Digital BW, The Print

> Okay I will add:
>
> From X-rite\ufffds \ufffdThe Color Guide and Glossary\ufffd
>
> \ufffdDynamic Range: An instrument\ufffds range of measurable values, from
> the lowest
> amount it can detect to the highest amount it can handle.\ufffd

Yeah, what's wrong with that?  It's exactly as I have said.  The lowest
AMOUNT (not least amount mind you) it can detect IS the "smallest
discernable signal".  Highest AMOUNT it can handle is still a bit dubious.

As I've said, provenance is the equation, period ;-)

> From CCD Direct:
>
> \ufffdThe dynamic range is often represented as a log ratio of well
> depth to the
> readout noise in decibels. For example, a system with a well
> depth of 45,000
> electrons and a readout noise of 15 electrons would have a dynamic range =
> 20 log (45,000/15), or 69dB.\ufffd
>
> http://www.ccddirect.com/online-store/scstore/dynamic.html
>
>
>
> You never did say what you thought of this last one which seems to be in
> your field.

It's fine, it includes noise, as it should, and the equation is correct...
The RANGE is 45,000, and the noise is 15, and they divide range by
noise...exactly as I have been saying every time...  A depth of 45,000 means
a Max of 45,000 and a min of 0...

I didn't comment on it because it's entirely correct, and fits everything
I've been saying to a "T".

> > > You have not been able to supply a value for the noise in your
> > > equation yet
> > > so how did you manage that.
> >
> > 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.

> 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?

> 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.

> 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?

> True but you need a meaningful value for the noise to do that.

Yes you do.

> > > 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 did not mean to impugn your printing skills.

I didn't take it that way at all...it's an entirely legitimate
question/concern!

> No. That would be terrible ineffiecient and waste of valuable time.  <G>

Doesn't that create more noise in your system though, or are you just so
damped that it's just all din ;-)

> I'm just on the west coast and a bit of an insomniac, and can keep posting
> past your bed time but you leave me a whole stack to look at with
> my morning
> coffee.

Oh, sorry, I don't drink coffee ;-)

BTW, do you have children?

Regards,

Austin