Multispectral digitization is demonstrated at the Palais des Beaux-Arts de Lille


1. Vanity by Jan Sanders van Hemessen at the Musée
des Beaux-Arts de Lille being digitized
Photo : Musée des Beaux-Arts de Lille and Lumière Technology

We met the director of Lumière Technology, Jean Pénicaut a few months ago. The photographic process marketed by this company struck us as being absolutely revolutionary.

During the Journées Européennes du Patrimoine (European Heritage Days) last weekend, Alain Tapié, director of the Palais des Beaux-Arts de Lille invited him to demonstrate this multispectral digitizing system. Seven paintings from the collection were photographed (ill. 1) with this process shown to the public for the first time in a French museum [1]. During the two days of the Heritage Days, museum goers discovered the extraordinary possibilities which this technique offers for reproducing and studying paintings. In one photo session lasting barely an hour, a painting is photographed in 240 million pixel definition, by splitting the light spectre from ultra-violets to infra-reds. The results, which can be printed or viewed on a high-definition screen, is amazing. It provides specialists, conservators or restorers with a considerable number of basic information.

2. Comparison between Christ Blessing the Virgin
from the Former Southern Low-Countries, XVIth C.
(Lille, Musée des Beaux-Arts)
and a copy of its digital image by Lumière Technology
Photo : D. Rykner

Let us remember that the color of a painting depends on the pigments and the light which falls on it. The technology used here provides a reproduction with the colors being exactly those of a painting under a certain light (ill. 2). Since the pigments used for photographs are different than those used by the artist, when the light changes, the colors may not correspond to those of the original. The goal, eventually, is to create a printer using pigments that react in the same way as old ones do, thus producing reproductions which are identical to the original no matter what the light. The results today are already exceptional. With this technology, Federico Zeri would never have preferred black and white.

Detail of the head of the Virgin in the
painting Christ Blessing the Virgin as digitized by
Lumière Technology (natural color) showing the use of a minute
touch of a certain blue pigment in the eyes, not noticeable otherwise
Photo : D. Rykner

But these are not the only advantages. The 240 million pixel definition shows the slightest detail (ill. 3), some of which are invisible to the naked eye, not only in a natural color, but also under infra-reds, ultra-violets, false or inverted false colors, even when simulating a lighter varnish. Without going into complicated technical explanations, this means that the same painting can be seen under different aspects allowing specialists to analyze in-depth the manner in which it is painted or to see what is hidden under the painted layers. Even better, the pigments used in the painting can be identified at any given spot on the canvas, without having to take a sample, thanks to the spectral information contained in the length of their light waves. Lastly, the digitized photographs of the paintings, in identical light conditions, can be compared as if working with the originals themselves. The images become a perfectly exact measuring tool. The interest of this technique for an art historian is obvious, especially when the complete works of an artist are available in this way.

Lumière Technology has already photographed several Van Goghs at the Musée Kroller Muller in Otterlo and will go to the Van Gogh Museum in Amsterdam in October. The latter would like to have mathematicians and physicists study the artist’s brush strokes (orientation, length, manner in which he ends his gesture…) This technology can help them to do so. Among some of the results on Van Gogh, we would like to point out a discovery on a canvas at the Kroller-Muller : some brush strokes which appear to be of the same green color are in fact executed with very different pigments. Let us imagine that this characteristic — unknown to copiers since the naked eye only sees identical colors — is found in other paintings, it would provide to specialists vital evidence of its authenticity.


After Hans Holbein the Younger (1497-1543)
Portrait of the painter’s family
Oil on vellum maroufled on panel - 89 x 63 cm
Lille, Musée des Beaux-Arts
On the left, present state of the painting
(only one child has varnish taken off)
On the right,
simulation thanks to multispectral digitization of the whole
painting without varnish
Photo : Musée des Beaux-Arts de Lille
and Lumière Technology

Alain Tapié, Director of the Palais des
Beaux-Arts explaining the
false colors in the painting and the underlying drawings to
the audience
during the Heritage Days
Photo : Musée des Beaux-Arts de Lille
and Lumière Technology


Among the works photographed in Lille [2], there is a painting which is today considered to be a copy after a Holbein held in Basel (ill. 4). A lightening of the varnish had already been undertaken by William Whitney, maître de conference at Paris Sorbonne I, who directs a seminar of applied technology in art studies at C2RMF (Louvre), on the figure of the child on the right, but it had not been finished [3]. The multispectral photograph and the analysis of the pigments and the varnish enabled Lumière Technology to simulate a virtual cleaning of the painting and produce an image of what the work might look like after a complete restoration. Moreover, musical notes and gothic characters not revealed as clearly earlier with x-rays were discovered on the support. According to William Whitney who commented on this painting for the audience : “This technology does not replace our work of restorer-conservator. But it seems essential in preparing a restoration. Hasty or radical decisions can thus be avoided, even when suggested by certain laboratories, such as taking all the varnish off at once instead of proceeding layer by layer…as in archaeology. It will be easier to identify each layer of varnish and choose the right solvent, taking whatever time is needed [4]”. As for Alan Tapié, who was very enthusiastic (ill. 5), he insisted during the press conference on the non-intrusive aspect of the method, which helps the restorer to make a decision : “By penetrating the painting electronically and not physically, it is not touched, and cannot be damaged. The painting will only be handled if required.”

Progressively, large museums are realizing the radical innovation of the system invented by Pascal Cotte who founded Lumière Technology and all its possible applications. Recently, the team travelled to Cracow to photograph the Lady with an Ermine. Eventually, the company would like to create the largest possible database providing art historians with an incomparable work tool and museum goers a new source of knowledge.

Palais des Beaux-Arts Website

Lumière Technology Website


Didier Rykner, samedi 22 septembre 2007


Notes

[1] With the exception of the Mona Lisa which was digitized in 2004 at the C2RMF

[2] The seven paintings that were photographed are :
- Former Southern Low-Countries, early XVIth C., Christ Blessing the Virgin, Oil on wood, State Deposit, 1946 / Inv. P 1726.
- Biagio d’Antonio, The Virgin in Adoration of the Child Jesus, Oil on wood, Inv. P 791.
- Hans Holbein the Younger (after), Portrait of the Painter’s Family, Oil on vellum marouflé on wood, Inv. P 191.
- Jan Sanders Van Hemessen, Vanity, Oil on wood, Inv. P 2009.
- Pierre Paul Rubens (after), Prometheus Chained, Oil on wood, Inv. P 115.
- François Boucher (attributed to), Allegory of Painting, Oil on canvas, P 342.
- Jacques-Louis David, The Fight between Minerva and Mars, Oil on canvas, P 1983.

[3] According to Florence Gombert, conservator at the Palais des Beaux-Arts for the Antiquities, Middle-Ages and Renaissance department, it is not impossible that this painting might be revealed as being in fact an authentic Holbein.

[4] Statement recorded during the video shot at the Palais des Beaux-Arts de Lille during the Heritage Days



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