Yes, thanks Niranjan, I saved too, and intend to explore this process more.
I've added a small amount of AFO to Sepia/VDB-like prints a couple times, but always keeping it below the level where the precipitate forms ( so still mostly AFC ). I haven't done it enough to have much to say, the only things I noticed were slightly faster printing and slightly colder tones... but there are a lot of variables, and both of those things could depend on paper/acid type/etc. I'm particularly interested if it might change the characteristics for platinum toning ( before or after fixing ). I've been making a lot of these kinds of prints the past couple weeks, so I'll add this to the list of various things I'm trying. At the moment I'm still working out some things about exposure, and am not at the stage yet where I'm toning, but when I get to there I will change up the AFO/AFC ratios and see what happens. ( Naranjan: I've been meaning to PM you about some things I'm trying related to UV-blocking in the negative, it might be relevant to your POP printing, but am waiting until I have more results! )
About 6 or 8 months ago, I spent a good amount of time working with AFO/AFC in gelatin. I've got a pile of about a hundred test strips! No silver nitrate, I wanted to see if it could be used in Winther's process and was hoping that using AFO would speed things up enough to make in-camera use feasible. In this case, "feasible" means anything less than 6 or 7 hours in full sun. I didn't get there. I have suspicions about air re-oxidizing the ferrous back to ferric and making longer in-camera exposures an exercise in diminishing returns... and I have some ideas about things that might help ( mount the paper between sheets of glass and use a plate holder, or coat it in agar or something else to exclude the air ) but it gets fussy not as fun and not quick like making the paper and sticking it out on the back porch in the sun to see what happens!
Edit: Recently I did notice something odd about AFO in those tests. In this process, after washing and clearing the gelatin relief, you let the gelatin dry, paint it with potassium chloride, let it dry again, paint it with silver nitrate, dry, then expose to the sun until you see the positive image you want ( then fix and wash like a salt print ). Looking at the test strips months later, I noticed that the ones made with more AFO had silvered out more... some of them have extensive bright silver. Weird, because this must be something different the AFO does to the gelatin... the iron salts are completely washed out earlier in the process.
