Digital BW, The Print

Hi Clayton

The immediate answer to your question at the bottom is that there is nothing
you can do about it because you (much like Paul) can't get inside the Epson
driver.  In your workflow, the Epson driver - not you - decides what to do
when it gets a (normalised) pixel value of 0 or 1 and all points in between.
I, nor you, don't know what transfer function is within the black box.  This
is analogous to letting a camera do the RAW conversion.  The transfer
function is not open and there is within an implicit trade-off between
dynamic range and contrast.  As a result, if you were to start anew you
print an image and look at it.  Apply a curve to adjust it and reprint.  At
this point there are two transfer functions at work:  the curve you just did
in PS and the curve embedded in the driver.  It's quite difficult to
visualise something you can't see.  Rather you develop feel by iterative
experience. In an open RIP we get the opportunity to define the transfer
function, potentially making it better suited to a more tonal range
conscious workflow.

Your workflow is the simplest of them all.  You work with one ink (until a
better one comes along).  You work with a box that you can't alter nor see
inside - you take what it gives.  And you change paper to change your white
point and dMax.  Nothing wrong with this - it is very simple. But again your
PS curve is not done with the tonal range limits of the printer/ink/paper
combination at the forefront.

An interesting test would be to print a step wedge in the normal fashion and
measure the results.  Then use an abrupt clipping curve to constrain the
image file to the tonal range of that same combination (say output values of
45 to 243 only, roughly EEM) and print this.  In either case the range of
tones able to be produced by the printer have not changed and in one case we
have simply fed it an in-range image.  In the other we have purposefully
sent a range of tones that we know can't be reproduced.  How do the two
images compare?

Cheers

Steve


> From: Clayton Jones <cj@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Fri, 03 Dec 2004 17:16:41 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: Re: [Digital BW] Tonal range and linearization
> 
> 
> 
> Hello Steve,
> 
>> Actually let me go one step further.  When Mr Adams made his
>> prints with the Zone System he could be assured that his Zone
>> V ended up where he wanted it (and he could alter print
>> gamma/contrast) around it.  As currently configured, mid grey
>> shifts when we load one print curve vs another - even though
>> it did not shift in the digital negative.  Unfortunately, I
>> believe, we have gone a little backwards in our rigour and
>> method.
> 
> I have been following this with interest (I especially love your "fume
> room" LOL! and enjoyed your Adams and Weston quotes).  You make some
> very interesting points.  They seem to have good meaning but I confess
> I am missing something when it comes to imagining practical
> application, and it may be caused by the way I work.
> 
> My BO workflow is a very intuitive one, and my fume room thinking has
> adapted nicely to it - IOW, I still think in S-curve terms as I work.
> Further, because BO doesn't allow changing tone (color), it requires
> using different papers to achieve various warm/cool results.  This is
> another thing about BO that is somewhat analogous to wet print work.
> I have a small handful of favorite papers.
> 
> I'm finding that my S-curve thinking adapts nicely because once I've
> finished working up an image using EEM for proofs, I can now print it
> on any other paper by applying a curve adj layer for whatever papers I
> want to try, and then choosing the appropriate curve each time I make
> a print.   For example, for an image I've been using for some
> experiments I have curves for BO Merlin, BO Condor, and UT7 Condor.
> Another one has curves for BO PR, BO Aurora and UT7 PR, and so on.
> These curves are attached to the image and I just switch on the one I
> want.
> 
> I have arrived at this methodology through the photographic intuitive
> process as Claude described, and am now at the point where I can
> devise a new curve very quickly (tweak the curve until the print
> matches the contrast of the EEM proof using very small quick prints).
> I have gotten familiar with the properties of the few papers I like
> and pretty well know where to start and am already "in the ball park"
> the first go-round.
> 
> I find this to be a very enjoyable and satisfying way to work, and I
> think it's partly because it's very similar to they way I worked in
> the fume room (love that!).  I was a Fred Picker type Zonie, which I
> found to be a good balance between being particular about results and
> KISS.  I still feel like I'm working photographically, and my mind is
> not full of gamma/black point/etc concepts.  I mentally see each paper
> in terms of its S-curve characteristics and tone (how it renders
> Eboni), much as I did in the fume room days.
> 
> The point of all this is I'm wondering how your ideas can hook into
> what I'm doing.  How can I benefit from it?   Your concepts are
> expressed in very technical terms, but can they be applied in my
> intuitive S-curve way of thinking and adjustment curve workflow?
> 
> Regards,
> Clayton
> 
> 
> Info on black and white digital printing at
> http://www.cjcom.net/digiprnarts.htm
> 
> 
> 
> 
> 
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