I have been working for a while with Leonardo3, with the collaboration of Hasselblad and Manfrotto, on high resolution reproductions of Leonardo da Vinci's drawings, Atlantic Code, The flight of Birds, and drawings from the Royal Library of Turin, one of which is the very famous "Self-portrait". A very complex, delicate but exhilarating work.
This is an extraordinary story. The story of a lazy assistant who misplaces a box with a lot of transparencies, outside, exposed to the weather, to the heat, to bugs. The negatives stick together, they transform, dirt, insect parts and other unknown particles become part of the gelatins.
Last September I had a great opportunity  to take photos of the splendid National Gallery Collection of Cosenza, in the southern italian region of Calabria. It was a very demanding task and  many of the works showed deeply toned areas , apparently showing no detail. Effectively, they were full of different shades and detail was quite amazing..