“Outdated Masters” resembling Leonardo da Vinci, Sandro Botticelli and Rembrandt might have used proteins, particularly egg yolk, of their oil work, based on a brand new examine.
“There are only a few written sources about this and no scientific work has been completed earlier than to research the topic in such depth,” mentioned examine creator Ophélie Ranquet of the Institute of Mechanical Course of Engineering and Mechanics on the Karlsruhe Institute of Know-how in Germany, in a cellphone interview. “Our outcomes present that even with a really small quantity of egg yolk, you’ll be able to obtain an incredible change of properties within the oil paint, demonstrating the way it might need been helpful for the artists.”
Merely including some egg yolk to their works, it seems, may have long-lasting results that went past simply aesthetics.
Eggs vs. oil
In contrast with the medium formulated by historical Egyptians known as tempera — which mixes egg yolk with powdered pigments and water — oil paint creates extra intense colours, permits for very clean coloration transitions and dries far much less rapidly, so it may be used for a number of days after its preparation. Nonetheless, oil paint, which makes use of linseed or safflower oil as an alternative of water, additionally has drawbacks, together with being extra prone to paint darkening and injury brought on by publicity to mild.
“The addition of egg yolk is helpful as a result of it may well tune the properties of those paints in a drastic method,” Ranquet mentioned, “For instance by displaying growing older otherwise: It takes an extended time for the paint to oxidize, due to the antioxidants contained within the yolk.”
The chemical reactions between the oil, the pigment and the proteins within the yolk immediately have an effect on the paint’s conduct and viscosity. “For instance, the lead white pigment is sort of delicate to humidity, however in case you coat it with a protein layer, it makes it much more immune to it, making the paint fairly straightforward to use,” Ranquet mentioned.
“However, in case you needed one thing stiffer with out having so as to add numerous pigment, with a little bit of egg yolk you’ll be able to create a excessive impasto paint,” she added, referring to a portray method the place the paint is specified by a stroke thick sufficient that the brushstrokes are nonetheless seen. Utilizing much less pigment would have been fascinating centuries in the past, when sure pigments — resembling lapis lazuli, which was used to make ultramarine blue — have been costlier than gold, based on Ranquet.
“The Madonna of the Carnation,” on show on the Alte Pinakothek in Munich, Germany, is certainly one of Leonardo da Vinci’s earliest work. Wrinkling of the oil paint is clear on the faces. Credit score: DeAgostini/Getty Photographs
A direct proof of the impact of egg yolk in oil paint, or lack thereof, might be seen in Leonardo da Vinci’s “Madonna of the Carnation,” one of many work noticed in the course of the examine. At present on show on the Alte Pinakothek in Munich, Germany, the work reveals evident wrinkling on the face of Mary and the kid.
“Oil paint begins to dry from the floor down, which is why it wrinkles,” Ranquet mentioned.
One cause for wrinkling could also be an inadequate amount of pigments within the paint, and the examine has proven that this impact might be averted with the addition of egg yolk: “That is fairly wonderful as a result of you have got the same amount of pigment in your paint, however the presence of the egg yolk modifications every part.”
As a result of wrinkling happens inside days, it is probably that Leonardo and different Outdated Masters might need caught onto this explicit impact, in addition to further helpful properties of egg yolk in oil paint, together with resistance to humidity. The “Madonna of Carnation” is certainly one of Leonardo’s earliest work, created at a time when he might need been nonetheless making an attempt to grasp the then newly common medium of oil paint.
New understanding of the classics
One other portray noticed in the course of the examine was “The Lamentation Over the Lifeless Christ,” by Botticelli, additionally on show on the Alte Pinakothek. The work is generally made with tempera, however oil paint has been used for the background and a few secondary components.
“We knew that some elements of the work present brushstrokes which might be typical for what we name an oil portray, and but we detected the presence of proteins,” Ranquet mentioned. “As a result of it is a very small amount and they’re troublesome to detect, this is likely to be dismissed as contamination: In workshops, artists used many alternative issues, and possibly the eggs have been simply from the tempera.”
Nonetheless, as a result of including egg yolk had such fascinating results on oil paint, the presence of proteins within the work is likely to be a sign of deliberate use as an alternative, the examine prompt. Ranquet hopes that these preliminary findings may entice extra curiosity towards this understudied matter.
Maria Perla Colombini, a professor of analytical chemistry on the College of Pisa in Italy, who was not concerned within the examine, agreed. “This thrilling paper gives a brand new state of affairs for the understanding of previous portray strategies,” she mentioned in an e-mail.
“The analysis group, reporting outcomes from molecular degree as much as a macroscopic scale, contributes to a brand new information in using egg yolk and oil binders. They aren’t extra taking a look at merely figuring out the supplies utilized by Outdated Masters however clarify how they might produce great and glittering results by using and mixing the few out there pure supplies. They attempt to uncover the secrets and techniques of previous recipes of which little or nothing is written,” she added.
“This new information contributes not solely to a greater conservation and preservation of artworks but in addition to a greater comprehension of artwork historical past.”
High picture: The “Mona Lisa” by Leonardo Da Vinci
