They recognized clearly that the new scheme could not become really profitable on a large scale as long as only one person at a time could see the pictures. Both the well-known French manufacturers of photographic supplies and the English engineer considered the next step necessary to be the projection of the films upon a large screen. Yet this involved another fundamental change. In the kinetoscope the films passed by continuously. The time of the exposure through the opening in the revolving shutter had to be extremely short in order to give distinct pictures. The slightest lengthening would make the movement of the film itself visible and produce a blurring effect. This time was sufficient for the seeing of the picture; it could not be sufficient for the greatly enlarged view on the wall. Too little light passed through to give a distinct image.