From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Page from a publication demonstrating photographic exposure methods for scenes with high contrast.
| Identifier | ExFiles\Box 168a\3\ img526 | |
| Date | 1st May 1950 guessed | |
| Fig. 8 above. Fig. 9 below. Fig. 10. This is not a combination print but is a straightforward photograph of the judging of a lantern slide competition. The room was darkened except for a small auxiliary light used to illuminate the figures. The range measured by the S.E.I. Photometer from the highlight on the screen to the dark foreground shadows was originally over 250 to 1. The reflection range of glazed glossy paper being only 50 to 1, the projector illumination was accordingly reduced to give this ratio. The exposure of 15 seconds at f/8 on HP3 film was then determined by the shadow method as described on pages 7 and 8. Fig. 8. This is typically a scene where the lighter tones must be correctly reproduced but where the shadows and street lamps must be ignored owing to the extreme range. The exposure was not recorded but would be determined by the highlight method based on the gradations in the distant snow-clad mountain (see page 17). Fig. 9. The exposure for this interior might be based on the back of one of the pews, but in view of the obviously long brightness range a check would be made on the brightest part of the near right hand pillar to ensure that the range was not excessive. If this was found to be more than about 100 to 1 the highlight method (page 17) would be used to be sure of retaining the delicate highlight gradations. The photometer could also have been used here from floor level to determine by the normal shadow method the exposures required for photographs of the mural decorations on the ceiling. 25 | ||