> it could be, how do you say it a load of flapdoodal
Well, as ever you're a day ahead of us in England, it being still Friday
afternoon here... and tho I appreciate the attempt to speak English --
this important word is spelled "flapdoodle," as in yankee doodle.
> >I have a brochure from an American company, Gamblin, which as I recall
> lists another new synthetic yellow. I think I can locate this brochure.
In this promise I was mistaken. As of current writing I have not located
the booklet, which wasn't in the "pigment" folder, the "company catalog"
folder, the "supplies" folder or the "college art" folder. There's no
mystery about this, as it is well known that beings from another galaxy
slip in under cover of darkness and, using their telephathic powers to
foretell what you will need next, bury it under your 1989 income tax
receipts.
I did however easily locate the Kremer booklet, as it was out on the
piano. Under "Yellow/Orange Pigments, Organic Manufactured," it has the
following note:
"Organic manufactured pigments are synthesized from organic chemicals.
They are usually bright, light in weight and transparent. We have
selected the most lightfast pigments from the hundreds available today"
Among the various yellows listed (a couple of them called "Hansa") are
"Permanent Yellow Light, plain and Medium, and Arylide Yellow, which is
described as "bright yellow, high tinting."
A 20-gram jar of the Arylide (with dispersal agent added, doesn't work for
gum) is $4.60. 100 grams Arylide dry pigment is $11.95.
A note about "anorganic manufactured pigments" says colors containing
metals are "usually opaque", which I believe would include the cadmium
yellow I believe it was Bernie mentioned...
This is a branch of Dr. Georg F. Kremer, Farbmuhl, Aichstetten, Germany,
phone 011.49.7565.1011, fax 7565.1606.
IN NYC 228 Elizabeth ST, phone 212/219-2394, fax 212/219-2395.
And tho my search for the Gamblin booklet was frustrating, it put in my
hands another fine item, an article titled "Factors Influencing the
Wash-Fastness of Watercolours" by Vincent Daniels, from "The Paper
Conservator 19, 1995, sent to me by a kind friend.
This is a wonderful, frustrating & humbling essay -- frustrating because
its main thrust is for conservators, not gum printers, and the pigments
mentioned are only Winsor Newton, humbling because it hints at vast realms
beyond one's (at least this one's) personal ken, but wonderful because it
confirms our wildest gum paranoia -- for instance, that colors may be
washfast to different degrees on different papers.
Here's an example:
"Most pigments have a broad range of pigment sizes and synthetic organic
pigments and carbon black particles are sometimes as small as 0.01u in
diameter. The ease with which particles stick to fibres increases as the
size of particle decreases. Jones reports that particles below about
0.2u are 'virtually impossible to remove from cotton cellulose except by
drastic mechanical action, and washing is difficult even with particles
as large as 5u.'"
[This is what I was trying to say about fine grinding with a ball mill.]
"Almost all watercolour paints contain a surfactant which helps to
disperse the pigment in the gum and subsequently over the paper. Pigment
particles naturally tend to aggregate and need mechanical action to break
them up. A detergent can coat each pigment particle with molecules which
change its electrical charge. This makes the individual particles
mutually repulsive, breaking up aggregates and giving them affinity for
water...."
There is another section, too long to quote, about some tests suggesting
that in some circumstances impurities are useful -- the purified gum became
insoluble more readily.
And so forth. I believe this is a British publication.
I don't think it has a whole lot of info to revolutionize gum printing,
but enough to show that our tendency to think things like "I'll get finer
grain with finer pigment" or the purest gum gives the purest prints are
simplistic.....
> If you could please pass on this information I would be most obliged I am
> still striving to do better.
Aren't we all...
Judy