From: Christina Z. Anderson (zphoto@montana.net)
Date: 06/22/02-01:46:07 PM Z
Hi Sam!
Ferricyanide is a reversible bleach. I mix 100g of pot ferri with 100 g
of pot bromide to 1 liter water, and use that 1:9 for my bleach. Negs will
redevelop in anything after this bleach--a little contrastier tho. Which is
what I think you want. The grain will also increase a bit. If you bleach
and then get the neg to where you want it to be, and then fix, it'll be
permanent. If you bleach and redevelop to completion it'll not need
refixing. If you do not develop to completion you need to refix. Watch,
tho, that you don't overbleach because it will lighten more when you put it
into the fix. I rinse really well after the bleach so all pot ferri and pot
bromide is gone and then fix.
I have not used the dichromates so am not experientially knowledgeable
on this.
Chris
----- Original Message -----
From: "S Wang" <stwang@direcTVinternet.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Saturday, June 22, 2002 12:31 PM
Subject: photographic bleach
> I have a question about the various types of photographic bleach. In
> general terms, are the dichromate bleaches reversible while
> ferricyanide ones not, that is, the dichromate changes the state of
> the silver, whereas ferricyanide removes it?
>
> The reason for asking is that I am looking for a way to bleach and
> redevelop some over-developed (in pyro) negatives. My tentative
> trials of using the bleach from Kodak Sepia Toner seem to be
> promising without using anything else, that is, without clearing,
> redevelopment, or toning. I suspect the image not to be very stable,
> but would like to hear a knowledgeable opinion. What bleach do you
> use for bleach-and-redevelop? It appears that the chromium
> intensifier formula posted by Judy may be a good one to try. I assume
> that you can control and hold back redevelopment, so as to make it a
> reductive instead of an intensifying process.
>
> Anyone with chemistry background still around this time of year?
> Thanks in advance.
>
> Sam Wang
This archive was generated by hypermail 2b30 : 07/02/02-10:33:22 AM Z CST