Use of GIMP Retinex filter to enhance the visibility of craquelure

This is the fifth work of a series which is showing applications of Retinex filters. In the first paper, we considered the images from microscopes. In the second, we discussed how a Retinex filtering can help us in the investigation of motion of sand dunes. In the third and fourth, underwater and night images have been considered. Here we give examples concerning an application to artworks. We show how the visibility of craquelure can be strongly enhanced by means of Retinex filtering. Used filter is GIMP Retinex, based on the original Retinex method developed by Fabien Pelisson.