What Painting Is: How to Think about Oil Painting ... - Victoria Vesna

70 THE MOULDY MATERIA PRIMA
solutions varying in concentration from 1–0.025%. With the
more dilute solutions, the suspended threadlike precipitate
and purple color were observed, but the amount of
precipitate was insufficient to cling to a stirring rod. With
the more concentrated solutions, enough precipitate was
obtained to cling to a stirring rod, but it was brown or black
and quickly deposited on the bottom of the test tube.
In all cases the tubes must be allowed to stand for several
weeks for development of the “slug,” which is apparently a
mold impregnated with colloidal metallic gold. We have
had the fungus, which also grew in the tannic acid stock
solution, tentatively identified as either Penicillium
frequentans (P. tannophilium) or Penicillium spinulosum (P.
tannophagum), both of which are reported to decompose
tannin and tannin liquors and from which the enzyme
tannase has been produced.
It is a disappointing result, this golden creature that turns out to
be nothing but a clot of mould. But it is also entirely in the spirit
of alchemical and artistic experiment. The alchemists were drawn
to slag and refuse: they loved the suspicious skins that thickened
over their stews. They rooted in cinders and picked at ashy
heaps. They let their waters rot, and then rummaged in the soft
granular sludges that sank to the bottom. More often than not, it
is the crust or the ash that fascinates them, and not the pellucid
colors and volatile oils that comprise the stew itself. Putrefaction,
with its Latin name putrefactio, is a nearly universal step in the
alchemical work. The clean substance has to degenerate into
brackish mould before it produces anything worth examining.
Academic painting had a natural affinity with mud and
excrement, because of the common use of brown hues and thick
varnishes that yellowed and darkened with age. The
Impressionists laughed at the academics’ “brown sauce,” but
William Blake had already put it best when he said Rubens used
“a filthy brown, somewhat the color of excrement.” From the
mid-sixteenth to the mid-nineteenth century, paintings were
routinely founded in “earth tones,” and it was only a step to go
from speaking about “muted colors” to acknowledging what the
paint was really like: sluices of mud, running diarrhea. (Another
name for the materia prima was terra fœtida, “fetid earth.” 2 )
Impressionist and Postimpressionist canvases are acts of