Amateur Cine World (November 1936)

LETTERS TO THE EDITOR Approval for the Smethurst Wtehl ght Sir,—In your September issue Mr. G. Sewell takes exception to the highlight exposure method as expounded by Mr. Smethurst, partly on the grounds that when a subject has a range of contrast that is too reat for the emulsion in use, the system Fails to give full detail in the shadows when obtaining it in the high lights. The answer to Mr. Sewell’s criticism appears to lie in the following words, which are printed with the exposure table in the instruction booklet for a well-known make of reversal stock :— “It will be noticed that special categories are not given for different types of subjects since the correct exposure remains the same whether the subject is relatively near to or far from the camera and whether or not the subject includes shadows ; this is because exposure should be correct for the highlights. Hence, subjects including both very dense shadows and strong high-lights should be avoided as far as possible.”’ I have tried Mr. Smethurst’s methods with this particular material and have obtained results consistently finer than I had had before when using ordinary methods. Regent Place, 8S. R. K. Browne. Rugby. ECHO OF A PAST WAR. Sir,—The correspondence in __ your September i issue between Mr. G. H. Sewell and Mr. P. C. Smethurst must be of particular interest to “‘ still’’ photographers who are old enough to remember the _ oft-times ferocious correspondence which adorned the columns of pre-war photographic journals on the question “ Should exposure be based on the light shining upon the subject or alternatively on the light reflected from it ?”’ believe I am right in saying that this thorny question was never settled definitely one way or the other. It will, I think, be admitted that Alfred Watkins, the inventor of the Watkins Meter and the originator of Factorial Development, is fully entitled to be regarded as an expert on the subject of light values concerned in photographic exposure. I therefore think the following passage extracted from “ The Watkins Manual ”’ is worthy of consideration in connection with the present controversy. The passage is as follows :— Reflected Light “Another objection to the use of an actinometer, repeated to thousands of readers of the Ilford Manual, is that to be perfect it ought to test the light reflected from the subject and not that falling upon it. This theory is quite a false one. I have tested it in this way :—Two plaster casts were taken, one white, the other a dark brown. The light reflected from each was carefully tested by an actinometer under equal circumstances, all extraneous light being carefully screened off. Plates were then exposed for times proportionate to the actinometer times. As I expected, the two negatives were identical in density and would, if printed, give false ideas of the difference between the white and brown casts.” System This appears almost a direct answer to Mr. Sewell’s paragraph starting ‘‘ There is yet another weakness of the high light system . "' According to Watkins the same exposure should be given to both. The truth, I suppose, is that our idea of correct exposure is largely governed by our individual taste so far as regards the scale of contrast we prefer in our pictures. Some deliberately under expose all their shots because they like to see rich, velvety blacks on the screen, although there may have been them without the use of graduated filters, the plain 1$ times yellow giving splendid rendering. The system is easy to use and if a trial 50 ft. test is made before beginning serious shooting one can decide exactly what density of image meets one’s requirements and then carry on knowing that that image will be consistently reproduced—-surely a great ad vantage. Sheffield, ro. K. G. Tortretp. THE SKY AS HIGHLIGHT From Mr. P. €. Smethurst Sir.—I notice in the October issue of The West Essex Film Society went to the South Kensington Museum for this exterior for ‘* The Student,’” their current is being congratulated by his frien no actual black or very dark shades in the original. Most of us prefer bright and sparkling pictures to flat ones, notwithstanding the fact that the latter may be a more faithful rendering. Some prefer the hard contrasts of the ordinary gas light print, others the softer results of platinum or carbon, and so we mostly expose to produce the results we like, whether they be strictly a record of the actual tone values of the original or not. Nevertheless, I am personally very much interested in Mr. Smethurst’s high light system, which I think is a big step forward in simplifying exposure problems. astL Reynotps (Hon. Sec., South Manchester A.C.S.) ‘**EXCELLENT RESULTS ”’ Sir,—You asked for reports on readers’ results with the Smethurst Highlight Exposure System. I have exposed goo ft. of Agfa Pan and 100 ft. of Kodachrome by this method and results are excellent, far superior to those obtained by the old method and absolutely consistent. Further, clouds are rendered on every shot which includes 368 oduction. The Student, on right, on leaving the exam.-room. Amateur Cine that a letter appears from the Secretary of the Heston C.C. mentioning a high-light exposure test in which the meter was pointed at the sky. This method of estimating exposures may be found very satisfactory in_some circumstances, but the experience of Francis and myself in test work leads us to the conclusion that it can give extremely misleading results on many occasions, primarily because the light from the sky is not the whole light falling on a high-light and the proportion of sky-light to sunlight varies very greatly with the weather conditions. So far as our experience goes, the only way in which really reliable and consistent exposure readings can be got, is that of using a standard reflecting surface for the meter a in the shape of an artificial highight The sky is very liable to lead to inaccurate results and to poor shots on certain particular occasions, but I should be failing in my duty if I did not point out this fact, since it was I originally who suggested the use of the sky as a high-light in Amateur Cine. Bolton. Puitie C. Smetuurst.