Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., Todd Flashner <tflash@e...> wrote:

> 
> Again, no one is asking for a new interpretation of dynamic range, the
> question (in my mind) is, has it been a long held interpretation for "some".
> 
> Jon Cone also uses "dynamic range" as Austin does. Now I know he's not an
> engineer, so he may just be a pedestrian that by chance errs on the "wrong"
> side of the word as Austin <G> (hey, Austin, should we disqualify him
> because he's a pedestrian?), but Austin may not be alone out there:
> 
> <http://www.inkjetmall.com/store/long-dynamic-range.html>
> 
> "Piezography*BW has the longest dynamic range of any digital or traditional
> process. This is a huge claim. However, film has a shorter dynamic range
> than the human eye. Photographic paper has a shorter dynamic range than
> film. The results of both can be plotted as an "S" curve in which the
> highlight and shadows are subject to compression. Piezography*BW when used
> with its internal tonal management system of ICQ profiles renders a perfect
> linerization from dMax to dMin."
> 
> 
> And we know he sure as heck CAN'T be talking about density range...
> Todd

Todd,

Nice quote.  Somehow I must have missed it looking around for dynamic range
references.  I wonder if anyone has enough rapport with him to get him to
say more, clarify "longer".

I'd like to take a stab at it though.  Naturally, I'm just reading what's quoted
and I just "interpreting" what I "think" he is saying and means.

One thing is that starts off referring to the DyR of the human eye and the DyR
of film.  The long DyR of the eye seems pretty analogous to just the range
of light that we can see -- the deep shadows are a "long" ways from the
"bright highlights".  Likewise the shorter DyR of the film is consistent and
analogous to the useful density range of the film.  So far I think this is basically
my intended interpretation.  (Its probably vague enough to come up with others).

Now he slips into the S-curve density curves -- saying "the highlights and shadows 
are subject to compression".  What is he trying to say??  Well I think he is saying
the end points are blocking up so that the density range of ordinary photo paper
that really has useful information is somewhat shorter that the total density range.
In other words, the "dynamic range" of ordinary photo paper is shorter because
of the S-curve nature rather that a linear nature i.e. the DyR doesn't really
go all the way out to dMin and dMax.  I think the next sentence
touting the linear nature of Piezo is saying that he considers the dynamic
range of Piezo to be longer because the linear section goes all the way out to
dMax and dMin.  I think a real key notion if that dynamic range always 
refers to the "useful" portion.  If we are talking about something with density
(film or paper) we should exclude densities that have no information.

I wonder if Cone would agree with my interpretation.

Roy