Until 2012, digitized scans of old photographic negatives, acquired
by Alfons Dierick [12] and kept in the archives of Ghent University,
were the only available high-resolution data set of The Ghent
Altarpiece. The development process of these negatives was
mainly undocumented, which resulted in a data set where the
images vary strongly in quality. Earlier reported results of digital
image processing on The Ghent Altarpiece, such as crack detection,
virtual crack inpainting [7], [24], and pearl analysis [23],
were all based on images from that old data set.