[XeTeX] cmyk encoded files

[Daniel Greenhoe]

2011/11/20 Zdenek Wagner <zdenek.wagner at gmail.com>:
> No.

> LCMS is a good choice.
LCMS is "Little Color Management System"?
(http://www.color.org/opensource.xalter)?

> 1. It ensures that the colours you specify in the document will be converted to cmyk.
> However, the corrections are wrong.
> 2. xcolor does not look into inserted graphics,...

But what if I hand define all my colors using cmyk syntax like this for example
     \definecolor{magenta}{cmyk}{0,1,0,0}
and create all my graphics using pstricks and related packages (with
no inserted graphics)?
Then won't the resulting pdf be cmyk compliant and contain exactly the
colors I defined?

Dan




2011/11/20 Zdenek Wagner <zdenek.wagner at gmail.com>:
> 2011/11/19 Daniel Greenhoe <dgreenhoe at gmail.com>:
>> Print shops often require pdf files containing color to be encoded
>> using CMYK colorspace values.
>>
>> Version 2.11 of the xcolor package says that cmyk is "supported by
>> Postscripts directly" (page 8). So if I simply specify
>>  \usepackage[cmyk]{xcolor}
>> in the preamble and compile with XeTeX/XeLaTeX, is that sufficient to
>> ensure the resulting pdf is cmyk encoded?
>>
> No.
>
> 1. It ensures that the colours you specify in the document will be
> converted to cmyk. However, the corrections are wrong. If you wish to
> convert the colours properly, you have to use colour profiles. LCMS is
> a good choice. Useful ICC profiles come with different products as
> Adobe Reader, colour printers, scanners etc. They can also be
> downloaded from the web. Calculations in the xcolor package can only
> be used if you are satisfied with approximate colours. It is written
> in the documentation that conversions are device dependent.
>
> 2. xcolor does not look into inserted graphics, you have to convert
> your images to cmyk separately. Again LCMS is a good tool for this
> purpose.
>
>> Secondly, is there any free utility available for checking the
>> colorspace encoding of pdf files (maybe similar to foolab's pdffonts
>> for checking embedded fonts).
>>
> I have not found any. Since I produce PDF files for printing very
> often, I calculated that commercial Adobe Acrobat is cheaper than the
> risk of paying unusable books, thus I have bought it.
>
>> Many thanks in advance,
>> Dan
>>
>>
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>
>
>
> --
> Zdeněk Wagner
> http://hroch486.icpf.cas.cz/wagner/
> http://icebearsoft.euweb.cz
>
>
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