Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp with lithophane porcelain inserts (1860–79) (Museum Catharijneconvent, via Wikimedia)

Imperceptible in the light, only when illuminated by flame in the dark is a 19th-century lithophane image revealed. A series of photographs demonstrating this often overlooked imaging process, where very thin porcelain displays a hidden three-dimensional imprinted image only when backlit, were recently added to Wikimedia Commons by the Museum Catharijneconvent in Utrecht, Netherlands, south of Amsterdam.

The lithophanes are part of over 2,600 high-resolution images contributed from the museum’s collections, which focus on religious art dating back to the Middle Ages and Dutch paintings from the 16th and 17th centuries. There’s also a silver memento mori casket from the 18th century, a clay monk with stigmata emerging from the mold that made him from the 15th century, and a stunning early 17th-century reliquary still holding some saintly remains attributed to St. Willibrord.

The Museum Catharijneconvent lithophanes are illuminated in an 1860–79 cast iron frame with an embedded lamp, the light radiating through religious scenes, such as the Holy Family journeying by donkey and the luminous Christ Child. Lithophanes were sometimes used to decorate lamps, as portraiture, and in stained glass. With their discrete nature they even on occasion were designed to reveal clandestine erotica when held up to a flame. Although obscure, they’re not completely forgotten, as a small museum is devoted to them at the Toledo Botanical Garden in Ohio, and some people are reviving the technique with 3D printing. You can see the Museum Catharijneconvent lithophanes below, and explore hundreds more of the museum’s objects now in the public domain of Wikipedia.

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp with lithophane porcelain inserts (1860-79) (Museum Catharijneconvent, via Wikimedia)

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp without the lithophanes, with the lamp area revealed (1860-79) (Museum Catharijneconvent, via Wikimedia)

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp with lithophane porcelain inserts (1860-79) (Museum Catharijneconvent, via Wikimedia)

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, via Wikimedia)

Detail of one of the lithophane porcelain inserts (1860-79) (Museum Catharijneconvent, via Wikimedia)

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp with lithophane porcelain inserts (1860-79) (Museum Catharijneconvent, via Wikimedia)

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp without the lithophanes (1860-79) (Museum Catharijneconvent, via Wikimedia)

Cast iron oil lamp with porcelain inserts (1860-79) (Museum Catharijneconvent, Wikimedia)

Cast iron oil lamp with lithophane porcelain inserts (1860-79) (Museum Catharijneconvent, via Wikimedia)

View all of the over 2,600 images from the Museum Catharijneconvent on Wikimedia Commons.

Allison C. Meier is a former staff writer for Hyperallergic. Originally from Oklahoma, she has been covering visual culture and overlooked history for print and online media since 2006. She moonlights...