From: Katharine Thayer (kthayer@pacifier.com)
Date: 04/19/03-02:41:40 AM Z
Comments embedded in several places below:
Judy Seigel wrote:
>
> On Wed, 16 Apr 2003, Katharine Thayer wrote:
>
> > ... A particular pigment, with a particular
> > number, has a particular chemical composition and as a result,
> > particular properties and characteristics. There are very few
> > manufacturers and purveyors of pigments in the world; the difference
> > between a particular pigment from one manufacturer or another is like
> > the difference between table salt labeled with the Morton's brand and
> > table salt with some other brand name on it....
>
> Aside from the fact that different salt brands have different ingredients
> (iodides added or not, and some with starch to prevent sticking, that we
> know of, and whatever it is about "sea salt" called for in various
> recipes) pigment is a more complex compound than sodium chloride. Which
> is to say, the analogy does not hold. It doesn't hold in theory and IME it
> doesn't hold in fact.
I already addressed this, on Wednesday, but here's my answer again in
case it didn't find its way to your mailbox:
"My analogy
wasn't intended so much to suggest that examples of the same pigment
from different sources are as exactly alike as table salt from different
sources, as to make the general point that the same pigment from
different sources, like table salt from different sources, is much more
alike than it is different. In other words, no matter where it comes
from, sodium chloride is sodium chloride, and burnt umber is burnt
umber. Each pigment has its own particular characteristics and
appearance that is immediately recognizable to any artist who has spent
time with colors, and while there may be differences in color and
handling between the burnt umber from different purveyors and packaged
by different paint manufacturers, those differences hardly outweigh the
similarities, nor can they change the fundamental identity and
functionality of the pigment, which are determined by its chemical
composition. Not all bald eagles look exactly alike, not all great blue
herons look alike, not all peregrine falcons look alike, but when I see
a bird a mile off, I can tell just by how it flies whether it's an
eagle, a heron or a peregrine"
> When I tested some 8 brands of burnt sienna, all supposedly bona fide
> burnt sienna, all from major manufacturers, American and European, I found
> no two exactly alike. (There were in fact more manufacturers, but I got
> tired of the game.) Most were distinctly different colors, and exposed and
> developed differently, printed with different densities, and showed a
> different number of steps, even with all other variables the same.
It seems different issues may be getting confused here, as often seems
to happen in these discussions. I was making a point about being
specific about pigments, pointing out for example that gamboge, NY24,
is a fugitive pigment, but a lot of paints called gamboge aren't really
gamboge. My goal was to get people to pay more attention to pigments
than to color names, because pigments have fundamental characteristics
(lightfastness, opacity, etc) based on their chemical composition. Just
because two paints have the same name doesn't mean they have the same
pigment in them, was my point, so it would be helpful when we talk about
colors to be specific: either use the pigment name and number, or better
yet, the specific brand and paint number. Otherwise we can be talking
about apples and pears.
Although I was arguing that each pigment has a particular "profile"
including its appearance, general behavior, fundamental characteristics
like fading etc, I certainly have never argued that all brands of burnt
sienna, for example, print exactly alike; in fact I've argued quite the
opposite, that no generalizations can be made and one must learn how a
particular paint prints, since they are all different. I think perhaps
the discussion about pigment characteristics and pigment specificity
somehow got confused with the discussion about whether you can say how
much paint to use per how many ml gum; I'm sure we all agree that you
can't. The question about pigment characteristics is a more general
question; it has to do with whether the bird is an eagle or a heron. How
the particular brand prints is a more specific question: knowing that
these two birds are both eagles, how are they different?
> > As to all the fillers and extenders and whatnots, you find
> > those more in the student grades and other lesser types of paint; most
> > fine artist quality paints have little or none of this gunk in them and
> > tend to be pure gum and pigment, sometimes with honey added to retain
> > moisture, but otherwise no extra stuff.
>
> Again, this is said with great authority, but is not my experience. I
> have for instance found distinct differences in "major" brands of
> so-called "artists' water colors" in covering power (presumably although
> not necessarily pigment concentration) and staining (presumably dispersal
> or other "agents"), not to mention such other behavior as the "reverse
> ladder" noted previously.
I know that the brands I use, Daniel Smith and M. Graham, do not use
fillers or extenders in their paints. Stephen Livick insists that the
brands he recommends, the Linel line from LeFranc and whatever and
Sennelier, don't use fillers and extenders in their paints. Yes, each
paint is different, I've never argued otherwise. I'm not sure what the
argument is here because I think we agree on the basic point, that
paints are different. To sum up: Table salt is different from red
pepper; eagles are different from herons; burnt sienna is different from
cadium yellow. Table salts differ; eagles differ; burnt siennas
differ.
Katharine
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