RE: GENTLE BLEACH

From: Liam Lawless ^lt;[email protected]>
Date: 06/04/05-09:50:10 PM Z
Message-id: <NAEMIKEPOCCEOGOHBLBGIENHCEAA.liam.lawless@blueyonder.co.uk>

Martin,

Thanks for that suggestion. I'll give it a try if I have the necessary
ingredients, which I think I probably do.

Liam

-----Original Message-----
From: MARTINM [mailto:martinm@SoftHome.net]
Sent: 04 June 2005 05:43
To: alt-photo-process-l@sask.usask.ca
Subject: Re: GENTLE BLEACH

----- Original Message -----
From: "Liam Lawless" <liam.lawless@blueyonder.co.uk>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Friday, June 03, 2005 1:15 AM
Subject: RE: GENTLE BLEACH

> 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

It might be possible to form a reversal bleach based on ferric nitrate (or
ferric sulfate) + potassium persulfate. At least for ultra-fine silver
grains it works nicely:

Ferric nitrate (or ferric sulfate).....100g
potassium persulfate.....................20g
water.............................................1L

Martin
Received on Sat Jun 4 21:50:12 2005

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