Some devices that gave excellent results for matte colour charts proved to have poor performance for this demanding test object. Specular reflection also degraded the accuracy of the reconstructed reflectance spectrum in some places, indicating the importance of control over the illumination geometry. There was a surprisingly wide variation in the quality of imagery, caused by unwanted reflections from both glossy painted and metallic gold areas of the icon's surface. The differing spatial resolutions of the systems affected their ability to resolve fine details in the printed pattern. The image quality was assessed by observers, and the reflectance spectra at selected points were reconstructed to characterise the icon's colourants and to obtain a quantitative estimate of accuracy. A Russian icon, mass-produced in Moscow in 1899, was digitised by ten institutions around Europe. In a study of multispectral and hyperspectral reflectance imaging, a Round Robin Test assessed the performance of different systems for the spectral digitisation of artworks.
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