Re: dichromate stain

Errr... This is bad news - especially when reading it while holding the
guache white paint I purchased to make a one coat gum on black Fabriano
cardboard (using a positive). Because the label says PW6/PW5 (a mixture of
"Titanium Dioxide" and "Coprecipitate of zinc sulphide and barium sulphate")
I hope PW5 is different from the zinc white you're referring to (could your
"zinc white" be PW4?).

Regards,
Loris.

----- Original Message -----
From: "Katharine Thayer" <kthayer@pacifier.com>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Thursday, June 17, 2004 2:11 PM
Subject: Re: dichromate stain

> Sorry, another clarification:
>
> Katharine Thayer wrote:
> >
>
> >
> > (2) One thing I learned yesterday is that zinc white gouache in two
> > different brands with two different gums caused dichromate stain every
> > time. I also learned from handprint.com that zinc white blocks UV below
> > 370. So I guess I would say that this is the first pigment that I've
> > found, at least in gouache formulations, that probably doesn't work very
> > well for gum.
>
> To be clear, this should read "this is the first pigment I've found that
> I would say probably doesn't work very well for gum, at least in gouache
> formulations."
Received on Thu Jun 17 12:29:57 2004