(CN) — State-of-the-art imaging techniques and algorithms have allowed a team of scientists and art experts to peer beneath the layers of restorations covering a Renaissance masterpiece in a Belgian cathedral.
The Ghent Altarpiece is among the world’s pre-eminent examples of western art, up there with the “Mona Lisa” and Michelangelo’s David. Completed over the course of nearly a decade from the mid-1420s to 1432, the gem of St. Bavo’s Cathedral has undergone numerous restorations over the past six centuries. Cultural heritage scientists have been trying to unravel those changes to show the original work as intended by artists Hubert and Jan van Eyck, and they describe their efforts in a study released Wednesday in the journal Science Advances.
The polyptych, also known as “The Adoration of the Mystic Lamb,” is made up of an 11-foot-by-15-foot set of wood panels comprised of 12 interior panels, each displaying a portion of a biblical scene culminating in the slaughter of the lamb of God. The canvas is typical of an early Netherlandish panel painting. First, an artist would coat a wood panel with a base layer mixture of chalk and glue. They would then sketch an outline of the planned image over the base layer and seal it with translucent primer composed of oil and pigments. After the final detailing stage, the artist had to wait a full year for the paint to dry completely before finishing the piece with a varnish to saturate the colors.
A team led by Dr. Geert Van der Snickt of the University of Antwerp in Belgium employed a variety of techniques such as high-resolution color photography, X-rays, infrared imaging, paint sample analysis and cutting-edge chemical imaging, among others, to unlock the long-buried secrets.
“During the first phase we found that large areas on the reverse side of the wings were overpainted in the 16th century,” Van der Snickt said in an email. “At the start of the second phase, conservators soon noticed that this was also the case for the front side. By combining two innovative chemical imaging techniques we were able to objectively confirm this visual observation and, moreover, visualize how the artists built up their composition layer by layer, starting with the first sketch (underdrawing) and ending with the overpaints.”
Van der Snickt said the team was able to determine that the original lamb, the focal point of the piece, was originally smaller, with a sagging back, a more rounded hindquarter and a smaller tail. Its eyes, nose and ears had also been repositioned, implying that the face of the Eyckian lamb must have been quite different. The result after removing multiple layers of overpaint surprised the team, revealing a lamb with eyes positioned unnaturally toward the center of its face, appearing with an almost human expression and staring directly into the viewer’s eyes.
Past restorations lacked the technique — and technology — necessary to return the piece to its original form. The most recent restoration took place in the 1950s, however due to a lack of time and tools those involved refrained from removing the overpaint on the lamb itself, leading to a four-eared lamb for the next 70 years. Experts now believe viewers are seeing the original design for the first time in four hundred years.
“There is no doubt that, what we see now after the overpaint removal, is the original painting by Van Eyck. There are simply no other artists that could have obtained that kind of brushwork,” Van der Snickt said.
The Ghent Altarpiece has experienced a particularly turbulent history. The piece made its way to Germany in 1821 when it was purchased by the King Frederick William III of Prussia. Nearly a century later it was returned to Belgium as part of a compensation package mandated by the Treaty of Versailles following World War I. Not to be dissuaded, Adolf Hitler ordered the painting’s seizure and had it hid in a German salt mine for the course of World War II, where it sustained significant damage. Following the Allied victory, the piece once again made its way back to Ghent where it stands today.
Two questions remain of the artists’ original intentions, according to Van der Snickt.
“First, why did the Van Eycks paint the face of the lamb in this peculiar way? That is an aspect that can only be explained by art historical scholars,” he said.
“Second, we found that the hindquarters of the earliest version was more rounded, while this looks now more squared. Was this a change made by the Van Eycks? A so-called pentimenti?” he continued, referring to the term for visible traces of earlier painting beneath a layer of paint on a canvas. “Or was it a change that was part of a very early conservation treatment, which took place before the large scale 16th century overpaint campaign? We do not know, so that part was left untouched by the conservators.”