Quote Originally Posted by nwilkins View Post
no that is inverted to a positive. so in reality the line is clear on the negative. basically looks like a line where there is either no emulsion (a scratch?), or where the emulsion was not exposed to light (which seems unlikely, no?)
Sounds like something is intruding into the edge of the film gate, and therefore blocking the light.

Is there a problem with the film gate, such as a loose piece of film from the dark slide channel?

Is the back not mounting correctly to the rotating adapter?