The film is "Herb and Dorothy" by Megumi Sasaki. It's a charming documentary about a married couple, who despite modest means — Herb was a postal clerk and Dorothy was a reference librarian at the Brooklyn Public Library — amass one of the most important contemporary art collections ever.
In 1992, the Vogels made headlines that shocked the art world: their entire collection was moved to the National Gallery of Art, the vast majority of it as an outright gift to the institution. Many of the works they acquired at modest prices appreciated so significantly that their collection became worth several million dollars, yet the Vogels never sold a single piece to breakdown the collection. Included were the works of Sol LeWitt, Christo and Jeanne-Claude, Richard Tuttle and Chuck Close.
Herb and Dorothy still live in the same Manhattan apartment today- with 19 turtles, lots of fish, one cat -once completely emptied, now refilled again with piles of artworks.