The mystery of using egg yolk as binders has finally been unravelled
Are you a painter? If yes, you may know how delicate and short-lived oil paintings can be, as they can wrinkle, turn yellow and get damaged easily. Maybe that is why Renaissance painters such as Leonardo da Vinci, Rembrandt and Sandro Botticelli used proteins such as egg yolk with their oil paints to make them durable.
This has recently been revealed by Dr. Patrick Dietemann of Germany’s Doerner Institute, Ophélie Ranquet of the Institute of Mechanical Process Engineering and Mechanics at Germany’s Karlsruhe Institute of Technology and University of Pisa’s (Italy) Dr. Ilaria Bonaduce. The duo found that the egg yolk acted as a catalyst to modify and fine-tune the quality of oil paints. Guess how they came to this conclusion? They developed three varieties of paint and analysed them. The first had a chemical mixed with linseed oil, the second had a few drops of egg yolk added to the oil and the last mixture contained a solution of diluted egg yolk after being dried, crushed and thrown into the oil. They soon figured that the final combination made a painting most rigid, thanks to the most amount of egg yolk used in it, followed by the second kind; while the first one showed no rigidity. In fact, they have also concluded that a same painting but with two separate ingredients can not only have different lasting periods, but also distinct microstructures and other fine attributes. What else, oil and egg yolk together gives a painting more intense and smooth colour transition, are less susceptible to darkening and are hardly affected due to extreme light exposure; not to forget egg yolk acts as a super antioxidant.
This study has been published in the scientific journal Nature Communications and has finally unravelled the mystery of why former painters preferred egg yolk as binders. In fact, the addition of the yolk, as per the experts, can reduce wrinkling, yellowness as well as moisture issues.
If you look through art history, you can find that even before Renaissance, painters used egg as a binding agent for their paintings. In fact, in the medieval times, there even existed a kind of paint called egg tempera (mixture of egg yolk, powdered pigments and water pioneered by ancient Egyptians). It can be found in fresco murals, such as the ones exhibited in Italy’s Palace of Nestor which can be traced back to 1200 BC. But later, in the 15th century, egg was replaced by oil and was largely used by Dutch painters such as Jan van Eyck. However, it was during the Renaissance that maestros like Vinci and Botticelli realised that a combination of dried yolk and oil did the best job. Why? Because, they were both rich in proteins, which are known for being natural binders. In fact, the latter’s Lamentation Over the Dead Christ is one of the best examples in this regard.
Researchers have also proven that one of the most popular kind of paints had the four vital ingredients, namely: dried egg yolk, distilled water, linseed oil and some kind of pigment. Incidentally, these worked best with lead white and ultramarine blue colours. In fact, lead white which is usually quite sensitive to moisture can become more resistant to it if a protein such as egg yolk is added.