It would be easy to pass by this East London church without realizing there’s a delightful collection of ceramic eggs painted with clown faces on display in the back room. This is the Clown Egg Register, a quirky way of immortalizing the unique faces of professional clowns.

This wonderfully odd archive includes more than 250 painted eggs, though only about 50 of them are currently on display at Holy Trinity church in Dalston, home to the Clowns’ Gallery-Museum, run by Clowns International.

When a new member registers with the organization, a replica of their personal makeup design is carefully painted onto a ceramic egg and added to the register. Clowns help this tradition along by sending photos of their made-up faces and swatches of fabric from their costumes. The archive acts as a sort of non-legal but understood copyright, to make sure each clown has a distinct look, and no two clowns are too similar.

The practice started in 1946 by a member of Clowns International (then called the International Circus Clowns Club), Stan Bult, who painted the clown faces on emptied-out chicken eggs as a hobby. It evolved into a useful record of faces for posterity, as well as a way to memorialize the great clowns of yore.

Bult painted around 200 eggs in total, and while most were lost and broken over years, 26 of these fragile originals can be found at the church in Dalston, along with another 46 clown eggs on permanent display. This back cabinet of painted eggs caught the attention of photographer Luke Stephenson when he stumbled on the Clown Egg Register in 2007. He published a book of his fantastic photographs of the eggs, taken from both locations of the collection.