Digital BW, The Print

----- Original Message -----
From: "Austin Franklin" <darkroom@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, March 31, 2002 8:55 AM
Subject: RE: For Austin Re: [Digital BW] Is dynamic range more important
than density range?


> > I am not
> > sure we are doing much more than rebutting each others statements
> > endlessly
> > at this point.
>
> I do believe you're right.  You and I haven't really brought anything new
to
> our "arguments", per se, but I also believe other very interesting points
> have been brought throughout the discussion.

Austin,

At this point I think I will just pick a couple of things that appear to
have a different slant and let the rest go as I am afraid we are getting
repetitive. Perhaps to continue we need to simple make some fresh post.
Continuing these individual threads to such great length seems to lose a
great deal of the continuity of thought. I have read all your replies so I
am not ignoring what you wrote.

>
>
> > >
> > No, for the sake of ending the debate over infinite tones, I asked that
we
> > consider the case where there are a finite number of tones and
> > expressed my
> > opinion that if the number of tones is very high then dynamic range is
no
> > longer of practical interest.
>
> But now you're putting a qualifier on this.  The original statement was
that
> density range and dynamic range are the same, and they are not.  Whether
you
> can perceive it with your eyes doesn't mean it doesn't exist.  It really
is
> two entirely separate issues.

The issue was number of tones and we got stuck over the definition of
dynamic range. In photography, rightly or wrongly, dynamic range has
frequently been defined as the density range which is an expression of the
reflectance ratio. The one thing I would ask we keep in mind is that this is
a useful relationship regardless of what we choose to call it. Your equation
defines a different relationship but shares Dmin and Dmax as key values.
>
> There is also another issue that hasn't been brought up.  If the eye can
see
> 100 tones, what EXACTLY does that mean, with regard to a print.  Here are
> two extremes.  We have a full tonal range from dMin to dMax, where dMin
and
> dMax are at the limits of the printing process.  Second print, has 100
> tones, but they lie in a VERY limited range of the overall ability of the
> printing system...the dMin and dMax of the actual print are much much
> smaller than the dMin and dMax of the ability of the printing system can
> achieve.  What do we see?  I believe we CAN see 100 tones, if in the right
> light...simply because of how our eyes work.  Now, I honestly don't know
the
> answer to it, but the point is, if what I am theorizing is true, the
dynamic
> range becomes more significant, than if we just assume 100 tones across
the
> entire printing range is sufficient...  Unnastan?

I am not sure but you may very well be right. By varying the lighting you
are varying the amount of reflected light that reaches our eyes. Under a
given lighting situation our ability to discern between two similar tones
has a limit. If we start at one end of the scale where we can first discern
a tone as different and proceed toward the other end of the scale until we
can no longer discern a difference there is a finite set of 99 tone pairs.
If when we reach that limit we have also just reached the other end of the
tonal range of the print then it is matched to our eyes and those viewing
conditions and is perhaps very appealing visually. If we reach the end of
those 99 tone pairs and have not reached the other limit of the prints tonal
range then we can't see the detail and the print does not look so good or
appears to be missing tones. Also if we reach the end of the print's range
and have not reached 99 tone pairs the print may seem flat and dull.

This would lead to the idea that under one set of viewing conditions an
inkjet print matches the range of our eyes and in another set of viewing
conditions a silver print matches the range of our eyes. Reverse viewing
conditions and the silver print appears to lack shadow detail and the inkjet
print seems to have weak blacks looks washed out. This seems likely to be
true but I don't know what we do with the information other than to keep it
in mind.

I suspect that in normal lighting the 1.4 to 1.6 Dmax of inkjet is below our
threshold and the 2.2 to 2.4 of silver exceeds it.

Then in terms of a system made up of the print, our eyes and the viewing
conditions your dynamic range equation becomes more interesting. The
difficulty is that our prints need to look good in a reasonably wide range
of viewing conditions and to a reasonably wide ranges of eyes (and I bet
there is a lot of variation there!)
>
>
> That's the first I've read of that!  If that's the case, then we can move
on
> past that point...perhaps you have, and I just didn't know it yet ;-)
I'll
> accept your premise that you accept my premise...but I'm not going back
and
> re-writing the top part of this post in light of that...all right, may be
> I'll skim it ;-)

Well like I said, all these long threads (posted out of sequence courtesy of
Yahoo) has lead to a lot of confusion.
>
> It appears that you're at the "is it useful" and "how do we measure it"
> stage, right?  I believe I've said yes, and shows why it may be to the
> useful question, and I believe I've given an example in a post to Todd on
> how to measure it...but I also believe that measuring it may not be
useful,
> the fact that you can visually distinguish the dynamic range of two prints
> serves the concept well.

The problem is that visually distinguishing it without being able to put
some numerical values to it seems awfully subjective and open to confusion.
>
> > No I got too old and missed my chance. I do have a 4 month old
> > Scottie and a
> > 3.5 month old Westie puppies at the moment to keep me busy.
>
> We have Airedales (as well as children) ;-)

Airedales are great! Kids, ummm..... ;-)
>
> BTW, I just thought of a very good dynamic range comparison.  A Polaroid
> print with a chemical print.  Also, positive film vs negative film.
>
> It is, I believe, well known that positive film has a lower dynamic range
> (less tones) than negative film.  I know I have noticed the difference,
and
> yes, I've shot the same scene.

I keep meaning to give their P/N film a try but I have no experience with
it. Don't you have to use a different ASA for P or N exposure?
>
> Don't confuse exposure latitude and density
> range here with dynamic range, a lot of people do ;-)

Oh I would never do that.

Best,
Martin