Digital BW, The Print

Hello Kevin,

>I've heared you mention creating a contrast curve to make your 
>Aurora print match the EEM proof.
> 
>Is it not possible to simply add/+1 or +2 to the Contrast Setting 
>in 2400 ABW Color Management?

No this really doesn't do the job.  It's too linear - by that I mean
it applies a change according to a fixed formula of some sort that is
always the same may and may not match the needs of the image.  It's
not just a matter of more or less contrast.  Here's an example:

Say you work up an image on EEM and you are perfectly satisfied with
it.  You print it on Aurora and it looks lower in contrast in general,
and perhaps some midtone areas are a tad too dark.  Highlights look
ok. So you add an adjustment curve and attempt to make the A. print
look like the proof.  A typical contrast curve has an S shape, so you
pull the low end down a bit and raise the center a tad, then make a
new print.  Closer, but now some high zones have been raised too much.
 So you add another point up there and pull that back down and make
another print.  Ahh, much better.  You keep doing this until the A.
print is an exact or very close match to the proof (with experience
you get very good and quick at this, especially as you get familiar
with the response of papers you use regularly - you intuitively know
how much to move a curve point to get what you want).  

The curve you end up with is rarely symmetrical, and most likely very
different than the curve the driver contrast control would have
applied.  Not only that, but go through the same process with another
image and the curve will be different.  At the bottom of article #9 in
the section "Matching the Final Print to the Proof" there are two
screen shots with examples of these paper curves.  They are quite simple.

BTW, I save this curve with the image without merging it.  This keeps
the master image unchanged, and if you ever want to make another proof
just deactivate the curve and print on EEM.  If you ever want to print
it on another paper, say VFA, you can deactivate the Aurora curve
(make a new proof if you haven't saved one) and make a new curve for
VFA and go through the same process.  Save that curve as well (the
idea is you only do a paper curve once - no more test prints after
that).  Now you can print the image on either paper simply by
activating the appropriate curve.  Sometimes with certain papers a
print is so close to the proof you won't bother making a curve for it,
or maybe it needs a curve with just a very tiny change (often happens
on papers such as PR, Dourian and VFA which are close in contrast and
density to EEM).


 
>My Aurora print is only a tad less saturated than the EEM proof.
>Other than that I don't see much difference. 

However you define the difference is up to you.  That's where each
photographer's unique artistry enters the mix.  The idea is that with
the proof you have established how you want the prints to look.  The
proof is king.  If the Aurora print doesn't look the way you want then
you do the above procedure and make it match the proof as best you
can.  The proof is the standard which final prints should match, no
matter what the paper.  In reality, the various other paper attributes
affect how a print looks and it may not be possible to get an exact
match.  You can set your own tolerances for what degree of difference
is acceptable.

 
>Maybe the EEM is a bit cooler, too?

That's another matter, and with the 2400 (I think you said you use
one) the tone can be adjusted with the ABW controls.  The purpose of
the proof is to establish the contrast and density.  You may choose a
particular paper for the final print for many different reasons (ink
or paper color, texture, brightness, OBAs, etc).  


This stuff always sounds more complicated when you write about it.  In
practice it's pretty simple and intuitive.  Hope this helps.


Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm