Figure 3. Infrared reJlectogram assembly of the Virgin's head (area of reJlectogram: 23 X 17 em).
Type II underdrawing characterized by variable density and line width. ReJlectograph by M. Faries.
can be seen in the cross section illustrated in Plate 29a, obtained from the
location marked in Figure 3. The underdrawing layer is only a few microns
thick.
Ty pe II underdrawing is characterized by variable line width and intensity.
These properties, together with the distinctly dropletlike fo rms visible in some
places, suggest type II lines were produced using a liquid. Type II lines are
fo und in the figural group of the center panel, where they describe the fo rms
more firmly. Figure 3 shows the infrared reflectogram of St. Anne's head.
Here sketchy type I lines have been overdrawn with the type II underdrawing.
Nearly all the underdrawing in the St. Anthony predella panels is executed
with a liquid type II drawing material that lays out the composition concisely.
In the central figural group of the main panel, however, the line is often rigid
and repetitive as, fo r example, in the shading to the right of the Christ Child.
In addition to these kinds of underdrawing there is a third fo rm, type III,
that can be seen with the naked eye in St. Anne's red robe (Fig. 4). These
lines are characterized by their bold appearance with handling qualities more
similar to that of a paint than of an ink. A cross section shows type III was
laid down thickly, and then covered with a translucent layer (Plate 29b). Ty pe
III has only been found in St. Anne's red drapery and no other place in either
the side or predella panels. A fo urth type of marking of fo rm is evident in
the reflectogram of the Virgin's sleeve (Fig. 5). Here, a dark irregular line lies
over the first layers of paint (Plate 29c). The subsequent layer of paint fo llows
the line denoted by this "correction" layer. Optical microscopy showed the
pigment here is charcoal (13). Two panels, The Miracle if the Purse and The
Metzger and Berne^129