Renaissance artists probably used egg yolks to protect their artwork. Scientists in a new study examining the artworks by “Leonardo da Vinci” and “Sandro Botticelli” found that they used this substance to protect their paintings from moisture and wrinkling.

Researchers have also found that famous Renaissance painters such as da Vinci and Botticelli probably used egg yolk in their oil paints to increase the resistance of their artworks. Some of the iconic works of the past are known to contain protein, but this new research suggests that the addition of eggs to these paintings was probably intentional.

Scientists say that adding eggs to oil paintings has an antioxidant-like effect that reduces signs of deterioration. However, there is very little written evidence about this. And there was no scientific study to investigate this case before.

“Our findings show that even with very little yolk you can achieve surprising changes in oil color,” the researchers claim. That is why artists probably used this method to make their artworks.

Egg yolk proteins prevent absorbing water in wet environments in paintings. This mechanism also prevented paintings from yellowing and wrinkling. Researchers say that even Leonardo da Vinci faced this problem. But this solution made their artworks last longer and we can see them even today.

One direct evidence of the effect of egg yolk in oil paints, or lack of use, can be found in the Madonna of the Carnation painting. In this painting, which is being kept in Germany, you can see the traces of wrinkles on the face of “Maryam” and her child. Madonna of the Carnation is one of Da Vinci’s first paintings, so he probably had not yet achieved the necessary mechanism to preserve paintings at the time of creation. The results of the current research are published in Nature Communication journal.