Re: CMYK for photographers
Re: CMYK for photographers
- Subject: Re: CMYK for photographers
- From: Chris Murphy <email@hidden>
- Date: Mon, 26 Mar 2012 10:51:42 -0600
On Mar 23, 2012, at 4:32 PM, email@hidden wrote:
>
> So should photographers who choose to convert to CMYK themselves who had
> been using SWOPv2 change to the newer SWOP2006 profiles?
>
>
> Along the same lines, I'm helping a friend setup an Epson 7900 proofing
> edition with EFI XF 4.1. They send untagged PDF/X-1a documents to the RIP
> from indesign CS3. We plan to set up the Epson with GRACoL certification
> and the training videos suggest setting the "CMYK source" in EFI to
> CoatedGRACol2006.icc
a. "untagged" PDF/X-1a doesn't really make sense. It is "tagged" with an OutputIntent, and if it's not a standard condition, then an ICC profile must be embedded, which implicitly acts as both a source and destination profile for all CMYK content.
b. GRACoL is a broad lithographic printing specification. The CoatedGRACoL2006.icc profile (Adobe) is based on a particular data set (CGATS TR 006). It's possible to conform to the printing specification, yet have a printing behavior that is not like that data set.
c. PDF/X-1a dictates that the PDF itself determines the Output Intent. An override at the proofing RIP is kinda sloppy. It departs from a major point of the spec. Prepare the document correctly by having it announce its condition correctly, and have the proofing RIP honor the Output Intent.
d. If the condition is compatible with CoatedGRACoL2006.icc, then the use of SWOP v2 or either SWOP 2006 condition, doesn't seem to be indicated. You don't want your images converted to SWOP (any of them) yet then have InDesign producing PDF/X-1a's set to CoatedGRACoL2006.icc.
>
> Does that mean the PDF/X-1a from indesign (and the included images)
> should also be in the CoatedGRACol2006 space before it is sent to the RIP
> untagged?
The PDF/X-1a's Output Intent should be set to the intended printing condition, yes. All CMYK images placed in the InDesign document should likewise be in that same color space. It is possible to place RGB images into InDesign, and have them converted to CMYK at the time the PDF/X-1a is produced by InDesign (by default it will do this anyway, if you're choosing a PDF/X-1a preset because RGB isn't allowed).
While the CMYK objects in the PDF/X-1a are /DeviceCMYK, i.e. they are not "tagged" or more correctly they are not /ICCBased, the Output Intent which is required by PDF/X-1a, is the implicit source *and* destination profile for CMYK objects in the document.
>
> And a final question, should photographers convert to CoatedGRACoL2006
> instead of SWOPgrade3 for unspecified CMYK conversion or just stick with
> SWOPv2 and pretend none of this happened?
It's like asking me if I should rent a car in Tokyo or New York City when I'm not being told whether I'm going to be in Tokyo or NYC. The answer is, I don't know. If you get it wrong, you're compromising something no matter what.
The safest option is the one with the lowest practical ink limit, not knowing anything else. And for that it's SWOP coated 5, with an ink limit of 300%. Coated 3 limits at around 310%. And GRACoL 2006 Coated 1/2 limits at 320%. If you bust an ink limit, printing companies are well within their right to reject the job.
Chris Murphy
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