| 释义 |
pre-exˈposure
[pre- A. 2.]
A preliminary or premature exposure; spec. in Photogr., one given uniformly to a sensitive film or plate in order to increase its sensitivity.
1937G. E. Brown Clerc's Photogr. 582/1 (Index), Hypersensitizing, by pre-exposure. 1953Adv. Electronics V. 77 Table VII shows..the density, D, of the film at optimum pre-exposure. 1967E. Chambers Photolitho-Offset v. 63 When double printing from positives, it is necessary to mask-out each positive in the areas where the other positive is required to print to prevent pre-exposure of the emulsion. 1979Nature 24 May 341/2 Pre-exposure of human red blood cells..to dilutions of Bufo marinus serum followed by washing and resuspension in fresh buffer, caused a dose-dependent inhibition of subsequent 3H-ouabain binding to these cells. 1979SLR Camera June 73/2 The only trouble with pre-exposing the shadows in this way is that they tend to lose density in the print.
So pre-exˈpose v. trans., to expose beforehand or in advance; spec. in Photogr.
1817Bentham Parl. Reform Introd. 326 Brought out, pre-exposed to a damping atmosphere, and thus rendered unfit for use. 1953Adv. Electronics V. 76 In order to achieve high detectivity with photographic materials, it is necessary to pre-expose the negative uniformly in order to overcome the inertia of the material. 1972P. Petzold Effects & Exper. in Photogr. (1973) 70/2 The film should be pre-exposed for only a few shots... Further frames could be pre-exposed at higher or lower levels. |