> No, they’re just from using the Q-View magnetic developer & iron nanoparticles, which I don’t think give fine grained enough detail for floppy disks unfortunately and then just imaged with a cheap usb microscope.

I wonder if this could be improved with, say, a Canon 6D and macro lens with a lossless image format. Better resolution, fewer artifacts.

Yeah that's a good point. I've got an Olympus BHM metallurgical microscope now along with the camera attachment for an SLR which I should try out for this.

Definitely give it a shot and let us know! I'm really curious about this and it really should be possible as long as you can visualize the magnetic field.

For comparison's sake (several orders of magnitude physically larger), apparently it's entirely possible to visually "read" vinyl records: https://www.wired.com/2003/02/press-scan-to-play-old-albums/