A question of preservation: A swath of spandex fabric with Day Glo pink graffiti designed by Stephen Sprouse. Indianapolis Museum of Art at Newfields, Gift of Joanne Sprouse, in memory of her son Stephen Sprouse, 2020.42.

“For artists, the effect isn’t simply cosmetic, because they intentionally use these colors for their visual impact,” said Sarah Schmidtke Sobeck, a photochemist at The College of Wooster. Sobeck and Gregory Smith, a conservation scientist at the Indianapolis Museum of Art, have collaborated on researching such materials for a decade. Their earlier work showed that optical brightener compounds degrade faster than pigment dyes, causing colors to darken even without pigment degradation.

This poses a challenge for conservationists, who must match colors under visible and UV light while pigments change over time. The team’s latest research extends to glow-in-the-dark phosphorescence pigments, focusing on the museum’s Sprouse collection. Early findings show these materials have a different composition—mineral-based pigments and inorganic compounds—and humidity is a significant factor in their breakdown, affecting storage and exhibition practices.

Next, the project will test lithopone, a white pigment powder, to see how long phosphorescent materials containing it glow after each charge.