Amateur Photographer & Cinematographer (1937)

January 13th, 1937 The AMATEUR PHOTOGRAPHER p 6 CINEMATOGRAPHER a Cutting the Film in a Leica By J. R US KIN TURNER. Fig. 1. ALL users of the Leica may not be aware that there is available from Messrs. Leitz a small knife to cut the film in the cam¬ era if it is de¬ sired to develop part of a spool instead Of wait Fig. 2. ing until all the exposures have been com¬ pleted. The procedure is as follows : Make three ex¬ posures with the lens cap on, in order to wind the film clear, then set the catch shown in Fig. 1 from A to R, which will minimise any chance of scratching by pulling on the film at a later stage. After this, the camera must be taken into the dark-room and the rest be done by touch. The camera lid is next removed as shown in Fig. 2, and the knife is inserted near the windingspool. It may take a few seconds to feel the top edge of the film, but when it is found the knife, which has a Vshaped cutting edge, is pushed down, making a clean cut through the film. Once the film is cut, the rewinding knob is given one turn, as shown in Fig. 3, which serves to free the perfora¬ tions from the sprockets, but does not turn the film far enough to lose the cut end within the film chamber. The winding-spool can now be removed to develop the exposed portion, and the film chamber can be slipped out. Enough film can be drawn out to allow for the usual trimming, which is best done with a sharp knife against the trimming template. Alternatively, a false trailer, ready trimmed, can be attached with a piece of sticking plaster. The latter method saves the film as far as possible, but care must be taken to keep the perforations in alignment or they will foul on the sprockets. In order to keep check on the expo¬ sures, the number on the counting disc should be noted immediately after making the three blank exposures which bring the last exposure clear of the place where the film is cut. Most of the unexposed film has been wound back into the film chamber at that stage, and only a few perforations need be fogged when the white light is used in attaching the trailer. If the trailer added to the projecting portion of the unexposed film shows about twenty-four perforations (equi¬ valent to three exposures), and a further four exposures are made when it has been loaded into the camera, it will only mean the actual loss of about three pic¬ tures from the total number available on the film before cut¬ ting. For this reason, the three exposures recorded when wind¬ ing on the blank ex¬ posures will account for the loss, but as we are going to make four, instead of three, to re¬ set our film, the counting disc should be set after three expo¬ sures to one number less than noted, so that when we wind the shutter for the fourth time in readiness for the next actual exposure, the disc will be correct. The take-up spool on a Leica is not of the same pattern as that on which the film is supplied, or the spool from a B-type metal chamber. For this reason, if it is not desired to develop the cut-off portion at once, it should be wound on to a spare spool, or placed in a light-tight tin until it is required, so as to free the take-up spool for reloading. A Negative-Filing By S. R. PITMAN. Hint MANY photographers, especially miniaturists, find it convenient to file their negatives in strips of three or more, for convenience in handling. Unfortunately, even with the almost automatic modern apparatus, there is often a small number of nega¬ tives which are useless because of wrong exposure or camera movement, or because the negative, although techni¬ cally excellent, does not show the effect aimed at. Distinguishing the Failures. Where negatives are filed in strips, it becomes desirable to distinguish these worthless negatives in some way so that they can be recognised at a glance. A simple and most effective way of doing this is to punch a couple of holes in the spoilt negative with an ordinary office punch as used for fifing papers. The negative is thus readily distinguished, and when running a strip through the enlarger a " punched ” negative will throw an image of unmistakable appear¬ ance on the baseboard, making certain that no paper will be wasted in pro¬ ducing an enlargement from it. More¬ over, if a print should be made from it inadvertently, as may happen when using a printing-box, the resulting black dots on the print will show immediately that it is from a worthless negative. DRYING AND DRYING-MARKS. 35-mm. film should be carefully wiped front and back to remove all surplus moisture with either a damp wash-leather kept specially for the purpose or a viscose sponge. Moisture standing in drops on the film will show a circular mark when dry that can only be removed by one method. The negative should be com¬ pletely bleached through to the back in the bleacher mentioned below, washed and then fully redeveloped in a non¬ staining developer such as amidol. The best bleacher for this purpose is : — Pot. bromide . . . . 10 grs. Pot. ferricyanide . . . . 10 grs. to each ounce of water. Fig. 5 14 32