Plate 20. Cross section oj Sample 3, taken
Jrom the olive-green background near the leg
oj Nicodemus in the Deposition on the
east wall. The charcoal black inclusions
within the plaster substrate are clearly vis
ible; over this, a layer oj natural ultrama
rine is present. The present green appear
ance is due to the layer oj vivianite on the
suiface oj the sample. Originally a blue col
or, some oj the particles have altered to a
yellow color, and in the center oj some oj
the yellow particles, the original blue color
is just discernible. Photograph courtesy oj
the Conservation oj Wall Painting De
partment, Courtauld Institute oj Art, Lon
don.
Plate 21. Photomicrograph oj sample from
central porch tympanum, Salisbury. Cross
section shows complex structure, represent
ing several repaintings and including ver
milion, red and white lead, iron-oxide red
and yellow, black, blue, and possibly gold.Plate 22. Photomicrograph oj sample Jrom
Exeter west Jront. Cross section shows pink
primer, white lead, and verdigris top layer.