Digital BW, The Print

> 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.

> I think that I may have a fresher perspective on the
> situation but I will put that in another post.

OOOOHHHH NNNNOOOOO, NNNNOOOOTTTTT  AAAAANNNNOOOOTTTTHHHEEEEERRRR
PPPPOOOOOSSSSTTTTT! ;-)

> I note that there may be some confusion on terminology. I have been using
> Dmin and Dmax as minimum Density and maximum Density. You have been using
> dmin and dmax which could be taken as the delta of minimum values
> and delta
> of maximum values.

I believe dMin and dMax are very clearly defined, and I believe they are
simply the "static" value measured of the darkest and lightest part of the
image.

> > Whether noise is near 0 or not, density range and dynamic range
> are never
> > the same, simply because their units of measurement are entirely
> different.
>
> But one may become of no practical interest in evaluating the system while
> the other still is of use.

That's OK, but I believe the two statements (yours and mine) are two
different issues.

> If I believe the number is infinite or appears to the eye to be infinite
> then comparing them has no meaning. I believe that this was my original
> point that silver and inkjet were the same in this regard.

> The fact that tones are more discernable to a densitometer than are
> discernable to the human eye has no effect on the visual
> presentation of the
> print. It is irrelevant for practical photography and print making.

Hum.  That distinction wasn't made, that I remember, until way later on in
the conversation.

> > There are also prints that exist that
> > have a number of tones that we can differentiate.  How do you "describe"
> the
> > difference in number of tones?  NOT with density range...but how?
>
> Since you can make any print you want and pick what tones you what to use
> you could choose to make a print with a specific number of tones. As in a
> print of a step tablet. My understanding was that the discussion was about
> the print mediums of inkjet vs. silver. No individual prints or
> that we were
> discussing full range and tone prints that contain all the tones available
> to each system

That was merely an example, trying to show that dynamic range can be
perceived/discerned in a print.

> > You've also shifted the discussion from your original claim, and are now
> > saying dynamic range isn't relevant because we can't see it.  The
> > interesting part is, you don't know that we can't see it, and you can't
> make
> > the claim that we can't see it in EVERY image printed, now can you?
> >
> 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.

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?

> > >
> > > As in continuous tone? <G>
> >
> > That doesn't make it continuous.  Continuous is merely a perception...so
> > whether it "appears" continuous is solely based on the sensor used to
> > perceive it.
>
> Continuous is a mathematical function and not a mere perception.

The point is it doesn't exist in reality, WRT the discussion we are having.
It would have been better if I said "concept" not "perception".

> Although only what we perceive is of any interest to us a
> photographers and
> printers. If there are imperceptible changes, why would they effect the
> quality of our prints.

Now you're adding qualifiers to your original statements...

> > Neither chemical prints, or inkjet prints ARE in reality
> continuous tone.
> > As I've pointed out, you would need a sheet of paper of infinite size to
> > represent your definition of continuous tone (being entirely stepless),
> and
> > that does not exist.
>
> If it is stepless any size paper will do.

Absolutely wrong.  There are only so many atoms in a given space.  There are
NOT an infinite number of atoms on a 4x6 piece of paper, now are there?

> > As I've said, provenance is the equation, period ;-)
>
> So it is okay not to have an equation in the definitions you like. You
> objected to the lack of equations in all the others.

But they aren't "equations", they are words describing equations in
pedestrian terms, with no qualifications for the terms.  An equation, of
this nature, requires qualifications of the terms, both in meaning and units
(if applicable).  That's common mathematical courtesy ;-)

> > > > Er, yes I did.  I gave you an example using 0.01D as the "noise".
> > >
> > > Hmmm. Somehow an example just doesn't satisfy like an experimental
> value.
> > > What if I say for example that the noise in a silver print is
> > > 0.00000000000000001 dB can I use that? <G>
> >
> > If you want, I have no problem with you using ANY value, all
> I'm trying to
> > get you to understand is chemical prints HAVE dynamic range.
>
> Well at this point let's say I don't care unless the value of the noise is
> large enough so that your DyR equation gives us a value that will allow me
> to say one system makes a better print than another.

That is already done.

> If both have a finite
> number of tones and we can visually see this in the prints then it would
> seem that DyR is important. If we cannot distinguish a finite number of
> tones visually, not with an instrument, then the DyR will not help us
> evaluate the two.

