The question of when the Edison lab began working on a filmstrip device is a matter of historical debate. According to Dickson, in the summer of 1889, he began cutting the stiff celluloid sheets supplied by Carbutt into strips for use in such a prototype machine; in August, by his description, he attended a demonstration of George Eastman's new flexible film and was given a roll by an Eastman representative, which was immediately applied to experiments with the prototype. As described by historian Marta Braun, Eastman's product