Amateur Photographer & Cinematographer (1935)

December 4th, 1935 The AMATEUR PHOTOGRAPHER p 6 CINEMATOGRAPHER a Jetters to the Editor The Editor is not responsible for the opinions of his correspondents . EVEN ILLUMINATION IN ENLARGING. Sir", — If you could kindly spare the space I would be very interested to know whether any other of your readers have experienced difficulty in obtaining even illumination of the bromide paper when using a vertical condenser enlarger with gas illuminant, and whether they have been able to effect a cure. I find that I get a slightly brighter centre at f/4.5. By care¬ ful stopping down to about f/5 I can usually get fairly even illumination, but if, for instance, I wish to correct verticals (admitted this should never be necessary) and stop down, even to f/8, I get a dark centre patch. To stop down further is impossible, the trouble becomes so serious. The lens is of first-class make and, in fact, I have tried two or three others of slightly varying focal length but also of good make, with similar results. If it was not for the brighter centre at f/4.5 I would say that the dark patch was caused by a small “ dead ” centre of the inverted mantle. As I do not wish to employ a ground-glass diffuser, I would be grateful to any reader who can suggest a remedy. Are mantles obtainable without a " dead " centre which I could try ? I have used both cheap and standard price varieties without effecting an improvement. — Yours, etc., W. HECTOGRAPH JELLY AND EASEL. Sir, — Regarding enquiry by C. D. (Ealing) a more practical method of attaching bromide paper to the enlarging easel is that which has been suggested before, viz., attach lengths of insulating or adhesive tape (say 6 xf in.) diagonally across the four corners of the easel. The bromide paper can be gently pressed against these strips and pulled away after exposure. — Yours, etc., T. A. M. MINIATURE AND OTHER MATTERS. Sir, — The letters of several of your correspondents published in a recent issue of "The A.P.’’ are of considerable interest, and with your permission I would like to comment upon them. Mr. A. Nation states that in his opinion the miniature camera is but a passing craze. I think it must be obvious from his letter that he is not speaking from practical experience. Minia¬ ture cameras — miniature so far as size goes — have been with us for many years. Thirty years or so ago I owned a little camera of the shape of a watch. No one, however, would pretend that such small cameras were anything more than " stunts.” They are not to be compared with the precision instruments of to-day. Any one who has handled such a camera, for example, as the Leica, cannot fail to be impressed, not only with the workmanship, which is superb, but with its advance in design and technique. Mr. " S.-S.,” in his letter, complains of the poor results which he has obtained from processing executed by D. & P. firms. It should be obvious that it is impracticable to expect D. & P. firms to make a good job of Leica films. But, fortunately, the remedy is simple — and inexpensive. Let him do his own processing. With a Correx tank he will be assured of technically perfect negatives — provided that his exposure is correct — and each negative can be entirely free from finger¬ marks and pinholes. I am not an expert, and claim to possess only ordinary intelligence. During my summer holidays I exposed 300 Leica negatives, and on my return, I developed them in a Correx tank, carefully following the maker’s instruc¬ tions. As a result, I have a collection of negatives which, without exception, are absolutely free from any imperfections. If a man is not disposed to go to this trouble he should not buy a miniature camera. Such cameras emphatically are not intended for those who will not take the trouble to learn how to use them. Mr. J. Atkinson complains of the price of developing tanks, and compares them with bakelite articles that can be bought for a few pence in a sixpenny bazaar. Surely this is entirely beside the point. A well-designed developing tank is also a precision-made instrument. Referring to the Correx tank — I am entirely unconnected with the makers — the tools for this moulding must have been very costly. One might reason¬ ably assume that the preliminary research-and experimental work cost a great deal of money. In any case, surely the labourer is worthy of his hire. If Mr. Atkinson is able to develop films satisfactorily in a jampot all credit to him, but I prefer to make sure of getting satisfactory results. Previous correspondents have referred to the high prices charged for these foreign precision-made miniature cameras. It is, of course, regrettable that there is no British equivalent. But let us be broadminded and admit that there are no British equivalents either because (a) we have not the experienced workpeople available to make them, or (b) that British camera manufacturers have insufficient confidence in the market. So far as I can see there can be no other reason. — Yours, etc., ERNEST R. GILBERT. LANTERN SLIDES BY THE CARBON PROCESS. Sir, — Where large scale projection is contemplated an improvement in working may be effected by squeegeeing the tissue immediately after sensitising on to a ferrotype plate. When dry it will come away with a very smooth, glossy surface which will make perfect contact with the negative. — Yours, etc., P. E. ABRAHAM. A MINIATURE NEGATIVE TIP. Sir, — I would like, through your valuable paper, to make the following suggestion to “ miniature ” workers. As soon as the film has been developed and dried, cut it up into strips of three exposures, and print on self-toning paper, six in a quarter-plate frame. It is not necessary to be particular about this, as they are not for show. I find these very useful when enlarging ; besides, any remarks as to exposure, title of subject, etc., can be written on the back, thus being useful for future reference. Hoping this will be of interest. — Yours, etc., J. ARDEN. LENS DISCOLORATION. Sir, — In the October 30th, or thereabouts, issue of The Amateur Photographer I notice a Reader’s Question from A. J. (Eltham) regarding lens discoloration. He states that the front element of his lens shows a purplish colour, and that this discoloration cuts down the effective working aperture of the lens from f/4.5 to about f/8. From this description I would say that A. J. has a lens with a front element made up of two or more pieces of glass which are cemented together and that the cement between these units has gone bad for one of several reasons. The cure is to send the lens to a repair shop or to the manufacturers, and have the elements re-cemented. If the camera is a small hand outfit the cost should not be over a couple of dollars (American prices may be higher, but that is about what it would cost over here). This deterioration of the cement is no indication that the lens is of inferior make or quality, but is usually the result of carelessness on the part of the owner. Usually it is the result of leaving the camera where the lens is exposed to the direct rays of the sun. A friend of mine who is a commercial photo¬ grapher and carries cameras in a trunk on the back of his car has had several lenses go bad in the last few years from the vibration of the car. This chap, however, drives 30,000 to 40,000 miles per year, so the average amateur need not worry about this. I have carried a Graflex in my own car for prob¬ ably 50,000 miles over all kinds of American roads, and so far my lens is perfectly all right. — Yours, etc., C. F. ROSS (Philadelphia). [ A large number of letters to the Editor have been held over owing to lack of space. — Ed.] 545 23