Giovanni di Paolo_ The Metropolitan Museum of Art Bulletin, v. 46 ..

but about I440 it reappears in the background of a
Madonna of Humility in the Museum of Fine Arts, Boston,
which is covered with diagonal incisions broken up with
horizontal lines, producing a number of rhomboid fields
differentiated from each other by their crops (figs. 28, 30).
There is no system of diminution, and it is distance, not
degrees of distance, that is shown. Not till the I450S was
this technique developed to the point at which we see it in
the scenes from the life of the Baptist. The decorative principle
throughout these panels is uniform; it consists of
consecutive horizontal lines parallel to the base of the panel
cut sharply by diagonal lines at angles of between ten and
forty-five degrees. The effect is a peculiar one; it carries the
mind out beyond the confines of the picture space. It is
anybody's guess whether it was intended to do that, or
whether it was thought of as no more than a means of
imposing visual coherence on the scene.
Simpler and less decorative than Giovanni di Paolo's
scenes from the life of the Baptist are his ten scenes from
the life of Saint Catherine of Siena, three of which are
29. Detail of the London Baptist Entering the Wilderness, figure 21
30. Detail of figure 28 23