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"Van Gogh paintings 'degraded by UV-driven  reaction'"
February 14

 

Scientists have identified why the bright yellows  in some of Vincent van Gogh's paintings have turned brown. A complex chemical  reaction is behind the deterioration of the works. The finding is a first step  to understanding how to stop some of the Dutch master's most famous paintings  from fading over time. The results, published in the journal Analytical  Chemistry, suggest shielding the affected paintings as much as possible  from UV and sunlight. Sunlight can penetrate only a few micrometres into the  paint, but over this short distance, the researchers found it could trigger a  hitherto unknown chemical reaction turning chrome yellow into brown pigments,  altering the original composition. The scientists employed a microscopic X-ray  beam to reveal a complex chemical reaction taking place in the incredibly thin  layer where the paint meets the varnish.