a beautiful deep red depending on how it was manufactured. The French chemist who had made these discoveries thought they would make delightful painter's pigments and by 1809 they were on artist's palettes.
Which brings us to Vincent van Gogh. Van Gogh was especially enamoured with this new vibrant yellow. His series of sunflower paintings begun in 1888 made heavy use of the chrome yellow pigment. Unfortunately, what was unknown to van Gogh was that chrome yellow reacts with other pigments in the presence of sunlight and can darken over time. Sadly for artists and art lovers alike his beautiful sunflowers have turned brown with age. A bit like the brittlebush, whose sunny yellow flowers need to be enjoyed in their moment.
