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Digital BW, The Print

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Quadtone separation profiles

2001-08-29 by Dan Culbertson

I *think* I have a solution on how to make RGB profiles that do both
softproofing *and* separation.  I noticed that the Epson Standard profile
that comes with Mac drivers is really an artificial RGB space very similar
to ColorMatch RGB - except, unlike ColorMatch RGB, it is a *printer* profile
and shows up in Doctor Pro.  This leads me to believe that it could be used
as a "do nothing" profile for any 1.8 gamma grayscale file -- meaning it
only changes the file to RGB.  However, if that profile is run through
Doctor Pro with a standard RGB channel separation method it could be used to
automatically convert to RGB and separate the channels on the way to the
driver.  Haven't figured out yet how to blend the softproof portion of one
profile with the separate channels portion of another so this is still a two
profile technique (one to separate and one to preview).  For CMYK quadtone
methods Photoshop 5 allowed a "from CMYK" table (preview)  from one profile
to be merged with a "to CMYK" table (separation) but that doesn't work for
RGB profiles and it never quite did the same thing as a good CMYK manual
separation.  So I'm still not quite at quadtone profile Nirvanna.  But I
think I am one step closer.  Any suggestions on merging the from/to pieces
of two RGB profiles would be appreciated.  Nirvana would be a single profile
that RGB previews (with View/Proof Setup from a Profiler Pro RGB profile)
while still in grayscale then converts to RGB and separates channels
correctly in the printer space dialog dropdown box.  Of course if you need
to tweak RGB curves to change tints (for tinted inks) it would still be
necessary to convert to RGB first (or make alternate separation profiles for
each tint you normally prefer).  Anyhow -  stay tuned.  Danitism isn't a
static target -- with enough Absolut anything is possible.

Dan Culbertson

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