I am currently rereading David Hockney’s Secret Knowledge
Contrary to the accusations of his opponents he doesn’t suggest that all, or even most, artists were copying projected images. These critics hotly deny that the “Old Masters” would have needed any assistance and were more than capable of drawing realistically without optical aids but I don’t think that is his point. Although it is in fact perfectly possible (though darned difficult) to create photo-realistic images by eye alone, nobody actually did so until the Dutch introduced a startlingly different style of painting, quite suddenly, in the early 15th century.
Starting with van Eyck, the style of rendering, especially the human figure, but also still life, changed within a remarkably short span of years. It wouldn’t have been necessary for all artists to be using lenses and mirrors as artists have always learned by copying their masters. When the masters learned by copying a two dimensional projected image, a whole new style of drawing was born and this style would have been copied by those who came after.
His thesis fascinates me despite the fact that it is often dismissed as a crackpot theory and he is in fact vilified by some of his detractors. It is obviously a very emotional issue for some people who find it necessary to make highly personal attacks on Mr. Hockney in order to refute his theories. Actually I got the impression that some of his critics had not in fact read the book, or only skimmed it very superficially. This is unfortunate because it isn’t actually very long. I have always been attracted to controversial theories and I think that Mr. Hockney makes some excellent points. This book is definitely worth a read and it is so lushly illustrated that I felt the need to add it to my collection.