Pigments (was: Re: Why Winsor & Newton?

From: Katharine Thayer ^lt;[email protected]>
Date: 06/01/05-11:54:36 AM Z
Message-id: <429DF64D.2D47@pacifier.com>

Hi Eric,
Just to make sure we're on the same page-- pigments have of course been
widely tested for lightfastness for many years. The American Society of
Testing and Materials provides lightfastness ratings for all pigments.
It is these ASTM ratings, supplemented by data from independent testers
like Bruce MacEvoy and Hilary Page, which give us good information as to
whether a pigment, and more specifically a particular watercolor paint
made from that pigment, is lightfast or not. So that part, the
lightfastness of individual pigments and paints per se, is pretty well
established. Sure, there are slight discrepancies between the ratings,
but they are usually not great. For example, the paint we were
discussing this morning, the Holbein "opera" -- there's no one claiming
that this paint is absolutely lightfast. The discrepancy is between one
tester claiming that the paint is good to use in spite of not being
absolutely lightfast, and another saying that the paint is fugitive
enough that it shouldn't be used in collectible art work. I prefer not
to use any pigment where there's been a question, but other gum printers
of course are free to make their own decisions on this issue.

What's not known is whether being encased in gum provides some
protection for fugitive pigments, allowing them to fade less. As I said,
I'm skeptical, but here we're out in uncharted territory. But I should
hasten to say that very many pigments are perfectly lightfast, and if
people stick with those they shouldn't have any problem with long-time
permanence of their prints. The only question is about the less
lightfast ones. As paint manufacturers are gradually phasing out the few
fugitive pigments that have held on in watercolor paint, like indigo
(PB66) van dyke (PBr8) alizarin crimson (PR 83) gamboge (NY24) etc,
the problem of people inadvertently selecting fugitive pigments because
they like the color or whatever will become less and less of a problem
as time goes on. The more important point being that if people are
careful to pick lightfast pigments, they should never have to worry
about the permanence of their gum prints.

As to Wilhelm, the only mention of pigments in the book refers to
UltraStable and EverColor processes. I don't know what testing they've
done of these processes since the book came out, but at any rate they
don't reveal the pigments, probably due to proprietary concerns. The
book says rather cryptically, "The initial UltraStable materials,
introduced in 1991, used a non-toxic organic yellow pigment that proved
to be significantly less stable in light fading tests than expected
based on data provided by the pigment manufacturer. New materials made
with a more stable, lead-free, metal-type yellow pigment were introduced
in late 1992, but test results for the new pigment were not available
when the book went to press." One can guess what those pigments might
have been (and didn't I hear that one or both of those companies had
gone out of business since then?) but I wouldn't spend a lot of time
trying to determine what they are, since we already know a bunch of good
lightfast yellow pigments to use.

I guess the real question is, why would people insist on using pigments
known to be fugitive when there are so many lightfast pigments available
in all color ranges? Now if people don't care whether the pigment is
lightfast or not, that's one thing. My purpose in educating people on
pigments is so that people have the information; if they then choose a
fugitive pigment, they are at least making an informed choice.
Katharine Thayer

Eric Neilsen wrote:
>
> Has he tested any of the pigments? They are used over a broad range of
> mediums and serious collectors would want to know. Curators should be
> looking for this information as well or do you think that they just wait
> until it fades? Perhaps, Bob has some info on that as he has toured several
> plants? Are any of these same pigments being used in the ink jet industry?
>
> Now pt/pd printing doesn't seems so full of problems : )
>
> Eric Neilsen Photography
> 4101 Commerce Street, Suite 9
> Dallas, TX 75226
> 214-827-8301
> http://ericneilsenphotography.com
> > -----Original Message-----
> > From: Katharine Thayer [mailto:kthayer@pacifier.com]
> > Sent: Wednesday, June 01, 2005 7:52 AM
> > To: alt-photo-process-l@sask.usask.ca
> > Subject: Re: Why Winsor & Newton?
> >
> > Eric Neilsen wrote:
> > >
> > > Where is Wilhelm in all of this? Has he tested any of the pigments
> > applied
> > > as "intended" or within a gum print?
> >
> > Don't I wish! But I don't think so..... it seems unlikely that they
> > would be interested in this, as so very few people are involved with gum
> > printing.
> > kt
> >
> > >
> > > Eric Neilsen Photography
> > > 4101 Commerce Street
> > > Suite 9
> > > Dallas, TX 75226
> > > http://e.neilsen.home.att.net
> > > http://ericneilsenphotography.com
> > >
> > >
> > > > -----Original Message-----
> > > > From: Katharine Thayer [mailto:kthayer@pacifier.com]
> > > > Sent: Wednesday, June 01, 2005 6:04 AM
> > > > To: alt-photo-process-l@sask.usask.ca
> > > > Subject: Re: Why Winsor & Newton?
> > > >
> > > > Katharine Thayer wrote:
> > > > >
> > > > > Christina Z. Anderson wrote:
> > > > > >
> > > > > > > Christina Z. Anderson wrote:
> > > > > > > Now, Holbein does have one color that no other person makes
> > quite
> > > > > > >> the same--Opera. Can't wait to make a gum with that as my
> > magenta
> > > > of
> > > > > > >> choice.
> > > > > > Katharine wrote:
> > > > > > > Just so you know, one of the pigments in that paint, basic
> > violet
> > > > 10, is
> > > > > > > fugitive. (The other pigment is PR122, quinacridone magenta).
> > > > > >
> > > > > > Interesting, but Page gives it 3 stars, her highest rating, saying
> > > > > > lightfastness is very good.
> > > >
> > > >
> > > > And as I was saying in a conversation with Henk last week or so, no
> > one
> > > > really knows for sure whether pigments that are fugitive in themselves
> > > > are equally fugitive once encased in hardened gum. I assume that the
> > > > answer is yes, so I don't use fugitive pigments. But until someone
> > > > actually does that fade testing, we're all just guessing; maybe
> > you'll
> > > > do those tests, Chris...
> > > > Katharine
Received on Wed Jun 1 18:50:18 2005

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