How to preserve priceless masterpieces
The chrome yellow pigment used by renowned post-Impressionist artist Vincent van Gogh and others in the 19th and 20th centuries is especially sensitive to certain types of light - making it extremely susceptible to darkening, according to a new study.
The finding could help preserve masterpieces by van Gogh and contemporaries like Gauguin, Cezanne and others.
In previous research, the scientists found that this alteration is at least partially due to a change in the oxidation state of the chromium in this type of pigment over time. In the current work, they wanted to determine the color change effects of shining different types of light on the yellow pigment.
They conducted laboratory tests with lab-made pigments that were similar in composition to pigments that van Gogh used, as well as a historical paint sample from Rik Wouters, a Belgian artist active in the late 1800s/early 1900s. Those chrome yellow paint samples that also are rich in sulfates were highly susceptible to browning, especially in regular, UV and blue light.
The researchers suggest that to prevent darkening, art collectors and gallery owners should minimize their paintings' exposure to light in the blue/violet/ultra-violet range.
The study has been published in ACS' journal Analytical Chemistry.