The world lacks a great all-around red. Always has. We’ve made do with alternatives that could be toxic or plain gross. The gladiators smeared their faces with mercury-based vermilion. Titian painted with an arsenic-based mineral called realgar. The British army’s red coats were infused with crushed cochineal beetles. For decades, red Lego bricks contained cadmium, a carcinogen.
More than 200 natural and synthetic red pigments exist today, but each has issues with safety, stability, chromaticity, and/or opacity. Red 254, aka Ferrari red, for example, is safe and popular, but it’s also carbon-based, leaving it susceptible to fading in the rain or the heat. “If we sit out in the sun, it’s not good for us,” says Narayan Khandekar, director of Harvard’s Straus Center for Conservation & Technical Studies and curator of the Forbes Pigment Collection. “That’s the same for most organic systems.” One red is stable, nontoxic, and everlasting: iron oxide, or red ocher, the ruddy clay found in Paleolithic cave paintings. “It’s just not bright in the way that people want,” Khandekar says.
I imagine that back at my parents house there are a few buckets of highly toxic old Legos. Who knew red was so difficult?