Re: Distiller 5 CSA to ICC matrix
Re: Distiller 5 CSA to ICC matrix
- Subject: Re: Distiller 5 CSA to ICC matrix
- From: Henrik Holmegaard <email@hidden>
- Date: Sun, 6 May 2001 16:49:13 +0200
Mauro Boscarol wrote:
Do you mean a Photoshop 6 EPS file distilled by Distiller 5?
Also if you select PostScript Color Management and an ICC printer
profile and rendering intent say in Illustrator 9.
The AtoB1 intent (maybe AtoB0 also, I'm not sure yet) in the ICC
printer profile is converted into a CIEBasedDEFG CSA.
The PDF 1.3 specification doesn't implemented calCMYK / CIEBasedDEFG.
So Distiller 4 can't just leave the object as it is and bring both
object and color space specification into the PDF file. It has to
convert the object, so it converts the object into Lab, creating the
first half of a proofing transform.
Distiller 5 leaves the CMYK object alone and instead converts the
color space specification from CIEBasedDEFG to ICC. This way you have
a way ahead with the document.
i.e., ih the case "TagICC UntagPSCM" ICC is ignored?
Yes, because PostScript doesn't support ICC profiles. Distiller is a
PostScript RIP, it only understands PostScript CSAs.
The weakness in creating PDF from Distiller (all versions) is that
you have to pass through a non-ICC process, and on the back end of
that process you can then tag ICC profiles. But only after you loose
your ICC spaces on the front end of the process.
This is why you need something like GretagMacbeth iQueue to
'normalize' your source color spaces into a single destination color
space. Then build your PDF and tag it with that color space.
A better way to create PDF 1.3 is from InDesign, though there are
still some problems left here.
UntagICC TagPSCM in PS6 = ICCBased
which ICCBased (there isn't a ICC in the Photoshop 6 file)?
PDF 1.3 supports three color space specifications: deviceColor,
CIEBased and ICCBased. When you save out PDF from Photoshop 6, you
create ICCBased. When you save out EPS from Photoshop 6, you are
allowed to embed both the whole ICC profile and a CSA built from that
ICC profile. This can cause problems.
--
Henrik Holmegaard
TechWrite, Denmark