“Volumetric X-ray Imaging of Art and Artifact”

Use of X-ray imaging permeates the process of art and artifact care and conservation. Possession of 2- and 3-dimensional knowledge of the condition and construction of an object can provide the conservator with interesting and even essential information. A newly available volumetric X-ray imaging technology will be described in this presentation. The Digitome® technology uses a series of 2D digital radiographs taken from different perspectives exploiting two degrees of angular freedom. Each radiograph contains the entire volume to be examined so no interpolation between slices is necessary. Radiographs are taken in transmission and gathered with digital radiography (DR) or computed radiography (CR) image plates.

We have applied this fully portable technology at a number of museums in examining paintings, art objects and cultural artifacts. A silver coin, imbedded in a 300-year old saltwater concretion, was initially identified by separately imaging the two faces of the coin. All of the silver had converted to silver oxide, Ag2O, but diffusion was limited by the surrounding concretion. Paintings on wood or canvas have been imaged while suppressing contributions to the view caused by supporting understructures in the form of wood grain, cribbing or stretcher bars.  Conservators and art historians can then focus on the regions painted with metallic pigments. Using relatively low energy x-rays, objects with low absorption can be imaged such as paper items with watermarks and with double-sided print. Text can be read and paper thickness measured even when the paper is placed within a sealed envelope.