This is what can go wrong with slide copying. I was experimenting using bellows, a reversed 50mm lens and a light box to illuminate a slide of Cygnus and the North American Nebula. This was illuminated with a flashgun and a homemade diffuser. The diffuser was too close to the slide. This has given uneven illumination and a mottled effect from the diffuser surface. The resulting image does give a good impression of a star cluster or small galaxy.