As I fully understand why it happens, I normally process disks through desiccant to remove moisture.. even after low temperature 'baking' a disk needs to be moved to fresh media and archived in other forms, be it hard drive or solid state media. Magnetic media can naturally lose it's patterns over time (some call it bit rot), and of course disks improperly stored or defect of manufacture does not help.
Some disks look fresh as the day they were born and the pattern is degraded less than a few percent, other disks have that tell tale haze about them, or that rusty dusty look... or in the case of the above disk... what appears to be material literally falling off the disk.
Very pleased at the resulting image. I am moving on to the next disk. It is imperative that the community and collectors alike image their disks. I am pretty sure we have discussed why and how at some length, it's on an Atari Age thread somewhere It also helps to have brand new sealed floppies of decent manufacture to write images to. Of which being blessed to have a few is nice.
Edited by _The Doctor__, Wed Apr 19, 2017 4:24 PM.