The attached scans show a pair of symmetrical artifacts I found on a recent negative. There are two blurred dark lines perpendicular to the long edges towards the right hand end of the scan. Presumably if they were light leaks then they would be bright not dark, so I assume that they must be something else. The film was in a standard Toyo 5x4 film holder. Other shots with different holders on the same day didn't have this so I presume the problem lies with the holder not the camera. I haven't used this holder since, although I plan to run some tests when I get the chance. However I have done a physical check and can't see an obvious cause. Has anyone seen anything like this before, or can you suggest what I should investigate? The only thing I can think of is that I may have bent the film as I slid it in or out of the holder. Could this be it?