Amateur Photographer & Cinematographer (1936)

September gth, 1936 iHi AMATEUR PEDTOGRAPHER a 6 CIMEMATQGRAPHER o Exhibitions and Competitions The fiame aiid address in brackets indicates to whcnn to apply for further particulars. The Afuaieur Photographer Monthly Competitions for Beginners, Intermediate and Advanced Workers. — Entries, September 30. Rules in issue of August 26. The Amateur Photographer Novices’ Competition. Prizes of Roll Films for Novices’ Prints. Closing date, September 30. Rules in this issue. The Amateur Photographer Special Competition, illustrating “ Can the Camera Lie ? " Entries close September 30. Wallace Heaton “ 35-mra. Film Competition.” Cash prizes every week. Open to readers of The Amateur Photographer only. Full particulars in a<lvertisement page in this issue. XVme Salon International de Photographic de Bruxelles. — Open, May^October. (M. Maurice Broquet, Secretaire du Salon, Rue du Sceptre, 77, Brussels.) Salon International de Fotografica de Madrid. (Sehor Secretario de la Sociedad Fotografica de Madrid, Calle del Principe, 16, Madrid.) The Folkestone Camera Club, Competition for the best photographs of Folkestone. — Entries close, September 30. Cash prizes. (Ernst. F. Davidson, Hon. Secretary, Folkestone Camera Club, Town Hall, Folkestone.) Chicago International Salon. — Open; July 23-OctO' her 4. (Alex. J. Krupy, Chicago C.C., 137, North Wabash Avenue, Chicago, III.) XXXIe Salon International D’Arte Photographique de Paris. — Open, October 3-18. (M. E. Cousin, Secretaire de la Soci{5te Franc^aise de Photographique, 51, Rue de Clichy, Paris (pe).) Forty-fifth Toronto Salon of Photography. — Open, August 28-September 12. (W. H. Hammond, Secretary, Toronto Salon of Photography, 2, Gould Street, Toronto, Canada.) Tweede ” Focus ” Fotosalon. — Open, September 12-27. (Focus, Ltd., Fotosalon, Bloemendaal, The Netherlands.) South African International Salon. — Open, October. (Hon. Secretary, Johannesburg P.S., P.O. Box 7024, Johannesburg, South Africa.) Royal Photographic Society Annual Exhibition. — Open, September 12-October 10. (Secretary, R.P.S., 35, Russell Square, London, W.C.) Buffalo C.C. Fourteenth Annual Salon of Photo¬ graphy. — Open, September 6-27. (H. W. Schone wolf, 528, Elmwood Avenue, BuSalo, N.Y., U.S.A.) Morecambe, Heysham and D.P.S. — Open, September 9-16. (James F. Levisohn, B.Sc., 5, Douglas Drive, Heysham, Lancs.) Fotoclub Zagreb, Fourth International Salon of Photography. — Open, October. (Fotoclub Zagreb, Masarykova II, Zagreb, Yugoslavia.) London Salon of Photography. — Open, September i2-October 10. (Hon. Secretary, London Salon of Photography, 5a, Pall Mall East, London, S.W.i.) Lincoln Camera Club. — Open, October 15-November 12. (Miss E. Redfern, 146, Burton Road, Lincoln.) XII Salon International de Fotografica, Zaragoza, Spain. — Entries before September 10 ; open, October. (Secretary, Sociedad Fotografica de Zaragoza, Plaza de Sas, 7, Zaragoza, Spain.) Third Canadian International Salon of Photographic Art. — Entries, September 10 ; open, October 23November 15. (Exhibition Secretary, Canadian In¬ ternational Salon of Photographic Art, National Gallery of Canada, Ottawa, Canada.) Windlesham C.C. — Entries, September 10 ; open, September 25-26. Classes for members (Beginners, Advanced, Professional, also Open Class). (J. C. Hayward, Hallgrove, 'Bagshot, Surrey.) IV International Hungarian Exhibition. — Entries, September 15 ; open, October 24-November 9. (Secre¬ tary, Magyar Amatbrf6nyk^pez6k, Orsz. Szovets^ge, Budapest VII, Erzsebet-kbrut, 9, Hungary.) Rotherham P.S. Forty-seventh Annual Inter¬ national Exhibition. — Entries, September 21 ; open, October 14-17. (E. George Alderman, Ruardean, Newton Street, Rotherham.) Service Co. (London), Ltd., Happy Camp Snaps Competition. Cash prizes. — Entries, September 30. (Service Co. (London), Ltd., 273, High Holborn, London, W.C.i.) Coronet Midget Camera Competition. Cash prizes. — Entries, September 30. (Coronet Camera Co., 310, Summer Lane, Birmingham, 19.) Eighth International Photographic Salon of Japan. — Entries close in Tokyo, September 30 ; open, November (Tokyo and Osaka). (Sec., International Photographic Salon, Tokyo, Asahi. Shimbun, Tokyo, Japan.) Photographic Society of America 100 Print Salon. — Entries, October i. Limit 4 prints. Entry fee $1.00. (Dever Timmons, Salon Secretary, Box 216, Cashocton, Ohio.) The Third Yorkshire Salon, 1936, at Mortimer Gallery, City Hall, Hull. — Entries, October i ; open, October 31-November 30. (Graham Fletcher, Netherlea, Kirk Ella, East Yorks.) G.E.C. (Coventry) Third Annual Exhibition. Open classes for members of Midland Federation Clubs. — Entries, October 14 ; open, November 9-14. (P. H. Crosby, Hon. Sec., G.E.C. Photographic Society, General Electric Co., Ltd., Coventry.) Johnson’s ” Holiday ” Competition. Cash prizes. — Closing date, October 31. (Johnson & Sons, Ltd., Hendon, N.W.4.) U.P. International