Well, if we find out the number is very high, and that meets our needs, than
that HAS helped us evaluate the two, has it not ;-)

Also, see my comment about tones within a limited range above.

> > > I have no reason to believe that noise exists everywhere and I can't
> take
> > > that as a given.
> >
> > OK, but I can state unequivocally it does...at least in the physical
> world.
> > Noise doesn't exist in the number 1, but trying to measure 1", it does.
> Can
> > you name any physical property that doesn't have any noise?
>
> Length has no noise. The measurement of length has noise. You continue to
> confuse the measurement of something with the thing itself.

No, I'm not "confusing" measurement with the thing it self.  We have been
talking about measuring/perceiving things here.  Additionally, length of any
object DOES have "noise", whether you measure it or not, even if you are
talking about distance between two atoms...which, BTW, have physical size.
Anything that has physical properties to it has "noise".  Things are also
not in "stasis", they are in constant motion.  Now, whether this noise is
perceptible or not, is another issue...but you were talking about
"existence", not measurement...and I believe I've shown that even in
existence, "noise" exists.

> >
> > > The noise you described earlier would be
> > > variations within
> > > a given paper base rather than the variation from brand-to-brand
> > > and may be
> > > so small as to push the results of your equation towards infinity.
> >
> > Source of noise isn't relevant to the dynamic range OF the print, the
> > print's dynamic range is the print's dynamic range,
> irrespective of where
> > the noise came from.  It is relevant to the dynamic range of the system
> > though.
>
> I keep offering to consider what the noise would be and how we
> could measure
> it in order to determine the importance of using dynamic range in
> evaluating
> prints mediums and you say the source of the noise is irrelevant?

Yes, the source of the noise on the print IS irrelevant.  The noise IS the
noise.  When you weigh your self, does knowing where the weight came from
change the measurement?

> I begin to
> suspect you are not certain that the noise can be determined or
> measured.

Not at all.  AND this is all a red herring to the original claim you made,
and that I disputed, and still dispute...the dynamic range IS entirely
different than density range.

> Can you actually calculate the dynamic range of a print

Yes, but I don't believe you HAVE to calculate it for it to exist.  The fact
that you can see the difference between two prints makes it useful.

> and is
> that value of use?

Yes, it certainly can be.

> Are you really interested in doing this? Do you really
> want to determine if a silver print or an inkjet print has more tones or
> not?

Yes.  I believe, if it hasn't already been done internally by Kodak or
someone else, it would be very very interesting.

> > > Well I am a very practical engineer. Chemical process and project
> > > engineering remember, so I want to know all those details.
> >
> > I am a very practical engineer too...I like to understand what
> it is I am
> > trying to do here before getting into the details.  You and I haven't
> worked
> > out the basic concepts here, so the details aren't relevant.
> Perhaps you
> > are having trouble seeing this through the details?
>
> If you cannot provide enough details to practically implement your ideas,
> what is the point?

The details are meaningless unless you understand their significance and why
they are important.

> > > True but you need a meaningful value for the noise to do that.
> >
> > Yes you do.
>
> Exactly. Until you do have a meaningful value what is the purpose of
> comparing the DyR of a silver print to an inkjet print?

The issue, with you and me, is that you claim that dynamic range of an image
is the same as density range, and I claim it is not.  What on earth good is
a "value" if you can't get beyond that?  Are you trying to claim if there is
no "meaningful VALUE" that it doesn't exist?  Please.

> > > > > If you don't have the
> > > > > values you
> > > > > need to apply your dynamic range equation, what use is it?
> > > >
> > > > Having a "correct" value or not doesn't mean it doesn't exist!
> > > >
> > > No but lack of a correct value makes it of little practical use.
> >
> > Yeah, but I'm trying to convince you it even exists, not anything about
> the
> > practicality of it...that's a waste of time until you understand the
> concept
> > and it's existence!
>
> I have already stated several times that I am willing to assume that your
> concept is entirely correct and have tried to move on to look at what the
> practical implications of using it would be.

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 ;-)

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.

> 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) ;-)

Regards,

Austin

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.  Don't confuse exposure latitude and density
range here with dynamic range, a lot of people do ;-)