"Newport and the Great Folk Dream", which premieres at the Venice Film Festival on Friday, charts the development of the Newport Folk Festival in Rhode Island in the early 1960s.

Director Robert Gordon picked through 90 hours of black-and-white archive footage shot and then stored for decades by filmmaker Murray Lerner, who made a 1967 documentary "Festival".  

"It was a constant revelation of gems and treasures," Gordon told reporters at a press conference Friday.

Although the documentary sometimes struggles for narrative drive, music fans are likely to soak up gripping performances from American folk legends Dylan, Joan Baez, Pete Seeger, Peter, Paul and Mary, or Doc Watson. 

A young John Lee Hooker sings "Boom Boom", while other Black blues heroes from the era, Skip James, Taj Mahal, Muddy Waters and the electric Howlin' Wolf have the crowd of college-age Americans in raptures. 

Some of the most memorable moments, however, come from the long-forgotten regional acts -- gospel singers or performers of woodcutters' working music, which were a key part of the Newport festival vision. 

But Dylan's fraught relationship with the folk music community provides the main plotline, a story that will be familiar to viewers of the Oscar-nominated "A Complete Unknown" which helped bring Dylan to a new, younger audience. 

"We owe a big thank you to Timothee Chalamet and (director) James Mangold," Gordon said. "Teens, people in their 20s and 30s, who had never had heard of the Newport Folk Festival are now aware of it and interested in Dylan."

"Newport and the Great Folk Dream" ends with Dylan's now-famous performance in 1965 in which he plays an electric instead of acoustic guitar -- upsetting folk music purists -- leading to booing from some in the audience at the end of his set.

Race and war 

In between the musical performances, Gordon also weaves in the era's tumultuous political backdrop, including protests against the Vietnam War, the civil rights movement, and the rise and death of President John F. Kennedy.

The political content is a reminder to contemporary artists of their power and influence, film editor Laura Jean Hocking said.

"One of the things that we wanted to do with this movie was to tell people not to be afraid, to use their voices to speak out against injustice, to speak out against war, against racism, against the erasure of history," she said.

After diving into Dylan's back catalogue for "A Complete Unknown", Mangold told AFP in January it had made him realise how "narcissistic" modern pop music was with its focus on "me, me, me".

The Newport film is one of several documentaries by international directors at the Venice Film Festival, which wraps up on Saturday.

Only one is in the running for the top Golden Lion prize, Italy's Gianfranco Rosi's ode to Naples, "Sotto le Nuvole" (Under the Clouds).

Others include "Ghost Elephants", the latest from German veteran Werner Herzog about a mythical herd of elephants in Angola, and "Cover-Up" about American investigative journalist Seymour Hersh by Oscar-winning filmmaker Laura Poitras and Mark Obenhaus.