WWW.ASTRONOMY.COM 51it only f lirted with his still-
evolving Pointillist style. Still,
one can see in the sky the
smoggy effects of air pollution
from the industrial chimneys in
the distance, giving testament to
his pursuit in capturing realistic
atmospheric optical effects.
A turning point came in the
summer of 1884, when Seurat
showed the work at the first
exhibition of the Group of
Independent Artists, of which
he was a founding member.
That summer he met with
younger Neo-Impressionist
artist Paul Signac, who pointed
out to Seurat that Bathers
lacked the luminosity of other
Impressionist paintings — the
result of his use of muddy earth
tones rather than colors of pris-
matic purity. As Catton Rich
notes in his 1958 book, Seurat:
Drawings and Paintings, Seurat’s
next monumental work — A
Sunday Afternoon on the Island
of La Grande Jatte (18 8 4) —
“explore[s] to the fullest the new
laws and principles which he
and Signac were developing.”
Seurat preferred to call his
new technique “color-luminism”
(chromoluminarism), because it
gives a painting not only a
greater sense of vibrancy but
also a shimmering effect, like
one experiences on a hot sum-
mer’s day as heat rises from a
roadway or sidewalk.
Volcanic influences?
Seurat’s use of the technique of
chromoluminarism coincides
with the optical effects trail-
ing the August 1883 eruption
of Krakatau. It seems almost
impossible that Seurat and his
fellow optical science-oriented
artists of the Neo-Impressionist
movement would have ignored
the profound post-Krakatau
skies — especially because the
resulting atmospheric optical
effects created the most chro-
matically vibrant skies recorded
for a century. And the vibrancy
of light was key to the new
artistic movement.
But the Krakatau aerosols
also performed light magic in
the daytime sky, generating dif-
fuse aureoles of complementary
light that radiated most effec-
tively at high noon. Such a sight
would have had the capacity to
inspire Seurat, especially con-
sidering that the artist was keen
on the science of diffraction and
Rayleigh scattering. It would
also be appropriate to suggest
that the daytime sky, as painted
by the Krakatau eruption, stood
before the Neo-Impressionists
like a visual muse, inspiring
new insights into color and tone
that perhaps only science-
inspired artists could fully
appreciate.
X-ray imaging of Bathers at
Asnières reveals that Seurat mod-
ified parts of it in the mid-1880s,
adding prismatic colors in a
Pointillist manner that creates
a more vibrant feel.
Bathers had not quite beencompleted by the time Krakatau
erupted in August 1883, and the
volcano’s associated atmospheric
effects only became vividly
pronounced over Europe by
November of that year. But its
optical effects remained intense
at least until 1887, and skywatch-
ers continued to record volcanic
atmospheric effects to a lesser
degree into the early 1900s.
Vo l c a n i c s k i e s , t h e n , w e r e
present throughout the brief
heyday of the French Neo-
Impressionist movement, which
f lourished principally from 1886
to 1906. To understand how these
optically vibrant skies may have
affected Neo-Impressionist
thinking, let’s fast-forward
100 years to 1983, the year El
Chichón erupted in Mexico.ABOVE: English artist
William Ascroft made these
three crayon sketches
on the banks of the
Thames in London. They
show color shifts in the
western sky after sunset
November 26, 1883. The
colors were created by
the interplay of light with
stratospheric volcanic
aerosols, which circled the
globe after the August 1883
eruption of Krakatau in
Indonesia. STEPHEN JAMES O’MEARA