Amateur Photographer & Cinematographer (1935)

Ihi AMATEUR PHOTOGRAPHER p 6 CINEMATOGRAPHER a December 25th, 1935 The Best Screen for an Amateur Picture Show SPEAKING only in terras of the orig¬ inal picture size, it may be said that cinematography is at a great disadvantage when compared with lan¬ tern-slide projection. Most workers know that the tiny picture on a 16-mm. frame (the larger of two very popular amateur sizes) can be accommodated many times over on the familiar 3^x3! glass lantern-slide. Hence, when the pictures are projected to fill a full-size screen the smaller image is being called upon to perform far greater feats than the other. Then, too, it is important that cinema¬ tographers do not overlook the regular intervention of the shutter, which — as¬ suming the latter to possess two sectors each with an angle of 90 degrees — must always result in a sacrifice of half the available illumination. The lantern slide has not to sustain this reduction in light, and the screen brilliance of cinemato¬ graph pictures would compare very harshly with that of the “ stills,” but for two counter-advantages. The first of these is the highly-efficient optical system possessed by all highgrade cinematographs, and the second is represented by the unusual care with which manufacturers have attended to the matter of screen surfacing. Individual Conttol. The first of these factors is standard with most projectors of repute, and over it the worker has but little control. Such projectors are now avail¬ able for each gauge (and, in one case, for both gauges) of film. But with regard to the second factor — that dealing with the selection or preparation of the screen surface, the enthusiast has much greater scope for the exercise of indi¬ vidual control. He can, for example, knowing the limitations of his lighting equipment, keep down the dimensions of the screen to such an extent that he will not be troubled by poor illumination. By SIGURD MOIR. In addition to this, he is now able to choose a screen surface that will reflect a great deal more light than the custo¬ mary fabric sheet used in slide projection. And, what is even more important, he can select that surface with adequate regard for the conditions under which projection is usually carried out in his own particular room. Reflection and Viewing. The reason that no common screen can be found to satisfy projection in two totally different apartments is not entirely obvious, although it can be made so as the result of experimenting. All opaque screens, of course, reflect most of the light that falls upon them ; but this light is not always reflected at the same angle. Some screen surfaces — like those represented by whitewashed walls and painted calico sheeting — pos¬ sess a very wide angle of reflection or dispersion, whilst others such as those with “silver” and aluminium surfaces have a narrow angle. The practical importance of these differences lies in the fact that observers viewing the silver screen image from an acute angle (with the screen and not with the optical axis) would probably remark on the paucity of illumination as com¬ pared with results observed under identical conditions with a white screen. Other observers grouped about the axis of projection would be just as emphatic that illumination enjoyed an appreciable improvement when the silver screen was substituted for the white one. Of course, there are other surfaces than those extremes selected for the above comparison. Foremost amongst them is the crystal or beaded screen. Distortion. This surface is deservedly most popu¬ lar, because not only is its brilliance to be remarked over both narrow and fairly wide angles, but there is almost complete freedom from image distortion. Distortion is that name given to the caricatured or perverted pictures often seen when viewing the screen from a very acute angle. It is most often ob¬ served when working with the white screen or distempered wall — a most unfortunate circumstance when we re¬ member that this particular type of surface is not only inexpensive but shows the least falling-off in illumination from dead centre to this present angle, which is now giving rise to contorted pictures. The silver screen, as most serious cinematographers would expect to find it, suffers from distortion to a very limited extent ; but so great is the falling-off in illumination at acute angles of viewing that few workers would be content to watch projection from the points at which this distortion begins to affect the image. Helpful Conclusions. For the guidance of those workers who lack the time in which to conduct the experiments, it may suffice to say that the crystal or beaded screen is certainly the best for all general pur¬ poses. Where, however, the room or apartment set aside for the shows is inclined to narrow dimensions, it will be less costly and hardly less satisfactory to rely upon an aluminium curtain. This can be constructed at very little more than the cost of an ordinary white¬ flatting screen. Having remarked upon the virtues of the silver screen as they must appear to the owner of a narrow-angle “ theatre,” it may be well to draw attention to projection " flare ” — a defect not infre¬ quently encountered by observers seated too closely about the axis of showing. This can be avoided by altering the seating, or remedied by applying a suitable abrasive to the offending surface until it loses just its burnishing but not its inherent surfacing. The R.P.S. Dinner THE annual dinner of the Royal Photographic Society, held at the ■ Cafe Monico on December nth, was a very enjoyable function, thanks to the arrangements of Mr. R. H. Lawton, the master of cerefhonies. In addition to some excellent speeches there was a programme of music and magic, and at the end the company was treated to an exhibition of Dufaycolor and Kodachrome films. ' Mr. J. E. Saunders proposed the health of the Society, coupling it with the name of the President, Mr. Robert Chalmers, whom he chided for being one of those Scotsmen who come down into England and carry everything before them. The Society, he said, had been in existence for eighty-two years, and for exactly half that period had rejoiced in the “ Royal ” prefix and patronage. It had done well in all directions, in spite of a bad start. The most recent departure of the “ Royal ” was to set up a Cinemato¬ graph Section ; his only complaint about that was that they would persist in spelling "Cinematograph” with a “ K ” — very soon they would be calling their President Mr. Robert Kalmers. Mr. Robert Chalmers suitably acknow¬ ledged the toast, remarking that the Society would soon have to move into new quarters, and a higher income, best produced by an accession of new members, was essential. It had now reached the 2,000 mark, but there was no reason why it should not be 4,000 before the next year was out. Dr. D. A. Spencer wittily proposed the health of friends from overseas, and referred to some of the clever people 623 whom America had wrested from us. Photography had the international out¬ look. It had brought together men of different countries, whose researches in this field had earned their sincere respect to a much greater degree than their countries’ armies and navies. In photography and cinematography there was a common interest which was leading to world understanding instead of chaos, and tolerance and appreciation rather than fear. Dr. C. E. K. Mees made a reply in which he referred at some length to conditions in America, not only as related to photography, but to the recovery of American industry in general after a period of depression. Mr. Olaf Bloch, with his customary brightness, proposed " The Guests,” and Mr. S. Rowson, representing the cinematograph industry, responded. 22