Digital BW, The Print

----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Wednesday, April 03, 2002 9:15 PM
Subject: RE: For Roy Re: [Digital BW] Thoughts about Imaging


>
> > Ratio of minimum and maximum contrast.
>
> B-b-b-b-b-but Martin, isn't maximum contrast (dMax - dMin), and minimum
> contrast the "smallest discernable [tonality]"?

Austin,

The problem I have is what is doing the discerning. I know that my eye
cannot discern as small a change in tone as a densitometer for example. Also
if the print changes tones in increments smaller than my eye can detect,
then the minimum contrast would be determined by my eye and not the print.
The idea of min/max contrast perhaps makes some sense to me but I am still
skeptical of how it could be put to good use.  I need to mull this over a
bit.
>
> > This fulfils the basic definition and is not as obtuse as it would
appear
> > from the DyR equation.
>
> For photographic use, I'd agree with that!
>
> > The equation is just a subtle change on
> > the basic max
> > to min ratio
>
> What's the change?  The definition of "min" and "max"?

No it is a clarification of what we are taking the dynamic range of. The
dynamic range of contrast would not appear to be the same as the dynamic
range of density.
>
> <snip>
>
> > Austin is
> > not wrong in
> > applying his contrast ratio to a photographic print but he has failed to
> > demonstrate how this would be done or what value it would have when
> > comparing two printing mediums.
>
> For me, that's a separate issue...I wanted to get to the point where the
> basic concept was understood first.  I take it you now understand/agree
with
> the statement "dynamic range of a photographic image is (maximum contrast
/
> minimum contrast)", and not the same as the density range?

I better understand the relationship you are trying to define but I have
long realized that it was something different from the density range. Now as
to which is the more useful concept I am not sure. Would it be inappropriate
for a print to have more than one dynamic range? Each for different
properties or relationships between those properties? Or perhaps the word
dynamic range has been used in so many different ways we need some new
terminology?

Martin