刘海燕

Scientists discover why red hues in Van Goghs paintings are slowly turning white.

If you were to compare Van Goghs painting Wheat Stack Under a Cloudy Sky today with how it looked when it was completed in 1889， you might notice a little difference. The fall leaves floating （漂浮） on the surface of the pond in the artwork arent as red as they once were. They now look more like something of the white clouds painted in the sky above.

Scientists recently found out what caused the color change. A pigment （颜料） the artist used to color his paints is slowly breaking down， turning from red to white.

Van Gogh used a red pigment called red lead， or minium （朱红）， in many of his paintings. Scientists have long known that minium whitens over time. But they didnt know why.

To learn what was causing the color change， researchers from the University of Antwerp in Belgium examined a very small paint sample （样品） taken from Wheat Stack Under a Cloudy Sky. They broke it with a focused beam （聚焦光束） of X-rays， a type of high-energy wave， to study its chemical composition. From the chemicals discovered， they determined that minium experiences a set of reactions when exposed （暴露） to sunlight and air， forming white crystals （水晶体） that have made the Van Gogh painting different.

The findings are important because understanding how pigments break down could help museums better know a paintings original （最初的） colors so they can be brought back to their conditions before. It could also help them better keep artworks in their original state， keeping paintings from becoming less bright in the future. Changing the environment in which paintings that have minium are kept， for example， could prevent the pigment from turning white.

The scientists work may explain why colors in other priceless Van Goghs paintings， like Sunflowers and The Bedroom， have lightened too. “Normally， the idea is these paintings are there for a hundred years， or five hundred years， and they appear the same—nothing really changes，” says Koen Janssens， who led the study. “But changes really take place when you look closely.”

閱读简答

1. What has happened to Goghs painting Wheat Stack Under a Cloudy Sky？

2. What has caused the change of color of the painting？

3. Why are the findings important？

4. Who is the leading scientist in the study？

答案：

1. It looks a little different now/ Its color has changed a little/Its color has become less bright.

2. The minium in the picture has experienced a set of reactions when exposed to sunlight and air， forming white crystals.

3. Because they can help museums better know a paintings original colors and keep artworks in their original state.

4. Koen Janssens.