Re: dichromate stain

From: Clay ^lt;>
Date: 06/16/04-09:01:55 AM Z
Message-id: <04af01c453b2$ef91f260$0ec809c0@peewee>

Just to throw some more information on the table here, I have discovered in
conversations with Kerik Kouklis that while we both use virtually identical
techniques in terms of paper (Fabriano EW), type of gum (B&S) and amount of
dichromate(saturated Am-Di), sizing (3-4% B&S gelatin) and coating technique
(rollers), I get dichromate staining and he gets none. Which leads me to
think that the only real difference has to be the water we use for

I know that my water supply here in Houston has quite a bit of iron in it.
If you allow the tap water to evaporate from a container, a fine film of
hematite (iron oxide) is left behind. I don't know what is in his water, but
I am betting it is different than mine. Maybe the chemists in the crowd can
put forward a hypothesis as to why iron rich water would be more likely to
induce dichromate stain.

The whole subject is only a minor issue to me because I have to be careful
in evaluating the color of my highlight areas since it picks up a greenish
tinge from the staining that will disappear when I clear the stain with
potassium bisulfite.

my 2 cents

----- Original Message -----
From: "Katharine Thayer" <>
To: <>
Sent: Wednesday, June 16, 2004 2:38 AM
Subject: Re: dichromate stain

> Keith Gerling wrote:
> >
> > I've been too busy printing gum to read about printing gum,
> As one who spent most of the day yesterday trying unsuccessfully to
> produce dichromate stain, I say you really know how to hurt a gal, don't
> you! Finally at the end of the day I remembered about that
> Photographer's Formulary gum that stained with some pigments, and I
> found one of those mixes and printed it and did get some dichromate
> stain. But there's no doubt it was one of the stupider ways I've spent
> a day in my life.
> but for the
> > record:
> >
> >
> > 1) Using halogen, fluorescent UV tubes, and a Violux plate burner, I've
> > never had dichromate stain. I've never seen it. In fact, I'm not sure
> > know what it looks like. (so maybe I do have it... nah - I've used
> > Bisulphate on occasion. It does nothing.)
> Hmmm.
> >
> > 2) I've never experienced dark-hardening. Where I live in the Midworst,
> > it's been extremely humid. I'm still developing prints I coated
yesterday -
> > no problem. They behave just like the prints I develop in the crispy
> > winter.
> >
> Well, there goes humidity as a reliable contributor to the dark
> reaction. I thought that one at least was a keeper.
> kt
Received on Wed Jun 16 09:02:48 2004

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