Digital BW, The Print

> Dynamic Range is a characterization how much bigger the maximum
> intensity is
> from the minimum intensity of the system.

> In sound that's the
> ratio of the loudest
> to the quietest.

So, "bigger" == ratio.  I'm good with that.

But to move on to, what I feel, is quite important:

> In an image that's the ratio of the brightest
> to the darkest.

Hum.  Do you mean the darkest to the brightest when talking about density
values?  I'll fly with that ;-)  Let's use two examples, both with DENSITY
range = 2.0:

dMax = 4.0
dMin = 2.0

This gives 4.0 / 2.0 or a ratio is 2.0

dMax = 3.0
dMin = 1.0

This gives 3.0 / 1.0 or a ratio of 3.0

Note the density range is the same for both (and we agree that density range
is dMax - dMin)....but using your "brightest" and "darkest" qualifications,
the dynamic ranges are entirely different...but the difference in intensity
is exactly the same - 100:1 (a density value of 2 is 10**2, or 100, no
matter what the dMax or dMin is).  That's why using "brightest" and
"darkest" doesn't work for dynamic range.

So, the RATIO of the brightest to the darkest, for two examples of the same
density range, do not yield the same dynamic range...how can that be?  Their
RATIOS are the same!

BUT...if we used the equation I have been using, ((dMax - dMin) / noise),
the dynamic ranges WOULD be the exact same, given the same amount of noise
for each.  Hum.

> Austin's ratio is of the high contrast to the lowest contrast.

Yes, that works for me, thanks, I think that is well put.

> It just doesn't jive.

You're right, it doesn't even boogie ;-)

Austin