Lux in Tenebris: a workflow for digitizing and visualizing pictorial artworks in complex museum contexts

In museum contexts, it is common to meet logistical limitations that make it difficult to document artworks. The pictorial heritage introduces further challenges due to the non-modifiability of the lighting setup, which is based on preservation and communication criteria that emphasize the material and execution characteristics of the artwork. This can result in situations that are unsuitable for conducting surveys based on photographic images, which are already complicated by the optical properties of areas covered in gold leaf. The data processing technique described here was developed for the documentation of the Annunciation (1430-32) by Fra Giovanni Angelico (Museo Basilica S. Maria delle Grazie, San Giovanni Valdarno, Arezzo) and it offers the elimination and mitigation of undesirable phenomena due to the specific conditions of the museum context. A strategy capable of removing shadows and chiaroscuro effect from the textures associated with the digital model of the painting and its frame is presented, ensuring its visual reliability.