Here is a technique that solved a lot of problems loading SS 35mm reels for me. First, when rewinding the film, leave the leader out of the cartridge. If the leader is already in, try to retrive it.(If you use reloadable cartridges, you can open them, retrive the leader, and then close it back up). Be sure to crip the leader so you know it is exposed!(posted 9153 days ago)In room light, cut the tongue of the film off and then cut about a 1/4" off each corner of the film at a 45 degree angle. Now place the cut end into the spring catch and start the film on the reel. Since you are working in the light, it is easy to get the film started correctly. Once you have the film started, turn off the lights and proceed to load the rest of the reel. Cut the film at the end and place it in the tank. Turn on the lights and repeat for as many reels as you want.
Getting the flim started right is the answer to 95%+ of loading problems. Sorry, It won't work for 120!