In the late 1880s, Vincent van Gogh began to paint gorgeous, bright yellow sunflowers. However, even before the artist passed away, his paintings were beginning to dull.

For years the reason behind the discoloration had puzzled scientists. But with new technology, scientists believe they now know what happened to the bright color.

Discoloration: A Process

When paintings change color, it is usually because of adverse conditions. In the summer, the paintings heat up and react to the changes in temperature. Air-conditioning units help to slow the process.

The reason scientists were so puzzled in van Gogh's case was because some paintings that used yellow turned brown while others remained unaffected. The paintings that changed color the most had been lightened using white pigments.

Chemistry At Work

So, what started the color-changing process? Well, researchers found that sunlight started the chemical reaction. Sunlight oxidizes with the oil-based paint. This process releases electrons.

The electrons are grabbed up by the vibrant, yellow paint which created a green color. Lastly, the green paint mixed with oxidized oil and produced the dull, brown color.

Read More:

• Van Gogh doomed his sunflowers by adding white pigments to yellow paint (The Guardian)