I ordered some sodium thiosulfate. It took a while to come. Until the hypo came I only had two images left, the first two I made. All others faded away or turned black.
I have given up on the long duration sensitization. It had it’s charms, but there seems to be something unstable about a sensitization layer created over such a long time. All of those images vanished in the fixer. By reducing the distance between the plate and the pool of tincture of iodine to just a few millimeters, sensitization times are reduced to the range of five to eight minutes. All of these turned black over time.
I created a couple of tests today and fixed them with the hypo I just received. So far they seem stable. I appear to be back in business.
I have thought about using silvered glass. I was going to use a common technique for silvering homemade telescope mirrors. This technique uses Tollens’ Reagent. I have not gotten around to it yet.
I considered saturated sodium chloride solution. But from what I understand it has to be heated. The silver leaf is currently held on my plates with paraffin. This limits the temperature range of any solutions I use.
I will report back after some more experiments. Thanks for your help!