Bromide free Ferricyanide bleach?

[Marco B]

Here is the example, the pull is worth around 14 stops, the exposure was only +10 stops though.

That surely must be one of the most extreme examples of Zone System usage ever! I guess you did this in an attempt to equalize out the difference in light and dark values between the foreground and sky? (although isn't 14 stops way over the top for that).

 

[Athiril]

Zone system? I dont use that

This was when I was using Rodinal as a first developer, seeing as 1+50 took 2 hour 20 min on C41 film @ near 40c to make a good reversal, I was wondering about a colder shorter process.

So I was like "hmmm, I'll just add 10 stops and develop it for this long at ambient and see what happens!" underexposed for the dev time still, but not too bad


Edit: Im guessing as far as the bleach goes.. fogging/exposing and developing a film to the whole thing is at maximum density then using a regular/bromide bleach with a little chloride mixed in to partly rehalogenise the emulsion to less sensitive would not work in the way I am thinking - highlight retention with heavily increased exposure?

 

[clayne]

By the way, reading that document, Wilco refers to the possibility to have a bleach without a halogenide in it, so just ferricyanide, as in that case all of the silver is converted to a silverferri/ferrocyanide complex, which is a very yellow light to almost colorless complex. With bromide in it, a big part of the silver complexes to AgBr too.

I am not sure how well or at all it will redevelop though, and if it has any bleaching speed. However, it is interesting that the formation of silverferri/ferrocyanide complex during bleaching is often ignored in discussions here on APUG and the net.

I just did this last night actually. I had some left-over straight pot-ferri bleach from bleaching other prints and decided to fully bleach-back a previous unrelated 5x7 print. However, I had forgotten I Se toned it so of course only the high-mids and highlights lightened and went to ferri yellow. I then rinsed it and placed it in a tray of Rodinal 1+50 which easily redeveloped back all the bleached silver in around 2 minutes or so.

I did not add bromide when mixing the initial bleach bath.