RE: The MESS at the PRESS campaign
RE: The MESS at the PRESS campaign
- Subject: RE: The MESS at the PRESS campaign
- From: Henrik Holmegaard <email@hidden>
- Date: Mon, 5 Apr 2004 22:18:38 +0200
"Darrian A. Young" <email@hidden> writes :
>I will continue to go with the "high-end", "dedicated",
>and "optimized" proprietary proofing system to get the same precise,
>consistent results it has been producing for quite some time.
It is not that I am blindly toeing the ECI line for ISO 12647, PDF/X-3
or modular transforms for that matter, but more that the other side of
the discussion is using very big display type for a very weak argument
-:).
As I cannot for the life of me find any technical argument in your
post, let us begin with the abc of color space conversion, as in the
cookbooks and countless past threads. If I am technically wrong, you
will correct me on the technical points, of course.
A rendering intent workflow conventionally begins with the AtoB
transform because photography begins with the AtoB transform.
So in Linocolor / Newcolor we have scnr AtoB and prtr BtoA - AtoB and
mntr BtoA where A is device and B is PCS. Now we have a soft-proof.
Or in Linocolor / Newcolor we have scnr AtoB and prtr BtoA - AtoB and
prt BtoA where A is device and B is PCS. Now we have a proof-print.
There is cross-rendering in the prtr profile as the rendering intent
for the output AtoB - BtoA transform is different from the rendering
intent for the input AtoB - BtoA transform.
(Keep in mind that input and output are terms which are relative to the
PCS and not to the everyday language term for the type of device.)
Class scnr profiles are only required to be AtoB. Class prtr and class
mntr are required to both AtoB and BtoA. This gives us bidirectional
Adobe Working Spaces.
We now have the CIEL*a*b* color capture in Adobe Photoshop and we want
to convert it into an RGB Working Space. So we watch out for the RGB
clipping and convert.
We can now place the RGB image in Adobe InDesign as TIFF or PSD and
control its rendering into the ICC CMYK printer profile for the
intended printing condition.
We can predict how the RGB image will render on the soft-proof and the
proof-print because the ICC CMYK printer profile for the intended
printing condition is bidirectional.
Moving forward from Photoshop 5 which could cross-render with
difficulty to Photoshop 6 which could cross-render correctly the List
has agreed that cross-rendering is good.
With InDesign 3 cross-rendering is carried into PDF such that the CMYK
ICC printer profile targetted by the RGB image is embedded as
OutputIntent.
If the image designer applies the desired sharpening to the RGB image
in Photoshop, the story does not have to be more complicated than the
above.
Because the cross-rendering capability is contained in the PDF/X-3
Specification, it is possible to soft-proof and proof-print in PDF
repurposing applications.
Because all images are RGB they will all be converted using the ink
limit and black replacement defined in the forward transform of the
profile for the printing condition.
And because cross-rendering is supported the backward transform will
remap the color appearance and convert into the ink limit and black
replacement for the proof.
CMYK is a redundant data model / color model in the sense that
different process specific CMYK mixes may be used to create the same
color.
At the abc level this is how it is possible to match color across
printing devices which require different ink limits and black
replacements.
(Darrian_1)
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