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).
Manual page explaining photography techniques for industrial and controlled lighting using an S.E.I. photometer.
| Identifier | ExFiles\Box 168a\3\ img528 | |
| Date | 1st May 1950 guessed | |
| 28 29 Fig. 14 (above). Industrial interiors, with or without auxiliary lighting, are all well within the scope of the S.E.I. Photometer. The existing artificial lighting was used here, the exposure being 20 secs. at f/11 on HP3 film. The shadow method was used, the 'spot' being matched on the shadowed area on the left. No reading could be obtained from an ordinary photo-electric meter. (See normal working instructions on page 7). Fig. 13. This illustrates the application of the keystone technique described on pages 17 and 18. For such 'controlled lighting' subjects the white film speed index mark is set to the B.S. logarithmic exposure index + 5° keystone correction for a normal face tone. The photometer spot is matched on the brightest part of the face, which results in a consistent negative face tone density at a controlled level. An identical exposure would have been indicated in this case by matching on the cigarette but using a keystone correction of +1° instead of +5°. | ||