“I never sell the entire production,” Mr. Duiveman explained. “We always keep all the principals. If I have 40 chorus members, I sell 30 and save 10. Anything that might be useful for a future exhibition — something from a famous singer, or a world premiere, or something that has a special material — those things I will keep. We build up our archive, but at some point we just have to say goodbye to some of them.”

Known for commissioning interesting, postmodern new work with collaborators such as the artists Anish Kapoor and William Kentridge and the director Peter Sellars, and with a history of both starkly minimalist and classical productions, the Dutch National Opera has an in-house department that builds hundreds of costumes a year.

The costume sales are incredibly popular — the 2,000 available tickets for this one sold out online in 37 minutes. Here is a tiny selection of the whimsical and fantastical costumes on sale, which date to the 1970s but were used in recent productions.

Frog with skippy ball