Towards a combined use of IR, UV and 3D-Imaging for the study of small inscribed and illuminated artefacts

When heritage objects are being transformed into digital representations, the loss of information is inevitable. The challenge lies in developing integrated systems able to minimize this loss and bring together as many different kinds of recordable characteristics as possible of one and the same object. This contribution presents an approach that combines the detection of colour, surface shape and the reflective characteristics of surfaces by using a selection of IR, Red, Green, Blue and UV light spectra and applying them on 3D models. A multispectral, multi-directional, portable and dome-shaped recording tool has been developed to this end. With the associated software, virtual relighting and enhancements can be applied in an interactive manner based on the principles of photometric stereo: this allows alternating in real time between computations with IR, R, G, B and UV light spectra. Throughout the testing phases, this non-invasive registration and documentation technique has been applied to monitor and study a vast number of heritage objects, varying from 19 c. BCE Egyptian inscribed clay figurines to medieval illuminations.

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