Posted 04 July 2016 - 03:07 AM
If the double image jumps around and you can see the frame lines, then it's probably a registration issue. If it's only the highlights that are moving and the rest of the image is solid, then it's probably a shutter timing issue.
A simple test for shutter timing is to take a dummy load and draw a squiggly line on the emulsion side with a sharpie. A few feet should be more than enough. Load that up in the mag and use the inching knob to move it through the gate. Remove the PL port cap and look at the emulsion thru the gate as you inch the movement. If you can see the squiggly line moving at all, then that means the film is being pulled down before the shutter completely covers the aperture - you have a mis-timed shutter.