Guardians of the Formula, a film partly shot in Slovenia in which Serbian director Dragan Bjelogrlić depicts the long-kept secret about experiments to build an atomic bomb in the former Yugoslavia, opened the Ljubljana International Film Festival (LIFFe) on 8 November to receive a standing ovation.

A co-production of Serbia, Slovenia, Montenegro and North Macedonia, the film was inspired by the true story about the "Serbian Chernobyl", depicted in the 2017 novel Slučaj Vinča (Vinča Case). In the 1958 incident at the Vinča Scientific Institute six young researchers were exposed to radiation.

Addressing the audience, Bjelogrlić said that little had been known about the incident, most of the documentation had disappeared and witnesses were reluctant to come forward. In adapting the story for the big screen, he was particularly interested in how the formula of death can become the formula of life.

His film, subtitled Chain Reaction, shows how after the incident the six researchers from the Vinča institute, mostly physics students, are flown to Paris for treatment, which eventually leads to the first successful human bone marrow transplant from unrelated donors by French doctor Georges Mathe.

Serbian director and actor Dragan Bjelogrlić at the opening of the Ljubljana International Film Festival. Photo: Katja Kodba/STA

"If any of the audience members think this is a fairy tale, they should remember that it is a true story," Bjelogrlić, who also appears in the film himself, told the packed audience at Cankarjev Dom.

The film was shot for a good two months, including in Škofja Loka and Ljubljana in Slovenia. Nuclear experiment scenes were shot at the nuclear reactor of the Jožef Stefan Institute.

The theme song for the film was written by Slovenian musician Magnifico in collaboration with Konstrakta, best known as Serbia's 2022 Eurovision Song Contest entrant. The film also features Slovenian actor Jurij Drevenšek.

The opening ceremony heard that LIFFe has a faithful audience of between 40,000 and 50,000 people. In the past 33 editions of the festival, more than one million people saw almost 2,000 films at around 6,000 screenings.

This year a total of 89 feature films and 14 shorts will be screened at six venues in Ljubljana as well as in some other cities across the country until 19 November. Some 30 filmmakers will make their appearance in person.

Apart from this year's winners of all major European film festivals, and the latest from major auteurs, the festival also brings films by up-and coming directors which are vying for the Kingfisher, the festival's main prize. There will be a special section on contemporary Argentinian cinema and one dedicated to Italian political film.