Digital BW, The Print

> From: The Wogster <wogsterca@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Fri, 03 Dec 2004 09:57:44 -0500
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: Re: [Digital BW] Tonal range and linearization
> 
> 
> Steve Kale wrote:
>> Tyler
>> 
>> Yes I agree that there are many ways to replicate WYSIWYG.  But this
>> proposed workflow is not intended to revolve solely around that.  It is
>> intended to more clearly and explicitly relate the tonal range of the
>> printer into the final steps of the workflow process.
>> 
>> The big problem with today's setup is that there is a hidden transfer
>> function (a remapping of pixel and their density/luminance values) from
>> workspace to print space which is HIDDEN from the view of the user - it is
>> imbedded in the RIP code and curve generation process.  It does not conform
>> with the user's workspace.  What's more, the nature of this transfer
>> function - it's end points, representation of mid grey, and all other points
>> between - is different for every paper and ink combination!  Move from a
>> curve for matt paper such as EEM to a glossy "curve" on glossy paper and the
>> way all your mid tones are reproduced is different.  A PS adjustment curve
>> for one will not give the same result for another.  Over the last 2 years I
>> have witnessed hundreds if not thousands of posts on this forum which are
>> the symptoms of this problem.  People get their prints looking nice on
>> screen using the full tonal range available to them and then send it to the
>> printer without any understanding of the tonal range limitations of the
>> paper/ink combination they are using nor the way the printer will remap
>> their original (file's) tonal range to fit the narrower one.
> 
> Isn't photographic paper the same?

Yes and no. Each photographic paper has a defined and published tonal
response curve with its limits (dMin and dMax) and contrast or gamma.
Different photographic papers were made with different contrast ratios
BECAUSE that was the only way to alter contrast (one also could use a
different negative development but once the negative was developed the only
way to alter contrast was to select a different paper).

Digital provides a much more satisfying and flexible method for altering
contrast - within the digital file itself.  This is analogous to being able
to change the composition of the developed negative.

> 
> Part of the problem with the current process, is there are no givens....
>     People think that they can change parts of the printing process,
> without needing to think about how that will change the process.
> 
> For example, say I have a darkroom print, printed on Ilford Multigrade
> RC paper, processed with Ilford's Multigrade Developer,  with copious
> notes on the way it was processed.  Now I move to  Agfa Multicontrast
> Classic, and switch to to Kodak Dektol as the developer, following my
> notes, will the two prints look identical.  Slim chance to none, the
> different papers have different sensitivity curves, and the developers
> work differently.
> 
> In the fume room, they resolve this, by only using only one or two
> papers, in fact you would probably only keep one type and brand of
> paper, with some in glossy, satin/pearl and matte finishes.  You would
> learn how the paper reacts to changes, and get fairly good after a
> while, at knowing what the result would look like, seeing the negative
> on the light table.
> 
> 
> Same goes for digital printing, if you change the paper or ink or both,
> you should expect the result to look different.

But of course!  At a minimum they have a different dynamic range.  The
question is whether one SHOULD expect the gamma/contrast within the dynamic
range to change.  In a digital world this is unnecessary because we have a
much better method for altering the image file (the digital negative).
Worse yet - you would not want any change to not be transparent.  Better to
keep print space gamma at a known constant and alter the digital negative.


> This is why you would
> change the paper or ink or both in the first place.  For example, if I
> have a print on Kodak Ultima Picture Paper, and pop in a sheet of
> Hahnemmühle Photo Rag, and print it again, I should expect to have a
> different result.  If I know how those two papers work, with that
> particular ink, in that particular printer, then I will know how I need
> to adjust the image for printing.  The other option is customized
> curves, so that they react the same......
> 

When you swap papers are you aware of the exact change in tonal range and
more importantly to what extent and how the relative tonal range has
precisely changed?  I doubt it.  Rather through trial and error you (like
me) get a feel for the change and work against it.  Much like Mr Weston and
his light meter....

Once again:  in a darkroom world we had to change print space gamma because
once developed we had no mechanism for altering the negative.  In a digital
world, we have very precise tools for altering the digital negative.  It is
better that other factors remain constant and precisely predictable, or at
least very transparent.

Steve