Have you noticed the display cases in the foyers at Arts Centre Melbourne (ACM)? Usually filled with costumes from productions past, they might also contain other performing arts treasures such as set models or design sketches. Perhaps you have visited the Australian Music Vault, a small permanent exhibition in ACM’s Theatres Building that explores the local popular music scene’s history, from guitars to posters.

The Australian Museum of Performing Arts’ DIVA collection. Photo supplied

If you didn’t know that the displayed items are a fraction of the Australian Performing Arts Collection’s 850,000-plus objects, you’re not alone. “This collection is a big, best-kept secret,” says ACM’s Head of Curatorial, Margot Anderson. She admits that’s been frustrating since her work on it began as a volunteer in 1999; not only personally frustrating, but also because of her sense of obligation to artists and companies represented by the collection, which mostly comprises their donations.

It won’t be secret much longer. Opening on 11 December, the Australian Museum of Performing Arts (AMPA) is the Centre’s dedicated exhibition space for displaying more of the collection and telling more stories about the nation’s rich theatre, dance, opera,...