Digital BW, The Print

Martin,

> Todd,
> 
> I just want to point out that dynamic range in photography is generally
> discussed along with contrast. You don't need to get everything into a
> single value.

Okay, that makes it more useful.

I'm re-ordering your paragraphs a bit below, I hope you don't mind.

> What you mention below seems to be simply an issue of contrast. The response
> to exposure may become steeper or shallower depending upon the grade of the
> paper but once the print is a done deal the original grade is no longer a
> contributing factor. You are right and contrast is independent of density
> range and of what is commonly called dynamic range.

Yes, it's just an illustration of "internal" vs "external" contrast, but I
wanted to include an example where tones can be lost while maintaining
(max/external) contrast.
 
> Phil Davis discussed this at great length in "Beyond the Zone System" with
> lots of curves showing how Scene Brightness Range maps to the negative by
> way of the film's exposure response curve and how the negatives density
> range maps to the print by way of the paper's exposure response curve.

Yes, it sure takes curves to characterize a non-linear workflow.
 
> It is interesting that he manages to get through 200+ pages of photographic
> sensitometry and never even uses the term dynamic range.

Hmm.

> Austin is discussing an interesting relationship but it is not the
> relationship commonly called dynamic range in photography, i.e. the ratio of
> lightest and darkest which is frequently quantified as the density range. I
> believe that the property he is discussing is of interest but I don't see it
> as a new or expanded definition of this ratio.
 
> I have to agree with Roy that it serves little purpose to redefine dynamic
> range as something different than how it is commonly used in photography. I
> think that we would be better served at this point if there was a different
> term for the relationship Austin is describing. I know Austin will not like
> this but if the term dynamic range has already been appropriated, rightly or
> wrongly, trying to switch just adds to the confusion.

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

PS, If I look like I'm flopping from one side to the other on this I am.
Actually, for the moment I'm just thrashing around inside the issue, without
taking a side.


> Martin
> 
> P.S. Since when do prints have pixels? <G>
> 
> ----- Original Message -----
> From: "Todd Flashner" <tflash@...>
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Sent: Friday, April 05, 2002 3:16 PM
> Subject: Re: [Digital BW] Thoughts about Imaging
> 
> 
>> Roy,
>> 
>> I'm sensing that some of us have locked horns when we are probably more in
>> agreement than out of agreement. Perhaps if we all surrender a little
> ground
>> we can turn this back into a useful discussion.
>> 
>> Is it possible that *some* people used the term dynamic range to describe
>> something one step more complex than density range? I think behind
> Austin's
>> absolutist rhetoric that is what he's saying.
>> 
>> Working with my sense of logic, which doesn't prove anything, let's look
> at
>> the bigger picture. Lets consider a common situation we as photographers
>> experience. Say through careful exposure and development we have a
> negative
>> with a beautiful delicate distribution of tones throughout it's useful
>> range. It would perfectly fit all it's tones on a given grade 2 paper.
> Let's
>> say that print's density range would be 2 units. If we could measure the
>> print on a pixel by pixel basis it would yield a perfect distribution of
>> tones in a histogram, right to the ends with no clipping. We could then
>> print that negative on a grade 3 paper, which may also yield a density
> range
>> of 2 units, but we "clip" tones from the image on both ends due to
> increased
>> contrast. It's histogram shows the clipping accordingly. We could even
>> extend the scenario to where we keep the print on grade 3 paper, but dodge
>> the shadows and burn the highlights, thus maintaining a higher internal
>> contrast through the midtones, without clipping the ends. It's density
> range
>> is still 2 units, and it's histogram looks more like the grade 2 print, at
>> least at the ends.
>> 
>> Something *is* different in each of these prints, but it is not the
> density
>> range. Is it possible that some people would say that the grade 2 print
> had
>> a greater dynamic range than the straight grade 3 print, and that the
>> manipulated grade 3 print might have had the greatest dynamic range of the
>> three? If not dynamic range, what would be that term?
>> 
>> Todd
>> 
>> 
>> 
>> 
>> 
>>> --- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin"
> <darkroom@i...>
>>> wrote:
>>>> Roy,
>>>> 
>>>>> So, how can we here is our niche, talk about coming up with a new
> idea,
>>>>> new concept of what "dynamic range" means?
>>>> 
>>>> No one is coming up with any new concepts...  "We" are merely pointing
> out
>>>> that the term has been "misapplied" in this "field", and that it
> attributes
>>>> a different property than, though is loosely related to, density range.
>>> 
>>> Austin,
>>> 
>>> I think Todd's "lost in the trees at points and loose sight of the
> woods"
>>> quote is right on.
>>> 
>>>> 
>>>>> We a just a part of a large
>>>>> community of imaging that long time ago has defined and has commonly
> used
>>>>> this term to mean sometime very specific.
>>>> 
>>>> Can you show evidence of this?
>>> 
>>> I think the Ansel Adams book and the Real World Scanning references were
>>> pretty relevant.  I'm glad to see you have read the scanning book.  You
>>> quoted one sentence that contained "dynamic range describes the actual
>>> limits of how many tones the scanner can really differentiate from light
> to
>>> dark".  You seem to be associating:  dynamic range <--> how many tones,
>>> when I think the real association is:  dynamic range <--> actual limits.
>>> Reading just this one sentence might be a little ambiguous, but read the
> whole
>>> paragraph.  Immediate following this sentence is the staircase example:
>>> dynamic range <--> height of staircase,  bit depth <--> number of steps.
>>> Later on he compares a scanner with "enormous dynamic range but only
>>> 256 steps" and a scanner with "lots of tiny steps and tiny dynamic
> range".
>>> There's no way to interpret these two examples to mean dynamic range
>>> is a measure of number of tones or steps!
>>> Do you wish to claim that this book and the three guys who wrote
>>> it are wrong and misuse and misdefine the term??
>>> 
>>> If you look at the Adam's book there's a diagram that explicitly shows
>>> "dynamic range".  He's talking about exposure and shows very clearly
>>> dynamic range going from about Zone I to Zone IX saying its the "useful"
>>> range of light values in the scene.  He even mentions how this dynamic
>>> range of light values maps directly into the range of "useful" densities
> on
>>> the negative.  Would you like to claim he's all wrong, too?
>>> 
>>> Please consider your position as it relates to these references.  These
>>> are both very explicit references to dynamic range as it relates to
> imaging.
>>> 
>>> Regards,
>>> Roy
>>> 
>>> 
>>>> 
>>> ... monitor stuff snipped
>>> 
>>>> 
>>>> Austin
>> 
>> 
>> 
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