Digital BW, The Print

> I think I'm winding down here on my participation in this thread, so I'm
> taking stock of where we stand at this point. I'm curious after all that's
> been discussed on this topic, what is your position on the usefulness of a
> calculation of dynamic range on an "existing print of unknown origin", at
> least with regard to giving an indication of how many tones THAT print
> contains.

Obviously, it will differ from print to print.  I certainly believe you can
measure it, and the first method that comes to mind is to scan it on a drum
and see what the numbers come out like!

> For a
> print system you'd print a target of known values, measure those values at
> the print, and compare?

Sounds good.  I believe Polaroid are the only ones who have actually
characterized these things via a testing procedure.  I'll ask David if he
happens to have a copy of the testing procedure.

> But in the case of a print of unknown origin, the only way to count the
> tones present would be to do a full "pixel count" along the lines of a
> Photoshop histogram calculation. I can see no way that a few well chosen
> samples will get you there.

I agree...that's a matter of measurement though...but I have certainly, and
I believe most anyone has, been able to say that this print has more/less of
a dynamic range than that print.  Whether that was intentional in the image
or not, isn't relevant, the point is, you can visually see with your own
eyes that two prints have different dynamic ranges.

> Furthermore, tones will either be present or they will not, but
> how many are
> present almost certainly be based upon far more powerful determinants than
> "noise". For instance, the number of tones present in the original file or
> negative - or the printmakers intent!

Right, but again, you are measuring THE print, and only THE print, you don't
care about the origin of the "missing tones".

> But I think it's been shorthanded by the
> printmakers
> to dmax - dmin,

Well, that I don't agree with.  That is clearly density range, and dynamic
range will give you a different "dynamic" than density range will.  I don't
believe it's "shorthand" at all.  I believe density range IS density range,
and dynamic range IS dynamic range.

> And if they can't perceive it
> they don't
> mind?

Right, but as I've said, because your eyes don't perceive it, doesn't mean
it isn't there.

> Now to be fair to you, you never said photographers should make DyR
> measurements, you were just explaining how the dynamic range formula you
> know so well is applied, and making the distinction between it and density
> range.

Correct ;-)

Regards,

Austin