Amateur Photographer & Cinematographer (1933)

Im AMATEUR PHOTOGRAPHER ] o 6 CINEMATOGRAPHER o I December 13th, 1933 Rl eaders Questions ANSWERED General. — All communications for the Editor should be addressed : “ The Editor, The Amateur Photographer and Cinematographer, Dorset House, Stamford Street, London, S.E.i ” and in every case, without exception, must give the name and address of the writer. Contributions. — The Editor is glad to consider original, up-to-date manuscripts on photographic subjects. All contributions must be typewritten, or in very legible handwriting on one side of the paper only. Letters or communications arising out of matters already appearing in the paper are not paid for. The Editor disclaims legal responsibility for the safety of matter submitted to him, but he will endeavour to return rejected manuscripts, -tc,., when a stamped addressed envelope is enclosed. MSS. or prints that are not actually accompanied by a stamped wrapper or envelope can in no case be returned. Reproduction fees for prints are only paid by arrange¬ ment beforehand. The sending of a print, without any condition stated, will be taken as permission to reproduce it without fee. Enquiries and Criticism. — Advice, Criticism and Information are freely given, but the following conditions should be read carefully before applying, as any communication which does not comply with the rules must be ignored. (1) See “ General ” above. (2) Every question and every print for criticism must be sent separately through the post, and must be accompanied bv a separate stamped addressed envelope. No exception can be made in any case to this rule, except so far as enquiries or prints from Overseas are concerned, (3) Neither enquiries nor prints for criticism must be enclosed with competition prints. (4.) On the back of each print sent for criticism, in addition to the name and address of the sender, must be the title (if any), and the criticism coupon from the current issue. (5) Enquiries should be clearly written, on one side of the paper only, and should be specific and not general. Such enquiries as ' How can I take interiors ? ” or " Can you give me some hints on outdoor portraiture ? ’’ are too veneral to be dealt with in this sectioD. (6) All envelopes should be distinctly marked “ Query *’ or “ Criticism," as the case may be. (7) Prints are sent for advice or criticism on the distinct understanding that by so doing per¬ mission is given for their reproduction without fee. We endeavour to deal promptly with enquiries, but cannot undcrta ,e to answer by return cf post, nor can we give precedence to any enquiry. A selection of those replies is printed each week, but all questions are answered by post. Enquiries from abroad must contain a coupon also, but it need not be from the current number, and should be cut irom the latest issue to reach the enquirer. Copying a Print. I have a sepia-toned enlargement on rather rough paper, and have broken the negative from which it was made. Is it possible to copy such a print ? M. G. (Coventry.) The print can certainly be copied, the chief difficulty being to avoid a grainy image due to the rough surface. We should advise you to soak the paper and then give it a few minutes in a mixture of glycerine and water, say one in ten. Squeegee the print on to a sheet of glass, and copy on a slow ordinary or ortho plate. The print can then be stripped from the glass, washed and dried. Safelights. Will you indicate the colours of the safelights suitable for use with different kinds of plates and papers ? R. D. (Croydon.) The colours can only be roughly suggested. Well-known makes of $afelights are numbered, and their use indicated, so that a suitable number in the series can be selected. Here is a rough suggestion : chloro-bromide and gaslight, yellow ; bromide, orange ; slow plates and films, orange-red ; ortho plates and fast ordinary, ruby red ; panchromatic, green. Development Time. Is it a fact that pack films require 25 per cent more development than roll films or plates ? H. H. (Bath.) It is not at all safe to lay down a general rule which would suggest that all film packs require 25 per cent longer development than all plates or roll films. This is far from being the case. What you want is a list, such as that given by Watkins, indicating roughly the class into which various emulsions must be put so as to give them an appropriate development time. You would then find that some pack films require less development time than some plates. Stops in Enlarger. I have an old enlarger, the lens of which has stops down to f/32. 1 notice that some modem enlargers have only one fixed stop to the lens. Are stops any advantage in this case ? T. G. P. (Ipswich.) If an enlarger has a direct condenser light it is quite possible that the point of the cone of rays may enter the lens so exactly that moderate stoppingdown will not affect the light. With daylight or diffused artificial light the stops operate in the usual way. There is another point which arises. Modern anastigmats will give good definition over the whole of the picture plane at their full aperture, but older lenses with a curved field have to be stopped down to give good definition. Fine-grain Developer. Will you give me a formula for a developer that will give a fine-grain negative suitable for enlarg¬ ing ? W. A. C. L. (Aldershot.) We have on several occasions given what is known as a fine-grain developer, but apparently you have overlooked it. You must remember that grain depends on other factors besides the developer used, such as the character of the emul¬ sion and proper exposure and develppment. A formula is as follows : Metol . . . . . . 18 grs. Sodium sulphite (crys.) . . 4 oz. Hydroquinone . . . . 45 grs. Borax . . . . . . 18 grs. Water to . . . . . . 20 oz. Sulphide Toning. I have been told that with sulphide toning of bromide prints it is almost impossible to get two of the same colour. Is this a fact ? E. C. H. (Farnborough.) Provided that the prints are on the. same brand of paper, and full)' developed with the same kind of developer, there is no reason why the colour resulting from sulphide toning should not be exactlv uniform. Silhouettes. What special apparatus is required to make silhouette photographs like that enclosed ? F. D. W. (Salisbury.) Silhouettes of the kind to which you refer can be made without special apparatus at all. Briefly, the method is to stretch a sheet of paper or thin white fabric over a doorway between two rooms. The sitter is placed close to the sheet and focussed upon sharply. The lights in the room are then extin¬ guished, and the sheet is brightly illu¬ minated from the other side by means of flashlight, magnesium ribbon, or something of the sort. This is so managed that the background has sufficient exposure, but few or no details are visible in. the subject itself. Dirty Negative. Can you tell me the reason for the smeary appear¬ ance of the enclosed negative, and the method for removal ? L. C. W. (Worcester Park.) The glass side of your negative is simply dirty. If you breathe on it and rub with a soft rag the marks will at once disappear. It is advisable to clean the glass side before putting the negative to dry. Metal for Tanks, etc. What metals can I use that will be unaffected by developing and fixing solutions ? S. It. (Romford.) We do not know if there is any metal that is entirely unaffected by either acid or alkaline solutions. Nickel is most commonly used, but monel metal is rather better. No metal should be ex¬ posed to the action of solutions longer than is necessary, and all metal apparatus should be thoroughly washed after use. Duplicating Negative. I want to duplicate a valuable negative. I have tried doing this with warm-tone lantern plates. Is there any other lantern plate more suitable ? G. S. (Southport.) We should certainly not advise you to use a warm-toned lantern plate for duplicating a negative. You will do much better with a slow ordinary plate, both for the positive and the negative. The following is the Solution to the Crossword Puzzle printed in the Christmas Number of “ The Amateur Photographer” last week. 24 552