Shutter Curtain Problems in the Screw-Mount Cameras
First photo shows results from pin-hole light leaks in curtain(s) due to dried out rubberized side of curtain. Shutter curtain(s) needs replacing. Completely different problem- 2nd photo shows dark streaks throughout image due to the rubber from the curtain squeezing through the threads of the cloth curtain material. Following photos magnify the curtain. This only shows up on photos shot at high speeds since the opening slit between both curtains is so thin that even the slightly protruding rubber "bumps" will cause dark lines to appear in photo. Sometimes scraping off the rubber bumps is not good enough. Replacing the curtain or curtains is best.