Digital BW, The Print

Austin,

I am not sure I have much to add at this point. Still mulling things over.
Charles Francis wrote me off list and brought up the term "internal
contrast(s)" which I am familiar with. Sometime just thought of as "local
contrast". This can be a problem in prints where the overall contrast
balances out nicely in the print but there will be some area typically with
fine detail of interest that covers just a tiny portion of the density range
and winds up looking like mud. This seems to be a common problem with
contracted developments where there has been a strong compression of tone
from the scene to the negative. Is this in anyway related to what you see in
the quality of the tonality of the print?

Martin

----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Thursday, April 04, 2002 8:41 AM
Subject: RE: For Roy Re: [Digital BW] Thoughts about Imaging


> Hi Martin,
>
> > > > 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.
>
> I understand and agree.
>
> <snip>
>
> > > > 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.
>
> Hum.  I had to read that a few times.  In a way I agree.  Density is a
> static value, and really can be only a single value in and of it self
> (though it's understood it is a relative value, based on a calibrated
> density scale...).  Contrast isn't static...it requires another thing to
be
> contrasted against.  In that, I agree...and fits the term "dynamic" much
> better.
>
> > > <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.
>
> We are in full agreement and understanding here ;-)
>
> > 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?
>
> I do believe the dynamic range of the printing system can be determined,
as
> well as of the paper one is printing on.  Quite easily in fact.
Obviously,
> as has been well pointed out, the actual dynamic range of A print, in and
of
> it self, is a far more complex issue.  I agree.  I have to sit with that
for
> a while when I get some time.  I believe I understand how it can be done,
> but obviously, haven't spent the time doing it.  It would be interesting
(at
> least to me) though.
>
> Regards,
>
> Austin
>
>
>
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