Scientists have discovered that the bright-yellow pigment featured in several famous artworks becomes unstable under LED lights and, over time, turns a shade of brownish green. A sample of 14 works from the period between 1887 and 1890 were tested for the reaction which affects the oil paint colour known as chrome yellow. It was favoured by 19th-century artists and has been found in important works by Paul Cézanne and Paul Gauguin.

Researchers have now warned galleries and museums to reconsider the use of some LED lighting to prevent the colours in such paintings deteriorating further.

Claus Habfast, from the European Synchrotron Radiation Facility in France, where some of the artworks were studied, said: "LED lights appear to have many advantages but museums should carefully consider that paintings from the Van Gogh era could be affected by them.

"Paintings that have moderate darkening will find this accelerates in the coming years.