Hubert and Jan van Eyck’s masterpiece The Three Marys at the Tomb is almost 600 years old. What has happened to the paint over all that time? This is precisely the question being asked by researchers in the Paint Alterations in Time (PAinT) research project, which recently kicked off at the University of Amsterdam (UvA).
While an old oil painting may have all the appearance of a static object, in fact there is still a lot going on at the molecular level. Chemically and physically, old oil paintings are actually highly complex systems, being made up of various ground and paint layers, each with their own composition. Over the years, these systems age. Due to chemical reactions that are still largely unexplained, these paintings can develop unsightly deposits, discolourations or considerably greater transparency.
The PAinT researchers, led by Katrien Keune and Annelies van Loon of the UvA, want to gain a better understanding of the chemistry of oil paintings – including works by the Old Masters – in order to develop improved restoration and more enduring conservation techniques. To do this, they first had to build some basic knowledge about paintings that have been affected by ageing. They studied the different components that evolve in paint (binding agents, pigments and metallic drying agents) over time. All these ‘new’ components have an enormous influence on a painting’s optical qualities and stability.
The problem with changes in old paintings is that only the end result of these reactions, which can be appalling, is visible. We can only guess at the processes that have played out over the centuries. The PAinT team has come up with an innovative method for tackling this problem, by using chemical and mathematical modelling systems with the same basic characteristics as real layers of oil paint. These are subjected to an array of tests to simulate the ageing process and examine the influence of pigment type, solvents, heat and moisture on the progression of the reactions.
The team will be using this technique to study a number of paintings in Dutch collections. Among them are The Three Marys at the Tomb by Jan and Hubert van Eyck, Frans Hals’ regents’ portraits, several masterpieces by Rembrandt, Vermeer and Van Gogh, the Amsterdam town hall paintings by Jacob Jordaens and two early paintings by Piet Mondriaan.
The PAinT research project brings together chemists, restorers and art historians. Over the next few years, they will be working together to identify the basic degradation processes in the paint layers of old masterpieces. Katrien Keune and Annelies van Loon of the UvA are leading the project in collaboration with Utrecht University, six major museums in the Netherlands and various national and international partners. The research is part of the Science4Arts programme of the Netherlands Organisation for Scientific Research (NWO).