In the spirit of scratches, it was only at a recent 70mm film screening that I spotted the rig used for the floating pen scene as Floyd falls asleep in the shuttle.
As the weightlessness begins, his pen floats away - if you look really really carefully you can spot that it’s actually embedded in a thin plastic film which is rotating about an axis, given away by minute scratches on its surface.
They literally taped the pen to a sheet of glass, which they rotated around. As low-tech as it gets but it looks wonderful, except I guess for the scratches you spotted.
As the weightlessness begins, his pen floats away - if you look really really carefully you can spot that it’s actually embedded in a thin plastic film which is rotating about an axis, given away by minute scratches on its surface.