I once had a pro photographer come to our mastering studio. He needed photo's recovered. It seems he'd been in South America on assignment. He burned his pictures to CD-R's, as a back-up, during the trip. But, he wrote notes on the surface of the discs, cataloging what was on each disc. The sad thing, he used a ball point pen, which literally scribed the notes into the surface of the discs. He ruined all the the discs with the hand writing scratches. Nothing would read, on Mac or PC, trying multiple drives and recovery software.