Series editors' preface - Wood Tools

various materials that make up the object
rather than specifically identifying each component.
Characterization seeks to determine,
for example, the appearance, condition, layer
structure, solubility and fluorescence characteristics
of a coating to help uncover the history
of the piece and to determine treatment needs
and options. It is somewhat distinct from the
process of analysis that is used to confirm the
specific identities of particular materials.
9.3.2 What to look for
In general terms there are two kinds of evidence:
evidence from the object itself and
related evidence which comes from the previous
environment, from documentation, from
other members of sets or from related objects.
Evidence from the object itself includes the
materials, construction and condition of the
object and the overall quality and variations in
quality of these things. An essential aspect of
knowing what to look for is to know the kinds
of materials and structures that were used in
furniture at different times and places. It is also
essential to become familiar with the properties
and characteristics of materials and their modes
of deterioration and failure. The more complete
one’s knowledge of the macroscopic and
microscopic features of materials and of their
physical, chemical, optical and other properties
the better one is able to lead an examination
and the better one is able to attach significance
to what is observed. The fact that a certain pattern
of cracks may be observed in a surface
coating may not mean anything by itself. It is
essential that the observer has the knowledge
to interpret the observation.
The most obvious question about furniture
during examination is: what wood is it made
of? However, attention should also be paid to
any metal fixtures, fittings or fastenings, ceramics,
upholstery materials, adhesives, coatings
and other materials that may be present, either
as part of the original structure or as repair
materials. The use of certain materials and certain
processes was developed at certain times
in the past and this may provide a guide to age
and authenticity (Bowman, 1990; Kaye, 1991).
Whether the materials and techniques of construction
(both original construction and signs
of alteration) are consistent with what would
be expected for a piece of the supposed age,
Conservation preliminaries 381
origin or maker are frequently asked questions.
Usually, if a material or technique turns up in
an object at a date earlier than expected it will
throw suspicion on the piece. However, where
supporting evidence for the age of the piece is
irrefutable it may point towards the need for
revision of the chronology for that material or
technique.
The overall shape of the piece, its structure
and evidence of methods of construction may
help to support the authenticity of the object,
add to our knowledge of the type and contribute
to our understanding of how the piece
should be treated in the context of present
condition and desired end use. Hidden elements
of construction may, under appropriate
lighting conditions, be read in the surface
where they ‘telegraph’ their way through to the
surface as undulations revealed in the pattern
of light reflected at the surface. This is particularly
useful for elucidating the structure of
objects which have been veneered or in which
the method of construction is otherwise hidden
by paint or gilding. These patterns may be
revealed even through very slight differences
in thickness that arise through moisture
induced-dimensional change of components
with differing grain orientations.
Various properties of different materials that
vary in some predictable way with time or
which have changed radically at a particular
point in time have been used to determine the
age of materials. The techniques of radio carbon
dating and dendrochronology that can
sometimes be used with wood may be helpful
in resolving its age and are further discussed
below. It should be remembered, however,
with all such techniques that what is being
measured is the age of the material or component.
This does not necessarily confirm the age
for the entire structure. An object made from a
tree that was felled in 1920 cannot have been
made in the seventeenth century but wood
from a tree that was felled in 1620 could have
been used at any subsequent date. Similarly
old screws could have been used in new locations
or those in an old structure replaced with
new ones, although some clues to what has
actually happened usually remain.
The presence of various kinds of marks,
inscriptions and labels can also provide valuable
information about provenance and methods
of construction. Occasionally stamped