Steve Underwood wrote:

...

Do you mean the contrast ratio of film or of photographic paper?
Photographic paper, especially colour paper, is quite limited. The
contrast ratio of film can be phenomenal, depending on its type. Slow
black and white film reversal processed into slides can have extreme
contrast, and usually has to be bleached down to the point where it
looks reasonable to our eyes.

When considering the contrast ratio of the eye, remember this is an
instantaneous figure. Our pupils are constantly adapting as we scan
around a scene, and the overall constrast we perceive after flitting our
eyes around a scene can be far higher.

I understood that the accommodation to light levels provided by pupil
size is a rapid but small part of the overall range, and that most of it
is provided by light's bleaching of the photoreceptors. Was I wrong?

Jerry
--
Engineering is the art of making what you want from things you can get.
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