The Cine Technician (1935-1937)

24 The Journal of the Association of Cine-Technicians August, 1935 In practice, however, the vertical movement being so small in relation to the horizontal speed of the scanningapertures, this effect is found to be negligible. As any aperture moves across thq projected image of the film the amount of light passed through that aperture varies naturally with the density of the film. The photo . cell which is arranged behind the disc, therefore, receives a varying light flux, as each aperture travels across the film. This, of course, in the usual way sets up variations in the electron stream of the cell, these variations being amplified and passed by wire or wireless to the receiving end. This system is, of course, applicable to anv number of lines. With a suitable disc a low definition 36-line picture may be transmitted, or by substituting another disc and driving motor a 240-hne picture may be produced. It is usual, if using 100 lines or over, to arrange for the number of disc apertures to be half the number of lines it is desired to transmit and to revolve the disc twice per picture frame. Thus, instead of using a large disc with, saj' 100 aper•tures, running at 1500 r.p.m., the same effect may be obtained by using a small disc containing 50 apertures and running at 3000 r.p.m. By the time the fiftieth aperture has passed the downward moving film, only half the picture has been covered and the disc has completed one revolution. Number one aperture then scans again and the same fifty repeat over the bottom half of the picture. BAIRD TELEVISION LTD. 17'5 mm. Film Picture and Sound Track for Process. Time 30 sec. overaM. Immediate Film Transmitter By Alan Lawson One of the most practical ways in which fully-extended stage or outdoor shots may be transmitted is the intermediate film process. This, fundamentally, is the same as a standard film transmitter, as far as the television section goes. BAIRD TELEVISION LTD. Transmitting a Spanish Scene from No. 1 Studio. CRYSTAL PALACE. (240 lines definition). Instead, however, of the gate being fed 1)\ film, which has been taken and processed separately, it is fed instead with film which comes continuously from a camera which is actually ])lu)tographing the scene it is desired to televise. Interposed between the camera and the scanning gate are a series of tanks, through which the film passes, undergoing development, fixation and washing. The overall time between the actual moment the film leaves the camera gate to its entrance into the scanning gate varies according to the amount of development time and fixation time required by the type of film stock in use. In Germany it is usual to allow nearly one and a half minutes' delay. In England the standard delav time is just 40 seconds. Sound is recorded in the usual wav and taken off after the film has passed the scanning gate, being timed, of course, to synchronise with the picture. The photographic side of the intermediate film process is, in practice, very similar to normal studio cinematography. Processing. — We use a soft working panchromatic stock, of fairly high speed (about 15% slower than the S.S. panchromatic used in studios). The time occupied in processing of necessity must be reduced to an absolute minimum ; development takes 5 seconds and fixation 10 seconds and the whole process is completed within 30 seconds, this including thorough hardening, washing and scanning. Studio. — In the studio we use about lO"^ more light than that used in film studios. The principles of lighting are the same, only more care has to be taken with the choice and lighting of backgrounds, especially for close-ups — e.g., a blonde needs a fairly light background, etc. Tlie standard of lighting is rather exacting, inasmuch as long shots and close-ups have to be done with the same lighting. This is on account of the scene being taken and transmitted right through without any breaks for moving the camera in for close-ups. Any close-ups that are required are done by changing the lens. A negative of fairly good quality can be got by this method, but only with careful rehearsals and rehearsals on actual film. By this I do not intenil t(t implv that one can get as good close-ups or long shots by this method as by lighting separately for each shot. Exteriors. — There is no departure from normal work on exteriors. We use filters and the same stops as used on .S.S. j)anclu"omatic stock.