Cambodian director Rithy Panh survived the brutal Khmer Rouge regime that took the lives of many of his friends and family. His latest film “Irradiated,” which premiered in competition at the Berlin International Film Festival, does not shy away from human horrors like those he experienced in his youth.

The film pieces together brutal black-and-white archival war footage spread across a tryptic of panels, juxtaposing footage of Hitler with the devastation of Hiroshima and a basket of decapitated heads, or executions and mass burials.

“Irradiated” is a difficult, visceral viewing experience — an artistic choice that Panh pondered seriously, he said in a recent masterclass at the Sarajevo Film Festival moderated by Variety.

“Of course there’s a moral question. Why do you want to show this body? It’s possible to show a body, or not to. It’s a difficult [decision]” in both the selection and editing process, Panh acknowledges. “Why this [image] and not another one? And why at this place and not another place?”

Panh reflected on the work of Claude Lanzmann, who chose not to use gruesome archival footage in his iconic documentary “Shoah,” and Alain Resnais, who did in “Night and Fog,” excerpts of which appear in “Irradiated.” In the end, he decided to make use of such imagery because it helped him delve deeper into his understanding of his own dark past, and the broader question of human evil.

“I watched a lot of images and decided to use only those that had an echo on me, that I came to [having had] the same experience,” he said. ” If an image echoes or resonates in my mind, I assume the responsibility to edit it.”

Watch the full Q&A, moderated by Variety’s Rebecca Davis, above.