[filmscanners] Re: 8 bit versus 16

["" <focus@adnc.com>]

Art-I'm actually partially on your side--I agree that 8 bits is mostly the 
limit of what
humans can discern. There are rare cases of large, "shallow" (not much tonal 
range)
gradients that haven't been dithered, either artificially or by film grain, 
that can show
banding. But again, that's rare. And in any event, there are NO output 
solutions I know of
that actually support 16-bit, so whether or not we can discern 16-bit is pretty 
much a moot
point.

The only time I'm saying 16-bit matters is when you make tonal adjustments, 
either
gamma/levels/curves or dodging and burning. These throw away data. To have 8 
bits of
significant data when you're done you have to start with more than 8 bits.

And if you're adjusting things in the scanner, the scanner's bit depth matters. 
One of the
reasons 1990-and-earlier drumscanners do such a horrid job on color neg is that 
they're
only 8 bits internally, spread over a 4.0 dynamic range. The much smaller range 
of color
neg leaves you only 5-6 bits data--generally an ugly mess.

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