From: Ed Buffaloe (EdBuffaloe@UnblinkingEye.Com)
Date: 09/23/02-02:35:34 PM Z
I've always used the green form of ferric ammonium citrate, and my exposure
times by UV rarely exceed 30 minutes and are sometimes as low as 5 minutes.
----- Original Message -----
From: "Bernhard Wittek" <bw@infosolutions.de>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Monday, September 23, 2002 7:59 AM
Subject: speed of van Dyke Brown process, green salt - brown salt
> Hi list,
>
> beside gum printing, cyanotype and carbon I am doing some experiments with
VDB since a few weeks. Works fine, but unfortunately my exposure times are
up to two hours with my regular UV light source (time for carbon printing
for instance is around 10 minutes using the same light source!) I found
several notes in the literature concerning the use of the right modification
of ammonia ferric citrate, which should be of the green form. On the face of
it I' ve got the brown form ;-) which is assumed to print much much slower
than the green salt. Does anybody have experience if speed might be improved
using the green salt? And if so, how much faster could it be?
>
> thank you,
> Bernhard
>
>
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