Historically, lead-based white was the pigment used in art, for hundreds of years. But of course, lead is toxic and lead white has been largely outlawed in Europe, now almost nonexistant in the US. Zinc white was introduced as an alternative, was popular for a while, but then caused de-lamination in paintings. Currently, titanium white is the most popular white pigment found in artist paints. Titanium dioxide, the white ingredient in toothpaste and sunscreen, is bright, opaque, and has been generally regarded as non-toxic. But recently, artist paint manufacturers have started posting warning labels on tubes of titanium white!
It seems that nano-particle “engineered” versions of titanium are at the root of the problem, and they are finding their way into all areas of public consumption, including artist paints. Studies are showing that low levels of ultraviolet light, as found in nature, can cause titanium dioxide nano-particles to become highly toxic to marine phytoplankton, the most important primary producers on Earth. Eventually these particles could be the next big occupational or environmental concern for the planet.
Artists need a better white!