>>2706964Before spending money on film, check that the bellows (the collapsing concertina part) is actually light tight. It is quite likely that tiny pinprick holes will have formed on the corners, or cracks along the folds.
Take the camera into a dark room/cupboard, open the back & shine a bright light (torch on your phone, maybe) down into the bellows. From the front look for any light escaping through the bellows, paying particular attention to the corners & folds.
If there are any holes, you can temporarily patch them with opaque tape (might prevent it from collapsing properly) or permanently patch them with Plasti Dip.
Picrelated, I had to patch it up but it was easy enough & works fine years later.
