Amateur Photographer & Cinematographer (1934)

January 3rd, 1934 to AMATEUR PHOTOGRAPHER p 6 CINEMATOGRAPHER a induction period, and then hydroquinone exerts its normal action. What it all comes to, in effect, is what we have known all along, that three or four parts of hydroquinone to one of metol is definitely the best proportion. The function of science once again is to follow up and justify the conclusions of the prac¬ tical experimenter. Colour Snapshots. The one-exposure three-colour camera which Dr. D. A. Spencer showed at the Royal Photographic Society on the occasion of the demonstration evening just before Christmas is a really ingenious production. It owes its existence to a recognition of the fact that there is need for some means of obtaining three-colour negatives with a much shorter exposure than is possible with the automatic repeat¬ ing back, when it is desired to get colour snapshots of small children, flashlights, or topical events in the open air, for all of which the repeat¬ ing back is too cumbersome and slow. The critical arrangement of mirrors and reflectors by which the miracle of one exposure has been wrought, would take too long to describe, if, indeed, it could be described apart from some most complicated diagrams. The first model of the apparatus which was on view had cost, it was stated, something like ninety pounds, and Dr. Spencer said that the cost of an instrument presently to be offered commercially would depend upon the demand, but if any considerable number of people are eager to do three-colour work by single exposure, then the price will be accordingly reduced. A second and less clumsy model is now under construction. Meanwhile, examples of the three negatives thus produced— the subject being running water, which is a pretty fair test of simultaneity — were shown, as also printed colour snapshots which had been taken in November sunlight in r/25th of a second at f/4.5. The A mateur Photographer ” E XPOSURE T ABLE— January EVERY MONTH a brief exposure table will be provided for the assistance of our readers in their practical work. A glance at the current approximate exposures as here given will serve as a reliable guide for most purposes. The subjects will be varied to suit the time of year. The following exposures will serve as a working guide for any fine day during the month, between the hours of 11 in the morning and 1 in the afternoon, with the sun shining, but not necessarily on the subject. Stop used, f/8. The exposure should be doubled if the sun is obscured, or if stop f/11 is used. For f/16 give four times the exposure. For f/5.6 give half. From 9 to 11 a.m. or from 1 to 3 p.m. double these exposures. From 8 to 9 a.m. or from 3 to 4 p.m. treble them. Subject. Ordinary Plate. Medium Plate. Rapid Plate. Extra Rapid Plate. Ultra Rapid Plate. Open seascapes and cloud studies . . 1/15 sec. 1/25 sec. 1/45 sec. 1/60 sec. 1/75 sec. Open landscapes with no very heavyshadows in foreground, shipping studies or seascapes with rocks, beach scenes . . 1/8 y * 1/12 * * 1/25 y * 1/30 > * 1/40 y y Ordinary landscapes and landscapes with snow, open river scenery, figure studies in the open, light buildings, wet street scenes 1/3 y y 1/4 y * 1/10 y * 1/12 y y 1/15 y y Landscapes in fog or mist, or with strong foreground, well-lighted street scenes . . 1/2 * * 1/3 * J 1/6 y * 1/8 y y 1/10 y y Buildings or trees occupying greater portion of picture 1 y y 3/4 y * 1/3 * y 1/4 y y 1/5 y y Portraits or groups taken out of doors, not too much shut in by buildings . . 2 secs. 2 secs. 1 * * 3/4 y y 1/2 y y Portraits in well-lighted room, light sur¬ roundings, big window, white reflector . . 8 y * 6 1 * 4 secs. 3 secs. 2 secs. As a further guide we append a list of some of the best known makes of plates and films on the market. They have been divided into groups, which approximately indicate the speeds referred to above. The hypersensitive panchromatic plates and films require less exposure than the ultra-rapid. Ultra Rapid. Agfa, Special Portrait. „ Super Pan. Film. „ Super-speed Film. ,, Isochrom Film. ,, Ultra Special. Barnet, Press and Super Press. XL Super-speed Ortho. Soft Panchromatic. Studio Fast. Ultra Rapid. Criterion, Enelite. Eastman, Par Speed Cut Film. „ S.S. Cut Film. ,, S.S. Pan. Film. Gevaert, Super Sensiraa. „ Sensima Fast. ,, Sensima Ortho. ,, Super Chromosa. ,, Roll Films and Packs. IIauff, Ultra Rapid. ,, Ulcroma. ,, Ultra Roll Film and Pack. Herzog, Ortho-Isodux Film Pack. Ilford, Golden Iso-Zenith. ,, Iso Zenith. „ Hypersensitive Pan. Plates and Films. ,, Portrait Film (Ortho Fast). ,, Monarch. ,, Press. ,, S.S. Ex. Sens. ,, Zenith Ex. Sens. „ S.G. Pan. Illingworth, Fie t. „ Super Fleet. ,, Super Fleet Ortho. ,, Pan. Fleet. Imperial, S.S.S. Press Ortho. ,, Eclipse. ,, Eclipse Ortho Soft. Eclipse Soft. ,, Eclipse Ortho. ,, Eclipse Pan. Soft. Kodak, Verichrome Film. Marion, Record. „ Iso Record. Selo, Selochrome Roll Film and Film Pack. ,, Selo. Pan. Roll Film. Standard, Film. Wellington, Anti-screen. ,, X Press. Zeiss Ikon, Pernox Roll Film and Packs. Extra Rapid. Agfa, Chromo. „ „ {solar. ,, Extra Rapid. ,, Isolar. ,, Iso Rapid. ,, ,, ,, Chromo. ,, Roll Film. Barnet, S.R. Pan. „ Studio Ortho. Criterion, Iso E.R. ,, Portrait. ,, Roll Film. ,, Special E.R. Ensign, Roll Film. Gevaert, Filtered Ortho. ,, Chromosa. „ S.R. ,, Regular Cut Film. Haupf, Analo-Flavin. ,, Extra Rapid. ,, E.R. Ortho. ,, Roll Film and Pack. Ilford, Auto. Filter. „ S.R. Pan. ,, Pan. Film. ,, Rapid Chromatic. Imperial, Non-filter (new series). ,, Eclipse Pan. B. ,, S.S. Ortho. Kodak, Roll Film and Film Pack. Pathe, Roll Film. Selo, Roll Film. Zeiss Ikon, Roll Film and Film Pack. Rapid. Barnet, S.R. ,, Self-screen Ortho. Criterion, Extra Rapid. Hauff, Ortho Anti-Halo. Ilford, Screened Chromatic. „ S.R. ,, Commercial Ortho Film. Imperial, Non-Filter. „ S.R. ,, S.R. Ortho. Kodak, Cut Film. Lumiere, Extra Rapide. ,, Instantanee. „ Pelliculalre. Medium . Ilford, Empress. ,, Chromatic. Ordinary. Barnet, Ordinary. Criterion, Ordinary. „ Ordinary Iso. Gevaert, Ordinary. Ilford, Ordinary. ,, Rapid Process Pan. Imperial, Ordinary. „ Pan. Process. 8 2