From: Judy Seigel (jseigel@panix.com)
Date: 09/23/02-12:56:00 PM Z
Bernhard,
I've never used the brown scales, but the old magazines about the
time the switch kicked in did explain that the green was faster (therefore
better!). I don't recall if they gave an amount. But just for the heck of
it, I'd guess (a feeling in the air !) about half.
Judy
On Mon, 23 Sep 2002, Bernhard Wittek wrote:
> 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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