Wednesday, October 7, 2009

We Were Switched from Lead to Zinc White Because....

Everyone knows that lead white is poisonous and thus had to have been banned. So all the manufacturers of both common house paint and artists' paints switched to zinc whites. Now, there's no evidence that lead whites poisoned artists, but became dangerous in the modern era when used as house paint. Now a study from the Smithsonian Museum's Conservation Institute quoted by George O'Hanlon for Rublev Natural Pigments has bad news for artists using zinc whites. It becomes brittle and cracks easily after a mere 28 years.

The article concludes:
"Paints made with zinc oxide and drying oils become extremely brittle in as little as three years. Paints containing zinc oxide exhibit severe delaminating problems after drying and especially zinc oxide paint on acrylic emulsion grounds. Even commercial lead white and titanium white oil paints containing zinc oxide become quite brittle after seven years of drying ... Mecklenburg and Tumosa's paper forewarns us about the potential problems with oil paints containing zinc white commonly used by artists today. Artists may choose to ignore the report and continue using zinc in their paintings -- perhaps at their own peril. Whatever the choice, the paper helps artists gain a better understanding of the materials used in their work."

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