[photo-3d] RGB Anaglyphs to CMYK Anaglyphs

[boris@xxxxxxxxxxxx]

>   Date: Sat, 10 Jun 2000 06:11:42 -0700 (PDT)
>   From: Stephen Rumbaugh <gandamill@xxxxxxxxxxxxx>
...
>Does anyone know how to convert an RGB anaglyph to CMYK without destroying
>the blue? If not, does anyone have an ideas where I should turn for help?
>Thanks!

Stephen, if you are preparing for an offset press job, you should have your
printer do the CMYK conversion/separation using RGB files you supply on
disk.  That's because he will know what dot gain and other press factors to
incorporate into the CMYK conversion.  The printer should use your RGB
inkjet output (assuming it is to your satisfaction) as a guide and proof
for the conversion.  He should then do a chromalin, and you should proof
that chromalin for the 3-d effect and ghosting.

When I did the OVERDRIVE job last year, the magazine people used photoshop
for CMYK conversion.  They did all their pre-press in house, as they have a
close working relationship with the printer.  Trouble was that my
experience with using Photoshop to do the CMYK conversion has not been
good.  (But then I am not an expert with Photoshop, at least not with CMYK
pre-press type work.)  They did the first conversions from my RGB files,
and thank god I got to see a chromalin, because it was terrible!

My own experience, limited though it is, has shown fairly good results when
I do CMYK conversions using software called Live Picture.  I ended up doing
the pre-press for the anaglyph images in OVERDRIVE magazine, and they ran
negs straight off my CMYK files.

Unfortunately LP is defunct, my copy is v.2.1 from about 1995. I'm not sure
where you can get an older copy of it.  Mine runs on a mac.  LP keeps the
colors very pure, especially important on the blue side, to avoid ghosting
in the right eye.  Where Photoshop might put in a mix of Cyan and yellow or
magenta, LP will just do a high density Cyan.  I understand the math of
color conversions very little, and it has always been a mystery why one
software would work differently from another.  But for anaglyphs Live
Picture has been very good.

Boris


- Science is the part of culture that rubs against the world.
-
-                                     Stanislaw Lem, _His Master's Voice_

Boris Starosta                        boris@xxxxxxxxxxxx
Stereoscopic Art & 3-D Photography    http://www.starosta.com
usa - 804 979 3930                    http://www.starosta.com/3dshowcase



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