I am getting horizontal lines on all frames. On BW film, it's a black line. On color film, it's a green line. Is this a light issue with my curtains or maybe something scraping the negative as I advance. I use an OM-1 with different lenses and same results. I develop my own BW but have a local lab develop my color. All come back with small lines. 90% of them are 1/3 down from top but some are 1/3 from bottom. The lines are approximately 1/8 inch thick on BW and 1/4 inch on color. Any help in identifying the issue is greatful.