An x-ray image revealing the extent of wood worm damage to a flintlock gun stock


Most people are familiar with the use of X-radiography in hospitals. The same principles apply to the use of X-rays in a museum, though we may use longer exposures to penetrate metals and other dense materials.

X-ray is a useful tool for the conservator as it can help us discover ‘hidden’ constructions and mechanisms, which we otherwise couldn’t see. It can be used to consider the extent of deterioration of an object or to check whether a firearm is loaded. A major advantage of this technique is that it is entirely non-destructive.

X-rays form part of the same electromagnetic spectrum as radio waves, ultraviolet and visible light. However, their greater energy compared to visible light allows them to pass through much denser materials. Light can be stopped by a couple of pieces of paper, whereas X-rays, if their energy is sufficiently high, may penetrate several centimetres of steel.

The X-ray beam, however, will be partially absorbed by the object and the intensity of x-rays is reduced when passing through denser parts of an object.

Photographic film is sensitive to X-rays and a sheet of this is placed below the object being examined. After developing the film, the less exposed areas beneath the denser parts will appear lighter. The completed X-rays are scanned to produce digital images for use in reports and presentations.

The gun shown in the header image has suffered from insect damage, and the weakened wood of the stock has been filled with an adhesive to strengthen it. The adhesive has a higher density than the wood and so the extent of the woodworm damage is visible on the x-ray.

Uses of X-Radiography

Did you know?

American gifts re-open Japan in 1853

15 rifles, 3 muskets, 12 cavalry swords, 20 army pistols, 2 carbines, 2 telegraph instruments, a model steam locomotive and tender, 4 volumes of John James Audubon’s ‘Birds of America’, and 1 barrel of whiskey for the Emperor and much more!