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Wood is an ideal material for studying with a CT scanner, firstly because it is an organic material that is partly dehydrated and therefore of low density, and secondly because it has growth rings of varying density, arranged in a regular pattern which is disturbed by the least tampering.
A CT scan study of growth rings in a wooden sculpture can be a valuable aid for detecting the assembly of different pieces of wood, whether they are of the same or different species, as well as
any gluing or breaks; it can even be used to identify the species. It can be still done if the sculpture has been covered with opaque varnish, or a thick layer of patina or paint, even if the
latter contains metallic pigments such as white lead. This is often the case for polychrome wood sculptures, on which paint and patina may be used to hide defects.
For wooden sculptures, CT scanning has the added advantage of showing the extent of damage caused by borer or termites and even detecting the eggs or larvae of living wood-boring insects. Such a diagnosis is valuable in recommending a conservation treatment such as anoxia in a nitrogen environment.
In the tribal art field, ritual stigmata, fetishes or magic charges are sometimes concealed inside the sculpture or under a layer of condensed organic matter, and non-invasive investigation may shed light on their nature and original function.