I've had a close call with the bitter taste of failure this past week. As you may know I pre-mix the soda, vitamin-C and coffee solutions beforehand and mix them together from stand bottles as and when I develop. Also have in mind I'm not yet very experienced in such things, yet.
I thought I'd mixed my latest batch all wrong. Well, that was until I remembered I had developed several films from the same batch already, with success. But once you experience not one, not two, but three films in succession going down the drain, the brain tends to go into panic mode, and reason out the window. I'd started using Acros100, with no prior experience in other developers. Since I use the CC-H/M recipies from Caffenol.blogspot.com as a starting point for all my Caffenol endeavours, I browsed the blog for information on Acros. I found that with an EI of 200 CC-M at between 12 and 15 minutes would be a good starting point. So I went about my first film 15min @20C. Two useable negatives, even those very dense. The other ten, grossly overexposed or developed and virtually opaque. Without a light table I could not really tell which. Had my brain been in gear I'd have seen that the border tags were just a tad overdeveloped, but not much. But alas, brain not engaged as yet. Overdeveloped I thought, so next film, same exposure regime, but 12 minutes @20C. Same result more or less. Maybe a couple of negatives could be salvaged. A third film 11min @20C EI400 and still no luck. Finally brain engaged, this can't be down to development only. I went about checking the light meter (a recent purchase), exposed and developed a roll of TMX previously loaded into another camera, and all was normal. Oh, sh-one-T, its the shutter, it has to be the shutter. Its been recently serviced, it can't be, surely? Yet it did turn out to be the culprit. I tested the leaf shuttered lens off camera, and it sticks. Its a wonder anything resembling a negative came out at all.
I was worried for a moment there, I would not liked to have found out I'd all of a sudden lost my grip, its better to know that a mechanical malfunction is to blame, rather than any inadequacy on my own part.
Good part is that you now have your batch mixing, light meter and Acros dev times thoroughly tested!
you should try to contact print your over developed negatives with a strong light.
you may be surprised at the quality of your images.
mortenson did this often.