[pure-silver] Re: Chromogenic toning?
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 21 Jan 2005 18:03:48 -0800
----- Original Message -----
From: "Nick Zentena" <zentena@xxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, January 21, 2005 5:35 PM
Subject: [pure-silver] Re: Chromogenic toning?
> On January 21, 2005 05:49 pm, Richard Knoppow wrote:
>
>>
>> I wonder what, if any, advantage chromogenic toning
>> has
>> over simple dye toning of prints. Dye toning is an old
>> process where the image is bleached using a bleach that
>> acts
>> as a mordant for the dye. The only special chemicals
>> needed
>> are the dyes. Kodak has published at least two bleach
>> formulas over the years. Perhaps there is a more modern
>> bleach available.
>
>
> I haven't done either so can only quote Rudman's toning
> book
>
> "In chromogenic dye images, therefore, the whites remain
> white and the greys
> and blacks change colour. In gelatine-dyed images the
> whites change colour
> and the greys and blacks remain the same"
>
> So it sounds like the final result would be different. A
> winter scene with a
> tree surrounded with snow would in one case have white
> snow in the other
> coloured snow.
>
> The formula posted by Gerald only requires the colour
> couplers. The rest of
> the chemicals are common enough. I did a google search
> today and found a
> bunch of MSDS for the couplers so somebody must be selling
> them.
>
> Nick
>
I have a _very_ high regard for Tim Rudman but he is
wrong about this. I think he is confusing _tinting_ with
toning. Tinting if done by staining either the gelatin or
the support and is as described. Dye _toning_ is done by
converting the silver to a substance which acts as a mordant
for the dye. It is then removed by fixing leaving the dye
image in the gelatin. If done right neither the gelatin
itself or the support is dyed. The whole idea of a mordant
is that the dye sticks to it in preference to the genatin in
which it is embedded.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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