Under normal light, the Grueby vase looked flawless — a rich cucumber matte glaze, crisp leaf modeling, no visible chips or cracks. Under the ultraviolet lamp in Elena Rojas‘s lab in Culver City, it lit up like a roadmap. Three separate areas of fill and inpainting fluoresced bright purple against the dull green of the original glaze.
“This piece had been professionally restored, probably 20 years ago,” Rojas said. “Under daylight, you’d never see it. Under UV, it’s obvious.”
Ultraviolet fluorescence imaging exploits the fact that original ceramic glazes and modern restoration materials respond differently to UV light. Original glazes, fired at high temperatures, tend to fluoresce in muted, uniform tones. Epoxy fills, acrylic inpainting, and modern adhesives fluoresce in distinctly different colors — typically bright blue, purple, or white.
Rojas uses a modified Nikon D850 with a UV-pass filter and a pair of 365-nanometer LED panels in a darkened room. The camera captures what the eye cannot see, and the resulting images are often startling.
The technique is not new in fine art conservation, but its application to the decorative arts market is gaining traction. Martin Greif, a dealer in American art pottery based in San Francisco, said he now requires UV documentation on any piece priced above $5,000.
“Five years ago nobody asked,” Greif said. “Now, if you can’t show me a clean UV image, I assume there’s a reason.”
Rojas estimates that roughly 30 percent of the high-end pottery she examines shows some level of undisclosed restoration. She is careful to distinguish between deliberate fraud and honest ignorance — many sellers, she says, simply do not know their pieces have been repaired.
Her lab, Rojas Conservation, offers UV imaging reports starting at $150 per object.