International Review of Educational Cinematography (Jan-Dec 1931)

— 55 — The problem is less arduous in the case of school cinemas. First of all, the apparatus themselves are in less constant use and suffer less wear and tear. Secondly, they are subject to closer supervision, not being, as we have said above, hampered by business considerations. Thirdly, and lastly, because there are small machines, with continuous movement, which work much better than the big ones, suited to the purposes of smaller halls, and hence adapted to the needs of schools and similar institutions. Two classes of persons are, therefore, concerned with the two first points: official or experts to whom the service of supervision is committed; technicians to study the possibilities of obtaining projection apparatus that minimise the wear and tear of film, especially at the perforated margins, which, by abolishing or reducing intermission, would ensure normal projection from the standpoint of eyesight. The points stressed in the Lewis report — the angle of vision of the spectator, the proper distance of the screen, etc., are also matters coming within the competence of the cinema police and depend on the observance of proper standards of building. This report, however, does not invalidate the basic concept that the cinematograph, as such, does not endanger the eyesight of the audience, or at any rate does so no more than other forms of ocular activity, such as constant and tiring reading (the most frequent cause of short sight), attendance in strongly lighted lecture halls, theatres, etc. Prof. Ovio's observation on the rapidity with which films are turned is obviously important. It should be borne in mind that films are usually " shot " at the speed of from x6 to 18 images per second, while normal projection is made at the average rate of 20 per second. If the speed of the projection could be brought up to 40 images per second, the phenomenon of intermit tence — which is certainly injurious to the sight — would be eliminated, but we should have a yet more hasty stampede on the screen, which, besides being anti-aesthetic and grotesque, would compel the eye to follow the scene yet more closely so as to keep pace with the movement; and this, in its turn, would injure the sight. Under present systems, 40 photograms of film are not turned per second because the movements of the persons would become positively ridiculous; the normal rate of 20 to 24 images being in vogue. A half-way system is sometimes followed, which diminishes the intermittence, without getting rid of it, and which tires the eyes by the speed of the movement. Thus the damage is two-fold, though each of the two concomitant factors may be diminished. Apart from the possibilities of continuous-movement apparatus already referred to, which deserves further study, it would be desirable to investigate whether, by a different system of photographing (by the slow or accelerated processes, for instance) it might not be possible to harmonize the spectator's view of the image with the reproduction on the screen. In any case, this is all matter for purely technical study, which can hardly present insuperable difficulties and might well succeed in correcting one of the worst drawbacks of the cinema. Some of the oculists who have been called upon to cooperate in our studies have called particular attention to the captions, owing to the form of the type used and the brusque passage from the grey tones of the picture to the