B
ut there are chinks in the non-toxic
edifice. Departing from the Levison
legacy, Liquitex® explains why it won’t
reveal the pigments in their Cd-free
paints: “Given the innovative natural
and high investment in research and
development, we have decided not
to share the pigment details in our
Liquitex® cadmium-free colors. We
think of it as our ‘secret code.’” 4
Sometimes in a highly competitive
market “The real reason for secrecy is
the need to conceal the fact that there
is nothing to conceal.” 5 There are only
so many pigments that could be put
together to match the look and feel of
real cadmiums. But there is another
dimension not often considered. The
paint may carry a certified non-toxic seal
but what about the industrial processes
involved in making it?
A look at one highly non-toxic pigment
may illustrate the conundrum. Titanium
white (titanium dioxide [TiO 2 ]) is the
brightest of all white pigments and
indeed the only one in nearly all the
paints in the paint store (which are
colored with universal colorants.) Its
production only began in 1918 and
could not be carried out on less than an
industrial scale because of what it takes
to extract titanium metal from the ore and
process it. By 2014, global production
had risen to 6,564,000 metric tons, and
was still growing. In addition to its use
in coatings, titanium white is also used in
the production of paper, plastics, glass,
ceramics, cosmetics, and other personal
care products, including toothpaste. It is
non-toxic because it is chemically inert.
Of the two methods used today, 6 one
requires huge quantities of sulfuric acid
and leaves massive amounts of waste
products; the other involves chlorine gas
and coke, derived from petroleum or
coal, and also leaves toxic byproducts.
How “safe and sustainable” these other
industries are or can ever be remains an
open question.
Prior to the Industrial Revolution the
number of artists’ pigments was very
limited. Their manufacture was much
simpler and they were made on a much
smaller scale.
The only suitable white for oil painting
was white lead: basic lead carbonate
(2PbCO 3 ·Pb(OH) 2 ). White lead is
chemically reactive and for that reason
has an advantage over other white
pigments used in oil painting — it forms
felicitous chemical bonds with fatty
acids in the drying oil, becoming part
of the polymer architecture of the paint
film. This bonding is a significant factor
in the preservation of Old Master oil
paintings.
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