Watch LookMovie. Can we take a film back, propose a new version of it in order to update its promises and unfulfilled injunctions? Can we refresh a film, as we say of a computer screen? One can for example say the film, tell its manufacture and its hazards during a conference. Traité d'optique is a film conference that questions the conditions of possibility of a film revival by crossing material culture and utopia, media archaeology and family narrative, about a study film made in 1987. If the conference sometimes replaces the film, can the film itself be a conference?