The design for the vermilion cloth
of honor behind the Virgin and Child was created using a technique
called sgraffito, which is an Italian word meaning scratched. In
this case silver leaf was laid over moistened red bole, and once
dried the leaf was burnished with a smooth pebble or a hound's tooth,
as recommended by Cennino Cennini, a late fourteenth century artist
and compiler of artist's techniques. Then the silver leaf was completely
covered with vermilion egg tempera paint that was probably modeled
in the shadows with a semi-transparent red lake, similar to madder.
The artist then took a pointed stick or bone and carefully scratched
a design in the paint down to the silver leaf. The design in this
instance probably represents a pomegranate. While some designs were
drawn by hand, as was the one in this painting, others were transferred
using a cartoon or template.