From: Judy Seigel (jseigel@panix.com)
Date: 09/17/03-03:15:00 PM Z
Sorry I didn't get back on this sooner, but reality intervened, as it so
likes to do. I return to the point, however, because the longer the world
believes that Indanthrene is indigo, the harder the notion will be to
dislodge from the collective brain and the more it will defy correction
(as per the so-called Gum Pigment Ratio test which, after 3/4 of a
century, WILL NOT DIE!).
I assume Katharine got the notion that Indanthrene is indigo by surmise
from, or even assertion of, a recent watercolor pigment book, the title of
which I forget, by a woman whose name I also forget, although it is surely
not 20 feet from where I sit, possibly under a piece of laundry or other
loose detritus (proving again, if proof be needed, that it can take an
instant to put something "away" & a lifetime to find it).
But I beat about the bush, sorry. (I'm rattled by this loss & if someone
will kindly tell me the wording of the title, and the color and dimensions
of the book, I'll try again.) Meanwhile, I refer to Mayer, Doerner, Wilcox
and Delamare & Guineau on the topic. I said "real Indigo is no longer
available," or wowrds to that effect, nor is it.
To quote Ralph Mayer (whose "The Artist's Handbook" was the bible until
acrylic took the field), indigo was,
"A deep transparent blue originally obtained from plants cultivated in
India. A better grade has been made synthetically from coal tar since the
end of the 19th century. It is not entirely light proof & has long been
discarded as a permanent artists' color. [Indigo] was used in Europe from
early times, principally as a dyestuff."
My copy of Mayer, dated 1957, does not mention Indanthrene, although my
Doerner, dated 1940, does, leading me to surmise (perhaps falsely) that
Indanthrene was a product of the German synthetic dye & pigment industry,
which prevailed in the early 20th century until it was discombobulated by
WWI. When I painted in oils, Max Doerner's "The Materials of the Artist &
Their Use in Painting with Notes on the Techniques of the Old Masters"
drove me crazy for digressivity and lack of clarity, seeming not quite
translated from the German. But now that I'm not trying to learn
undercoats, grounds & sizing, et al, it seems just pleasantly chatty.
Doerner calls natural indigo "impermanent" and "entirely superfluous." His
brief comment that "at least today" we have "Indanthrene blue GGSL for
Prussian blue" suggests that the color was relatively recent.
My 1991 Wilcox "Guide to the Finest Watercolour Paints" spells it
Indanthrone, color index name PB 60. "A slightly dull blue, leaning a
little towards violet. Semi-opaque, it has poor covering power unless
applied rather heavily." He rates it ASTM I in both oil & acrylic, but,
"without the binder it might not rate as highly in watercolour."
Wilcox also says "genuine Indigo" is now obsolete in artists' paints. A
synthetic version introduced in 1897, PB 66, "deteriorated badly." It's
also called "CI Vat Blue 1 Dye." He shows 13 contemporary brands of
watercolor paints NAMED "Indigo." Most with good ratings are based on
thalo; only one is based on "Indanthrone" -- from Lefranc & Bourgeois. It
rates 3 out of a possible 4, & II for lightfast (I is highest). I assume
the ones Katharine cited are later developments, or otherwise omitted from
this Wilcox.
But if you've read thus far, reward yourself with a wonderful little book,
"Colors: The Story of Dyes and Pigments" by Francois Delamare and Bernard
Guineau, only $13 from Kremer [Discovery/Abrams], charmingly illustrated
in full color, a gem for the library of any artist. It leaves us in humble
awe of the achievements of artists whose colors were brought by caravan,
trader, shipwreck and warlord from India or other remote sources, then
excruciatingly processed. We learn why colors acquired certain uses and
meanings, and the devastating effects of growing dyes on the soil, as well
as on the economy & the workers. From the cave to Josef Albers, plus
bibliography. (The index, BTW, has 20 entries for indigo, none for
Indanthrene or -throne.)
Judy
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