|Portrait of a Man in a Turban,|
1433, Jan van Eyck
(possibly a self-portrait)
To understand what a tremendous discovery pigmented linseed oil (made from flax seeds) truly was it's necessary to come to grips with the clumsy ways and means painters had to contend with previous to this breakthrough. There was fresco, of course, which was something of an improvement in picture-making over mosaic wall murals, from which it derived. Frescoes were originally the poor-man's mosaic. However frescoes were not portable. A painting to hang on the wall was first a flat piece of wood (no small task in this pre-plywood era). After the planks were painstakingly planed, joined, and smoothed, they were covered with linen to which a mixture of plaster and rabbit skin glue was added (in several layers). The Italians called it gesso. This had to be sanded, smoothed, and polished (by apprentices) until it looked and felt like polished marble (and weighed, no doubt, almost as much). Over this was added an under painting of green or brown pigment to which was then added, layer after tedious layer of egg tempera, one of the most unforgiving painting mediums ever known to man.
Of course, I needn't recount canvas preparation or oil painting because we are all too familiar with that. Unlike the painters of Italy who descended from mosaic artist, the Flemish painters came from a long line of manuscript illustrators, which gave them a whole different approach to painting. Their painting style was tight, highly detailed, exquisitely jewel-like in overall effect. Their patented use of oils (the secret recipes were many and quite varied) allowed Flemish artists to explore photographic realism 400 years before photography was even invented. But the very portability that made oil painting so valuable also guaranteed that the news (indeed, the paintings themselves) would quickly spread first to Germany, then south to Italy where the Florentine artist Andrea del Castagno was accused of murdering his fellow artist, Domenico Veneziano (who had learned of this secret painting method) in order to keep it from becoming widespread in Florence and thus replacing his more traditional methods. In any case, van Eyck's "secret" remained so less than 40 years.