Jan van Eyck's understanding of perspective is not at all perfect. But his
artistry is great, so the fact is not obvious. If you trace the receding
lines in the Marriage of Arnolfini, you'll discover that the horizontals on
the window recede to one vanishing point, those on the floor recede to
another, and those on the ceiling recede to a third. Eyck knows that sets of
parallel lines on a plane recede to a point, but he doesn't know that all
parallel lines recede to the same point, even if they are on different
planes. Instinctively, he puts the vanishing point for the floor lower down,
that for the ceiling higher up, and that for the window in between the two.
The illusion still works, because the "error" is subtle, and there's a lot
else going on in the picture helping the illusion along. The same
misunderstanding is pervasive in pictures from that era, even though artists
are paying the utmost attention to correctness of perspective, it being
admired as proof of virtuosity. The pervasiveness of this misunderstanding
even among masters like Eyck, Bouts and Memlinc illustrates an interesting
fact, namely, that although modernists love to pooh-pooh perspective as a
simple trick that any school kid can learn, and as a merely arbitrary way of
presenting a picture, it took hundreds of years (from the beginning of the
14th century to the beginning of the 17th) for Europe's artists and
mathematicians to develop a complete understanding of how perspective works.
Like atoms and gravity and the roundness of the Earth, perspective is only
obvious when you know it.
