Digital BW, The Print

--- In DigitalBlackandWhiteThePrint@y..., "hsitz" <hsitz@n...> wrote:
> If you'll read the brief article at this webpage carefully, you'll 
> see that it's in agreement with what Austin has been saying.
> 
> http://www.library.cornell.edu/preservation/tutorial/intro/intro-
> 05.html
> 
> 
> The two pictures of the buildings are a perfect illustration of 
> images with identical "density range" (i.e., they both go from full 
> white to full black), but with different "dynamic ranges".
> 
> Also, don't be fooled (as I was, at first) by the phrase, "the 
> dynamic range does not automatically correlate to the number of tones 
> reproduced".  That phrase isn't saying that Austin's understanding 
> of "dynamic range" is wrong.  It's saying that Austin' understanding 
> is right, but that an image system's dynamic range is merely 
> potential, and that it may still produce images that don't make full 
> use of its dynamic range.  -- Herb

Hi Herb,

I'd seen that page before.   I think you're going to have a hard time
proving much one way or the other with this description.

Like you said both images go from black to white, but you are also looking
at both images on your monitor, right.  Your monitor displays up to 256
levels of gray.  Maybe you can't distinguish them all but whatever ones
you can distinguish are going to be the same for both pictures.  I.e.
counting number of grays in the two pictures is going to be almost 
entirely dependent on your monitor.

For anyone who has done a lot of darkroom printing, there'a an immediate
response to those two pictures.  The bum one is printed too contrasty.
Its done with the wrong grade paper.  The description of what's wrong
with it, is right there -- the lack of detail in shadows and highlights.
This is exactly too contrasty.

They talk about "limited dynamic range".  What do they mean?  I think
the way they are using the term is often found.   I don't they are
really talking about the grays in the final print (or jpg).  I think they
are interested in whether the distinguishable grays in the original
scene show up as distinguishable grays in the final print.  The problem
is the distinguishable grays in the shadows of the original scene show
up as way too dark in the print.   My translation is that the
dynamic range of the original scene (we would have seen shadows and
highlights) is poorly represented in the dynamic range of the final
print.  In other words the lower end (the dark parts) of the print come
from a much higher (brighter) portion of the dynrange of the original
scene.  The part of the original dynrange going from the bottom to
the brighter parts (referenced immediately above) is unfortunately
bunched all together into the very darks in the print i.e. no shadow
detail.  Or final translation: A limited portion of the dynamic range
of the original scene is show in the dynamic range of the final print.

Hopefully I said that clear enough, a picture would be so nice!
Semantics is tricky here, but people use terms without being
very precise sometimes.

Roy