Digital BW, The Print

> > I don't know quite what you mean here...we only measure
> relative values, as
> > in 2 times, 3 times, 4 times....1000 times...only integer ratio values.
>
> What he is saying is that the CCD's voltage is analog and therefore
> infinite.

That's a misnomer.  Analog is not infinite.  It is limited by noise, and
that is what dynamic range is...the largest signal over the noise.  If you
have a maximum 6V signal, and your noise level is .003 volts, you have a
dynamic range of 3.3.

> Why can't, using your above example, someone make a scanner using the
> more sensitive 14bit A/D converter on the less sensitive CCD from the
> 10bit scanner. (I assume you mean sensitive as in the ability of the
> CCD to judge brighter or darker tones)  This should allow more tonal
> information over the same Density Range.

Nope.  The values you get out of the CCD/AD are RELATIVE.  2 is twice as
bright as 1, and 4 is twice as bright as 2, no matter what CCD or A/D you
use.

You need to have a more sensitive CCD to give you less noise...hence the
need for more bits to increase the dynamic range so you can read the smaller
signals that are less than 10 bits can represent...which is why you get an
increase in the shadow detail (for chromes).

Keep in mind, the analog output of the CCD, no matter what it's noise, is
matched (voltage wise and/or current wise) to the input range of the A/D
through analog circuitry.  The A/D (as in number of bits) is chosen (as well
as the analog interface circuitry) to match the CCD...one typically doesn't
use 24 bit A/Ds when the noise level is only good for 10 bits of that 24!
Even if you did use a 24 bit A/D, only 10 bits of it would be "useful",
because of the noise.