Home Movies (Jan-Dec 1940)

HOME MOVIES FOR OCTOBER PAGE 481 Authored \ by S. J. Williams ed^etciil? 3t denendc epenao upon tli e JjAST month, in the article, “What Type Film Should I Use?” we sought to make clear to the amateur the basic characteristics of all cine films — panchromatic, orthochromatic, and “semiorthochromatic” — and to explain the results to be expected from the use of each. This month, we shall continue with the subject, giving emphasis to the characteristics of the slower, less sensitive emulsioned films. Frequently in advertisements one sees a film referred to as a “semi-orthochromatic” or “semiortho” type. According to statements from the laboratories of one of the nation’s leading film manufacturers, such films are usually of the basically “color-blind” type, though sometimes with a slight degree of sensitivity in the green ; they differ basically from the true “ortho” films, which are sensitive not only to blue and green, but to the yellow, and in some cases (such as Agfa’s Plenachrome) to a limited extent to the orange as well. It may also be pointed out that virtually all of the non-panchromatic films are lacking in shadow speed — that is, granting a correct overall exposure for the picture as a whole, shadows with these films fill up quickly — become so badly under-exposed that they are just empty black spaces— whereas with most of the panchromatic types, granted a correct overall exposure, there will be a reasonable amount of detail visible in most shadows. The illustrations on this page show enlargements made from 16mm frames of each of the respective films. Fig. 1 is a frame from a 16mm “semi-ortho” film and is a good example of the absence of detail in shadows characteristic of this type film. Note that the beach sand records in a normal tone while the flesh of the subjects containing a predominance of red, registers decidedly dark and in some areas, black. Fig. 2 is a frame made on standard orthochromatic film by the same camera, at the same location, under the same light conditions, and of one of the subjects in the first photo. There is a truer rendition of tones throughout the scene, and shadow detail is quite normal in the face of the child. Fig. 3 is a frame from a 16mm panchromatic film, shot at the same beach location, of the same subject, and under the same light conditions. Note the perfect rendition of detail in the shadow cast by a beach umbrella just beyond the child’s head. Such detail could not be obtained with “semiortho” or other color blind films. Also, there is an increased quality of tone in the subject’s features and clothing, not found in either of the two preceding pictures. In the foregoing it may also be noticed that in general the “color-blind” films are the slowest and the panchromatic types fastest. However, speed alone is no evidence that a film is or is not panchromatic. Some of the ortho types — like Agfa Plenachrome and Gevaert Ortho — are quite fast, with speeds of Weston 16 or over, while some of the finer-grained panchromatic types — like Eastman safety film, DuPont “regular” pan negative, Gevaert fine grain panchro and especially Eastman regular 8mm — are relatively slow, with speeds of Weston 12 or even 8. The best test of whether or not a film is panchromatic is to try it and see how it reproduces red and blue. Especially, try it with various filters. If a yellow filter, even with the fullest exposure, doesn’t give an image, the film is color-blind. If an orange or red filter gives just a black, virtually unexposed film, while a yellow filter works, it is an ortho type. If you can use a red filter, the film is sure to be panchromatic. • Illustrated are enlargements made from ( 1 ) a ''semi-ortho " film; (2) orthochromatic film; and (3) panchromatic film. Th ese pictures were especially filmed with the same 16mm camera at the same location and of the same subject to illustrate the recording qualities of the various film emulsions. Interesting is the absence of speed in the shadows and inability to render true tones to red colors by colorblind ''semi-ortho" film, as demonstrated in the first picture. Continued on Page 506 — S ■