Members of the P. R. B. were not attempting to recreate the early Renaissance tradition, but they were inspired by the inner luminosity of glazes, such as in the wondrous green gown worn by Giovanni Arnolfini’ s bride. To achieve such effects they were scrupulous to apply their jewellike transparent colors over a bright white ground, which makes for a stained glass window effect, as seen for example, in the blue dress of the Mariana by Millais.
Although artists’ manuals abounded 6 during the 19th century, the precise medium used in Van Eyck’ s glazes was a mystery. In 1847 Charles Lock Eastlake, later first director of the National Gallery, published Materials for a History of Oil Painting, in which he pulled together as many ancient manuscript sources as he could, in order to trace the reason for the remarkable preservation of paintings over 400 years old. One of the most intriguing suppositions was that Van Eyck might have included amber varnish in his paint.
There is an understandable mystique to the idea that there was some“ secret” ingredient. A practical reason is that plain linseed oil turns glazes yellow and won’ t dry. Adding a resin to the oil makes sense because it can restrain the flow( rheology) of the oil and increase the depth of transparency and saturation of color. But how to prove this in Van Eyck?
After World War II, the Allies recovered the Ghent Altarpiece from Hitler’ s rape of the European cultural heritage. The Adoration of the Mystic Lamb has been called“ the most stolen painting in history.” After its recovery from a salt mine in Austria( popularized in the movie The Monuments Men( 2014), a collegium of experts was called to take careful stock of its condition, stabilize, and restore it. 40 ART CHOWDER MAGAZINE
Jan Van Eyck( before ca. 1390-1441) detail from the altarpiece The Adoration of the Mystic Lamb, central panel 1430-1432 St Bavo’ s Cathedral, Ghent, Belgium
One outcome of that project was the book L’ Agneau Mystique au Laboratoire, published in 1953 7, the first publication of a scientific study devoted to a single artwork and a landmark in the field of conservation science.
Through a series of microchemical analytical tests the team was able to identify, not only the pigments used by Van Eyck, but evidence of the binding media that held the pigment particles in place. The actual paint layers were predominantly oil, though in some areas something was added that wasn’ t a protein( e. g. egg or animal glue). Coremans’ s team called it“ drying oil +‘ x’”— possibly a natural resin.