The section is placed on a glass microscope slide and covered with a thin
cover glass; enough water is added with an eyedropper to surround the
tissue section without excessively flooding the area under the cover glass.
When placed on the stage of a standard compound light microscope, the
translucent section is illuminated with transmitted light, and the cellular
detail can be examined at magnifications up to 500 3 (Fig. 3).
Slicing of the section is most critical to success. Initial surfacing
cuts might be made with a sharp knife, a replaceable scalpel blade, or an
industrial-type razor blade, but sectioning of tissue is best done with a
double-edged or equivalent-quality razor blade, although these blades may
be too fragile for higher-density woods, especially on transverse surfaces.
It helps to moisten surfaces with water prior to sectioning. For small
pieces removed from the panel, sectioning will be much easier if the
sample is boiled or soaked in hot water for a few minutes. Sections should
be removed with a smooth, sliding, slicing action, rather than by pushing
or forcing the cutting edge directly forward.
Sections should be sliced as thinly as possible, ideally not more
than one or two cell diameters thick. Skimming offseveral tiny, thin bits
(1–2 mm across) will usually yield better results than attempting to take a
larger single section, which will be mostly too thick to show detail. With
hand sectioning, the sections will not be uniformly thin, but if they are
well cut, they will have appropriately thin areas near their edges where
detail will be visible.Table 1 lists woods common to painting panels. This selection will proba-
bly account for the species found in well over 95% of painting panels.
Species within most genera cannot be separated on the basis ofwood tis-
sue alone. Nevertheless, in cases in which different species are found in dis-
tinctly different geographic localities, the known origin of a painting may
suggest a probable identification. This section presents key diagnostic fea-
tures ofthe woods listed in Table 1 and provides the reader with a founda-
tion for identifying them in painting panels. It is highly recommended,
however, that the reader examine known samples of woods and consultSurvey of Panel Woods
I W P P 25Figure 3
The small specimen ofwood near the razor
blade is sufficient for identification. A clean
cut ofa transverse surface reveals the orienta-
tion of the rays and growth rings, enabling
accurate radial and tangential surfaces to be
prepared. From any of the three principal
surfaces, a tiny, thin section can be removed
with a razor blade and mounted on a slide
with a drop of water for microscopic exami-
nation, as shown.