There are things in life no one can escape from. Gray hair and wrinkles are typical aging phenomena. Many people use creams or other means to try to prevent or delay this process. Once you have wrinkles, there is always plastic surgery to pull the skin back tight in an attempt to undo the aging process.
The time patina also has big impact on the paintings of our master painters. Art restorers try to overcome these effects in a natural way.
Since the 15th century, oil paint is a widely used medium in painting. The main components of oil paint are pigment and binder. Pigment is a colored powder that gives the paint its typical color. As a binder, usually a vegetable drying oil is used, often linseed oil. Oxidation of the oil causes the drying and hardening of the paint. Oil paint has a long drying time. With thick paint, this may take several years. The drying time depends on many factors, such as oil type, thickness of paint, temperature, light as well as the pigment used.
In oil paint, the pigments are completely covered by the oil, which always gives the layers a degree of transparency even if the pigment concentration is quite high. As long as the oil paint has not dried yet, this also makes it possible to make changes that naturally mix with the already applied paint layer. Until the 19th century, oil paint was self-made by painters by grinding pigment and adding binder. Since then, paint is also available in tubes.
The reflection value is a value that expresses how light is reflected on a solid surface. This determines how we perceive a color. Different factors can affect the paint. The main factors are exposure to light and humidity. Therefore, climate control in a museum is also vital for conservation of the paintings. Possible effect can be that the transparency or the pigment composition changes and hence the reflection value. The visual effect is that the colors of the painting change. The time patina also influences paintings.
Effect on paintings
Poor quality paint tends to have an unstable composition and thus gives a color difference with the original paint over the years. Artists are usually not occupied with how their artwork will look over 100 years. Additionally, in their lives painters are often unknown and poor and not aware of paint quality effects.
An art restorer will always use the best quality paint in retouching paintings. In this way, the color difference will be as minimal as possible both now as in the future. In addition, in the restoration of masterpieces, the paint used in restoration will be given the same time patina as the original paint. In this way, the restoration will develop in the same way as the original paint over time.
A beautiful example of time patina is in the work of Velazquez, a Spanish master painter from the 17th century. Over the years, the reflection value of each paint layer has changed in its own way, such that an underlying paint layer has become visible. The fascinating is that it also reveals the artist’s intellectual process and intentions.
Clearly visible that the artist previously positioned the hind legs of the horse at another place.
On the left picture, the position of the gourd changed. At the right, it’s clearly visible that at first the left hand and leg were positioned differently.
This phenomenon is known as “Los Arrepentimientos de Velazquez” or “the regret of Velazquez”, referring to the changes that Velasquez mate at a later stage compared to the earlier sketches.
Antonio Ortiz Gacto
Antonio Ortiz Esteller (AOG) is an artist from the south of Spain with an own style. As an architect his characteristic buildings shape the landscape of Almeria. As a painter and drawer his legacy includes a portfolio of over 600 art works. Below a painting that also reveals a clear time patina:
The painting has been in a humid room for a long time. The humidity had a different effect on each layer of paint. As a consequence, an underlying paint layer has become clearly visible. The uniqueness of this effect is that both paint layers now seem to form an integrated composition and as such a new artwork is created – although not how it was intended by the artist.
Vincent van Gogh
The paintings by Vincent van Gogh and some of his contemporaries are also subject to changes. Where masters like Rembrandt manufactured their oil paint themselves, Van Gogh used tubes of paint. Advantage of the paint tubes is that it makes it much easier to paint outdoors. However, the quality of the tubes of paint was very poor in those early years, explaining the vulnerability of these paintings.
The color red is the most vulnerable one in the paintings of Vincent van Gogh. Red is slowly disappearing by the reactions in the paint under the influence of light. The following example highlights the painting “bedroom” from the Van Gogh Museum.
In the middle you can see how the painting looks now. The left shows a reconstruction of how it looked like in the past when Van Gogh painted it. On the right how the painting is likely to look in the future. The warm colors make place for a cool look.
To chart the decay in the Van Gogh paintings, scientific research is carried out. Sometimes the original pigments can be found underneath the frame and in places where the paint layers are thick. This gives an idea of how the aging process progresses. Also, research is done on how to copy the original paint used by Van Gogh and reproduce the aging process. With use of mathematical models, the original look of the paintings can be reconstructed.
The video below provides a comprehensive view of the scientific research and the discoloration of the paintings by Vincent van Gogh.
With this knowledge, it is theoretically possible to restore the paintings to its original colors as closely as possible. However, it has not been chosen to carry out such rigorous restoration. The art restorer should then also have to color retouch original strokes of Vincent van Gogh. As such we would lose more than we would win. Making such considerations once again indicates that restoration is more than just applying a number of techniques. See also my previous blog about the ethics of painting restoration.
The developed mathematical models also allow to predict how the paintings will look like in the future. The results are confrontational. All the red will disappear. Leaving little of the original warm colors as intended by Vincent van Gogh.
Further research is needed to help develop techniques that can prevent further decay. In the future, new restoration techniques may be available that can counteract decay. This endorses why a painting restoration must always be reversible. A first short-term measure that has been taken is the reduction of the light levels in the Van Gogh museum.