Even if you don't know what paint "alligatoring" is, you've probably seen it. Maybe you've even wondered if it's more likely ...

“These pigments were selected for their extensive use in the artistic field through history and because they differently affect the curing and ageing of an oil paint layer,” the researchers say.

Over time these react with negatively charged components of oil called fatty acids, which have been severed from the rest of the oil molecules by light, heat and humidity. This process, known as ...

and the paint and glue layers had separated after the artwork hung for several years on a damp wall. In such circumstances, Mayern wrote, a canvas required a foundational layer of lead-rich oil.