I made a big mistake the other night. I had 3 rolls of film to develop, which I had to do in two batches since my Patterson tank only holds 2 (glad it doesn't hold 4 or would have been worse).
I developed the first batch - no problem.
Time for the second batch. I remembered an old roll of film I found cleaning a drawer and decided to make it the second roll of the batch. I had no idea what was on it - really didn't care, since if I hadn't developed it - it must not have been that important. It was a different kind of film but my time for it is only about 30 sec. different using straight development and I've been using semi-stand so I figured what the heck the time would be that off.
I processed and when I got done the old roll was a mess. It looked like something had leaked into the roll and dried. Not sure why I didn't notice anything while loading the reel. I looked at the other roll and it was cehmical stains from the other roll all over it. Totally useless and it was a trip to a ghost town in Montana. Luckily I have my 4x5 shots and I'll be back in the area next month.
So if you have that roll of film that you don't know much about - process it by itself!!!