ASIO made sure they covered every day, usually three, of every National Congress of the Communist Party of Australia from the early 1950s. These were a valuable guide to who was active in the party. One Congress the 1958 event even had sound added later with a narrator noting the identity of each person as they appeared. These films would be shown to ASIO officers regularly so that they got to know that faces of as many Persons Of Interest as possible. These events were important enough to invest significant money - photographic teams were expensive - into. Here even on Day 3 they end up with 30 minutes of film.