The Warsaw Ghetto, where more than 400,000 Jews were sequestered from the Aryan population of the Polish city from 1940 to 1943, was a grand exercise in denial. Life went on to some extent, but there were disturbing daily signs — starvation, intolerable living conditions, disease — that something horrific lay in wait.

In 1942, the Nazis created a shocking documentary, labeled Ghetto, that depicted this cruel purgatory. Ghetto was discovered after the conclusion of World War II in an East German archive and was initially taken as a straight document of life in the Warsaw Ghetto.

Filmmaker Yael Hersonski, who is herself related to a ghetto survivor, revisited this lost film. Later, upon careful examination, it was revealed to be in large part a Nazi invention, a propaganda film designed to further vilify the Jews. In elaborately staged moments, “wealthy” Jewish residents of the ghetto are shown drinking and celebrating in well-furnished apartments, often callously ignoring the suffering of the starved and dying poorer Jews in their midst. In one especially cruel moment, the Nazis force well-fed, neatly dressed Jews to stand next to their ragged, emaciated, dying counterparts in the ghetto, subtly indicting the luckier Jews who, for the moment, have escaped death. The implication is that the more prosperous ghetto residents (who were also shown walking by corpses on the ghetto streets) were immune to suffering. But as history tells us, almost everyone in Ghetto died one way or another, beaten or starved or eventually shipped off to concentration camps. And Hersonski’s A Film Unfinished reveals the reality behind the fiction: the Nazi cameramen on the margins, guiding the action and trying to create scenarios that best served their purpose.

Some things never lose their ability to horrify, and the absolute debasement of other human beings is one of them. Under the pretense of making their propaganda film about the ghetto, the Nazis forced both men and women to undress so that they could capture them in a ritual bath. The expressions of horror and shame on the faces of these people are devastating. In some instances, the Nazis clearly wanted to bend the truth and make ghetto life seem pleasant, even luxurious.

But the actual intent of the Nazis’ film is not always clear. Perhaps it was in some sense a kind of morbid souvenir, the kind a murderer would keep of his crime. At other times plain humiliation seemed central to what they were doing. We are not often confronted with so graphic a vision of impending death. Mostly, it is the documentation of the process of starvation that terrifies; the way both adults and children begin to look prematurely elderly, almost alien with their jutting bones and enormous eyes that convey a deep awareness of their own end. Later footage shows their fate: nearly skeletal, starved-beyond-recognition remains are piled into mass graves by Jewish workers in the ghetto.

In addition to this graphic footage, A Film Unfinished has the transcripts of an interview with Willy Wist, one of the cameramen used by the Nazis to make Ghetto. There are also nine survivors of the ghetto who watch the Nazi film and offer their own memories of life in the Warsaw Ghetto. In some sense, the footage itself is so powerful, that certain devices seem unnecessary. The filmmaker shows the survivors watching the same movie we see. But we hardly need that empathetic filter.

A Film Unfinished is an otherwise necessary deepening of our understanding of the Holocaust and an illustration of the power of film, which can elucidate reality or shroudit in layers of deception and prejudice.