Digital BW, The Print

> BTW, I still think your doing a great job trying to explain yourself to
> everyone. Few have your patience and commitment.

Thanks, but you three (Martin, you and Kevin) can really pack a LONG
response, though insightful and interesting...which is what keeps me at
this.  I also appreciate you guys ability to stick with this, and so far, I
believe I've made some headway in the discussion.  If anything, you guys
have helped to clarify/understand some gray (no pun intended) areas that
I've had in this my self.

> From this I took it that three tones where required/sufficient to make an
> assumption of how many tones are present in the print.

It gives you "some" information, yes, but upon further discussion, it became
apparent to me that it is prudent to actually characterize the noise to see
if it is variable over the density range, and if so, what is the equation
that defines the noise.  My belief is it's simply a linear gain adjustment,
but it could also be a ramp of some kind.  I don't really know, which is why
I think it would be really interesting to characterize it.  Martin seems to
know more about this than I do, and I'd like to get his input on this after
he gets his new spectrometer.  (are you listening, Martin ;-)

> I don't have a big point here other than something doesn't compute and I'm
> curious where the break in logic is. I'm going to restate it to
> be sure you
> follow. What you've presented is this: a sampling from three tones is
> sufficient to assess a print's DyR , and from that calculated
> value you can
> calculate the number of tones present. It would seem to me that those
> calculations work well for a system that produces a full and linear
> placement of tones between your dmin and dmax,

You are correct.

> but when those
> conditions are
> not met it would yield an inaccurate tone count. If I'm wrong
> please explain
> why.

You are absolutely right, and I'm happy that you have an understanding of
this to make such an observation!  Bravo!

This is where calculus comes into play.  It is a way of taking into account
the variability of the noise throughout the system.  Here's the deal.  The
noise "change" could be deterministic (possibly linear), which means it's
predictable.  If that is true (and I believe it is), then taking some number
of points (what ever are warranted by the type of equation that defines the
noise over the range, and if the noise is a simple gain, as in it's linear,
two points would do) in the "middle" will give you enough information to
derive the dynamic range.  Let's not talk about what that "result" or
equations would look like yet...

Regards,

Austin