Online catalogs shine a light into public galleries and museums, but art owned by private collectors often remains in the shadows. London startup Vastari helps exhibition curators penetrate this gloom and bring obscure art works to public attention.

Curators building temporary exhibitions often include work on loan from public and private art collections. These borrowed pieces help fill out narratives about particular artists, periods or themes, usually complementing work from the host institution’s permanent collection.

Then there are institutions like Bozar, the Center for Fine Arts in Brussels, which have no collections of their own. “We cannot do exhibitions without borrowing work,” says Sophie Lauwers, head of exhibitions. “We really need to have these relationships, to circulate in these networks and convince private and public owners to lend us work from their collections.”

This means a lot of legwork. Large corporate collections advertise their holdings, but most individual collectors are more discreet. Yet they like to lend their work, either for pleasure or the bump in value brought by public exposure.

Bernadine Bröcker, Vastari’s founder, saw this while managing a private gallery in London’s exclusive Mayfair district. “We lent a work to an exhibition about Edgar Degas at the Royal Academy, and we had some clients of the gallery who then said that they also had works that were very relevant, so why hadn’t they been contacted?”

She started to investigate. “I discovered that a lot of material was not being included in exhibitions because of lack of communication between the public and private sectors,” she recalls. “A lot of museums decide to borrow from other museums rather than from private hands because of how long it takes to research and find the pieces.”