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).
Photographic comparison of an eagle statuette demonstrating the effect of background brightness on exposure readings.
| Identifier | ExFiles\Box 168a\3\ img523 | |
| Date | 1st May 1950 guessed | |
| Page 14: Figs. 5 and 6. The effect of brightness distribution on indicated exposure readings. The limiting brightness values occur in the bird and since the lighting remained unchanged the exposures should be the same. The area matched by the S.E.I. Photometer was the shadow between the eagle's legs Page 15: The exposures were 2 secs. at f/5.6 on Ilford S.R. pan. plates, the latter and the prints being given identical treatment. A conventional photoelectric meter erroneously indicated 6 secs. for Fig. 5 and ½ sec. for Fig. 6 due to the misleading effect of the background brightness. | ||