Brett Morgen has been making archival-footage documentaries for 20 years — most notably “The Kid Stays in the Picture” and “Cobain: Montage of Heck.” So when National Geographic head of original programming Tim Pastore called him to say they’d found some “forgotten” footage, as Morgen likes to put it, of scientist and chimpanzee expert Jane Goodall’s first months at the Gombe Stream National Park in Tanzania, it was a good day.

The result was the critically acclaimed feature documentary “Jane,” released in theaters last fall and set to premiere commercial-free on the National Geographic channel March 12.

The film melds 1960s footage with Goodall’s voiceover narration and present-day interviews that feature her. Morgen’s passion for this type of documentary harks back to his days attending Hampshire College in Amherst, Mass. — a school he admittedly picked because Ken Burns is a graduate.

Morgen worked hand in hand with cinematographer Ellen Kuras on camera placement and lighting to optimize and enhance the moment of the interviews. “Often in documentary interviews,” he says, “there’s one lighting setup and one camera position, changing only focal length. With ‘Jane,’ the interviews were constructed so that it would appear to go from morning light into evening light and then into a brand-new day.”

To achieve the effect, Kuras used the Arri Amira camera. “Brett carefully structured his questions for Jane so that we would have a number of opportunities to shift the lighting and the camera positions to capture the change in light during the course of the day,” says Kuras, a longtime animal rights activist. “It was a very astute and creative idea [in order to] subtly influence how the audience experienced the story.”

For the last questions of the interview, and hence for the film, Morgen wanted it to feel like a new day. Kuras says the idea was to achieve a brighter, sunnier and lighter ending. “In effect, [it’s] a new beginning,” she says. “This leaves us with a feeling that defines Jane — bright, clear-eyed and hopeful.”

The original footage — 16mm Kodak color reversal film — constituted about 10% of the 750 hours of material for the doc. The team also sourced the wildlife films shot on Bolex cameras by Hugo van Lawick, Goodall’s husband at the time. Then Morgen, Company 3 colorist Tim Stipan and Kuras logged 250 hours of color-correction work (a process known as grading).

Old 16mm footage can sometimes look stale and off-color, but the “Jane” team succeeded in bringing those images to life. They graded the color, leaning heavily toward blues and greens, then went on to contrast grading, changing the focus on certain elements in the frame and shifting the contrast.

Morgen credits the process for Goodall’s verdict after viewing the documentary: “When Jane saw the finished film, she said it was the first time Gombe had ever been realized on film as it exists in her mind.”