Digital BW, The Print

>> No offense Austin, but you really snipped out all my relevant points and
>> didn't answer much concretely.
> 
> Sorry, I answered what I thought was important, and, what I believe, was
> quite clearly!

Fair enough. Perhaps I'm not stating my points clearly enough, or it is I
who missed your point.

BTW, I still think your doing a great job trying to explain yourself to
everyone. Few have your patience and commitment.
 
>> My main point was that for a formula that you suggests indicates
>> the number
>> of tones present in a print, based on sampling as few as three tones,
> 
> No, my formula does not suggest that at all.  It does suggest measuring TWO,
> dMax and dMin, but noise/smallest discernable signal may take many tones to
> measure.

You're right, your formula did not state it, but back when I started this
line of inquiry I quoted the methodology you suggested was sufficient for
calculating the DyR of a print, which was in short: measure your prints
dmax, dmin, and various points from a solid tone between. This will give you
the values needed for your DyR calculation. Then from your DyR you have
another calculation that will tell you how many tones are present in a
print. Remember, you said that DyR is, de facto, the number of tones
present.

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

Do you see where I'm going with this yet?

If you do have linearity of all the tones between your dmin and dmax your
assessment of the number of tones present will be correct. HOWEVER, that
calculation, at least if you take it so far as to assume a tone count from
it, will be way wrong if the print ONLY contains those three tones.

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

>> You also did not speak to my premise that I think that a calculation of
>> tones from DyR is only possible if linearity is assumed, which is not
>> something I would take for granted in a silver print.
> 
> You don't need linearity at all.  Noise can be calculated using calculus,
> and integrated over the entire range of the print...  Knowing math is not
> your strong point?  I am guessing you don't know what integration is, in a
> mathematical sense?  I can explain if you like.

Thanks for the offer. You are perceptive indeed about my math skills <G>,
but I consider my sense of logic to be pretty good, so if you can answer my
point above through logical explanation (or math as a last resort) I'd be
most appreciative. :-)

Thanks Austin!

Todd