Amateur Photographer & Cinematographer (1935)

October 2nd, 1935 The AMATEUR PHOTOGRAPHER p 6 CINEMATOGRAPHER o four strips enclose a rectangle a trifle smaller each way than the actual picture-space on the negative. A little of one or other of the short sides of the negative must necessarily be wasted ; and whichever one it may be is slipped under the free edge of the wide strip, and the negative is adjusted so that when held up to the light the clear edges are completely masked all round. The only light that can reach the lantern plate is what passes through the actual negative image. This gives the sort of result shown in Fig. 2. There is no fogging, and masking is facilitated. It may be asked why we should not slip the negative under a cut-out mask on one side of the glass, as in making prints. This is all right for prints, but the definition would suffer on a lantern plate which may be projected on a very large scale. With the device mentioned, the plate just misses the edge of the strip holding the negative, so that nothing whatever is interposed between plate and film. Exposure may be made to the same light as is used for printing gaslight or bromide papers, but the distance may have to be increased to avoid having exposure times in¬ conveniently short. Whatever the distance may be it should be adhered to exactly. I would advise the beginner to start with a brand of plates for " black tone ” slides, and to aim at a clean, pure black image. He can pass on to warm tones later. I would also advise him to begin with Rytol tabloids as a developer. The solution will give beautiful blacks and greys, and has no tendency to fogging. It will give warm tones as well, with suitable plates and modification. If, later on, the beginner finds a better all-round developer for lantern slides he should adopt it. According to the instructions a pair of tabloids is dropped into i\ oz. of water, crushed, and stirred up till dissolved. I prefer to take 5 oz. of water, and with this amount I have just developed a dozen black-tone slides. Development is slower, but it is quite fast enough for me. Of course the exposure for any given negative must be judged pretty accurately, and then the only thing is to know how long to continue development. Shadows appear first, followed steadily by lighter and lighter tones. After a time, as the surface of the plate is examined by red light, it will be seen that the only parts of the emulsion remaining white are the unexposed margins, and the highest lights of the subject. A little later these high-lights become grey compared with the margins. Then stop. Rinse the plate, and fix in acid hypo. When the plate is thoroughly fixed, examine it against a good light, with a piece of ground glass interposed. The slight veil of the high-lights has vanished. If the shadows are too dense, and lacking in transparency, try again with a rather longer exposure. If the slide is flat and weak, and not of a good colour, try again with a shorter exposure. If your second slide is not perfect in every way, make a third. You cannot help getting the right result, and then you can go ahead till you get a good slide practically every time. W. L. F. W. DEVELOPING MINIATURE FILMS MERLYhf SEVERN THE general adoption of the "daylight” tanks for developing " miniature ” films has greatly simplified the process for the amateur, for in most patterns the film can be developed, rinsed, fixed and washed in the security of its apron, avoiding the risks of mechanical injury inseparable from hand development. But even tank development, simple as it is, requires certain precautions. A difficulty confronts the user of a 35-mm. camera in the length of the apron (nearly six feet) necessary to cover his film. Only a contortionist could fix the beginning of the film to the reel without allowing A rubber band keeps the end of the long celluloid apron pom touching the floor. the end of the apron to trail on the floor. Some stand upon a chair, an uncomfortable and even hazardous pro¬ ceeding in pitch darkness. It is simpler, before beginning to load, to roll up about half the apron and slip an elastic band round it as shown in the illustration. When this point is reached in loading the film, the band is slipped off, and the apron now swings clear of the floor. The next point to make sure of is that the developer shall act evenly on all parts of the film ; there must be no blank spots due to airbells or dust, and no streaks due to uneven development. The film should always receive a preliminary soaking for about three minutes, and a small quantity (say one drop per ounce) of Turkey Red Oil added to this water will remove dust and airbells and ensure that the developer flows evenly when it is poured in. There is no need to stress the necessity for using a finegrain developer, keeping all solutions at the same tempera¬ ture, agitating the tank during development, and rinsing thoroughly between development and fixing. For 90 per cent of the average amateur’s work a fine-grain film such as Panatomic or Selo fine-grain panchromatic will prove amply fast; and, besides a far finer grain, will give better gradation and a truer rendering of colour-values. A developer which will give very satisfactory results with these films is the “ buffered borax ” formula, recently given in the Correspondence columns of “ The A.P.” by “ Medicus.” The coarser-grained super-speed films should be developed with paraphenylene-diamine, which can now be bought in a non -poisonous non-staining preparation. When the final washing is complete the film must be hung up to dry, and the surface water wiped off. For this job I have found nothing better than an Agfa cellulose sponge (obtainable at Boots). The sponge is slit down the middle with a knife, while dry, for about three-quarters of its length. It is then thoroughly soaked in water and squeezed out ; the film is held with gentle pressure in the slit, and the sponge is slowly drawn down its length. 337 23