On Mon, 15 Apr 2002 09:45:03 -0230 michael shaffer (michael@shaffer.net)
wrote:
> Slides are usually attributed with an optical
> density of not much more than '3', which limits the number of f/stops to
> ~10. Negatives, on the other hand, are claimed to have the potential for
> ~14 f/stops.
There's no direct relationship between film density range and subject
brightness range, with negs, and tranny only has an approximate correlation
- it still compresses, just nothing like as much. Useful subject range with
tranny is more often nearer 4.5-5 stops max, colour neg and chromagenic B&W
10-12stops. 14 stops? Well, possibly, but according to tests I did a good
few years ago, highlight contrast was so trashed on the far side of 12
stops that I felt it was worthless. Newer materials and scanning rather
than darkroom printing may have improved things, however.
The wonderful thing about colour neg is that usually if you can see the
range you can shoot it, where with tranny very often you have to make an
irrevocable decision about what to throw away.
Regards
Tony Sleep
http://www.halftone.co.uk - Online portfolio & exhibit; + film scanner info
& comparisons
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