Passage: Filming wrapped after 100 days on April 20, 1985, and the film was delayed from May to August. But after a highly positive test screening ("I'd never seen a preview like that," said Frank Marshall, "the audience went up to the ceiling"), Sheinberg chose to move the release date to July 3. To make sure the film met this new date, two editors, Arthur Schmidt and Harry Keramidas, were assigned to the picture, while many sound editors worked 24-hour shifts on the film. Eight minutes were cut, including Marty watching his mom cheat during an exam, George getting stuck in a telephone booth before rescuing Lorraine, as well as much of Marty pretending to be Darth Vader. Zemeckis almost cut out the "Johnny B. Goode" sequence as he felt it did not advance the story, but the preview audience loved it, so it was kept. Industrial Light & Magic created the film's 32 effects shots, which did not satisfy Zemeckis and Gale until a week before the film's completion date. The compositing involved for the film's time travel sequences, as well as for the lightning effects in the climactic clock tower scene, was handled by animation supervisor Wes Takahashi, who would also work on the subsequent two Back to the Future films with the rest of the ILM crew.

Question: for how long was the film waited for?
from May to August