RE: GENTLE BLEACH

Yes, develop, water bath (not acid stop), sepia toner followed by
halogenising bleach and fix will give you a negative, but the resulting
enlarged neg was almost completely opaque to UV, even in the shadows, the
one time I tried this. Maybe the problem was a high fog level that could
possibly be cured with longer first development &/or exposure (i.e.
producing a denser silver image), but too long ago for me to remember
exactly what the result looked like. The technique can be effective for
paper prints in brown negative, but you'll have to experiment.

For reversal, you need a non-halogenising bleach that dissolves metallic
silver WITHOUT altering silver halide, and I'm not aware of many suitable
bleaches. Mike Ware suggested a bleach based on cerium nitrate, but I found
it extrememly slow. It's also a great deal more expensive than permanganate
and dichromate.

Liam

-----Original Message-----
From: Ryuji Suzuki [mailto:rs@silvergrain.org]
Sent: 02 June 2005 23:01
To: alt-photo-process-l@sask.usask.ca
Subject: Re: GENTLE BLEACH

From: roy beecher <vintage.florals@operamail.com>
Subject: Re: GENTLE BLEACH
Date: Thu, 02 Jun 2005 22:44:47 +0100

> I was wondering if this formula would be suitable for bleaching back
  inter-positives as part of the process of turning them into
  negatives for contact printing. On another forum a member reports
  having successfully used Kodak Liquid Developer System Cleaner
  obtained on an auction site and diluted, for this purpose.

Interpositive? Umm... I don't think bleaching is generally involved in
that process.

Do you mean reversal processing? If so, that wouldn't work. You'd
need dichromate, permanganate or similar bleach for that. Someone here
(maybe Liam?) suggested sodium sulfide redevelopment followed by
ferricyanide and fix as a way to avoid environmentally harmful bleaches
though the image may not be neutral black.

--
Ryuji Suzuki
"Well, believing is all right, just don't let the wrong people know
what it's all about." (Bob Dylan, Need a Woman, 1982)