Exhibition of Photography, 1936. (Lucknow). — Entries, November i ; open, December 5, 1936-February 4, 1937. (Dr. K, N. Mathur, D.Sc., Hon. Sec., U.P. Amateur Photographic Association, Lucknow University, Lucknow.) Entry forms obtainable also from the Editor of The Amateur Photographer. Tenth International Christmas Salon of Pictorial Photography (Antwerp). — Entries, November 15 open, December 20, 1936-January 3, 1937. (J. Van Dyck, Sec., Fotographische Kring “ Iris,” Ballaestr, 69, Antwerp.) Leicester and Leicestershire P.S. International Ex¬ hibition of Pictorial Photography. — Open, February 22-March 14, 1937. (H. Foscutt, 19, Doncaster Road, Leicester.) FACTS and FORMULA ONE or more items of practical value to the amateur photographer are given under this heading in every issue. They are printed in either the vertical or horizontal form as shown here, and each is complete in itself. These facts and formul® are intended to be cut out and pasted on the thin cards of the standard size, 5x3, supplied for card index cabinets. The collection when completed will form a concise guide to photographic practice that every regular worker will value for reference, and for that reason no copies sho^d be missed. ” A.P.” filing cabinets have been specially prepared for this card index, and are now ready. The size of the box is 5^ x 3^ x 3 and each is supplied complete with a set of alphabetical index cards and 150 cards for pasting on the ” Facts and Formulae.” They are obtainable from our publishers, Messrs. Ilifife & Sons Ltd., Dorset House, Stamford Street, London, S.E.i. Price 2s. 6d., post free. 31. DRY MOUNTING A VERY popular method of mounting ^ photographs, as it permits prints to be mounted perfectly flat on any kind of support, permanently and \vithout marking the print. Briefly, the method consists of the use of thin sheets of tissue paper as the adhesive, which have been saturated with a solution of shellac and dried. A sheet of this tissue is applied to the back of the print by touching it here and there with a hot iron or the back of a metal spoon, heated to about 160 to 170® Fahr. This melts the shellac where touched, and makes it adhere to the print. The print and adherent tissue are then trimmed together to the required size and laid down in the correct position, previously selected, on the mount. The print and mount are then placed under pressure between thin metal plates in a dry-mounting press, in which metal pressure slabs are heated to about 170® Fahr. for approximately 15 seconds. The heat and pressure cause the shellac to melt, and the print becomes firmly cemented to the mount. Several small appliances are on the market for dry mount¬ ing for amateurs, but the large machines stUl give the best results. The use of the ordinary flat-iron, suitably heated, has been suggested for dry mounting prints, but, although it can be used, it is not an entirely satisfactory substitute. Dry mounting tissue is best bought already prepared, but may be made by saturating suitable tissue paper in a solution of the resinous gum known as sandarac or gum juniper. It is usually sold in small tears averaging about a quarter of an inch (6 or 7 mm.) in diameter, these tears being nearly colourless. The price is about the same as that of shellac. One part by weight of the sandarac, dissolved in from one and a half to two parts by weight of industrial alcohol, will give a suitable solution for saturating the tissue paper. The prepared sheets are hung to dry flat before use. TO FIND FOCAL LENGTH OF LENS ' I 'HE focal length of a lens is the distance between the node of emergence of the lens and the centre of its focal plane when the lens is focussed on infinity. There are many different methods of calculating the focal length of a lens. For exact measurements an optical bench is necessary, but for most amateurs’ purposes there are a few methods which need but little apparatus and will give results accurate to i/32nd in. One popular method is described below and is suitable for use where the entire lens is moved to and fro for focussing and where the camera has a double extension and a focussing ground glass. First, focus the lens on infinity, on, say, a church spire some little distance away, and mark the position on the baseboard where the focussing pointer rests. Next take a piece of white card about 3x2 in., and cut it into two’ (3 X r in.). Pin one of these pieces on a wall, rack out the lens panel of the camera to give double extension and focus the lens on it to give an image of exactly the same size. The second piece of card serves as a convenient check for the image. Mark again the position of the focussing pointer on the baseboard extension, and the distance between these two baseboard marks is the focal length of the lens. This method is based on the optical law that the focal length of a lens is doubled to obtain an image the same size of the object in focus. 266 29