Re(8): embedded profiles in PDF/Postscript
Re(8): embedded profiles in PDF/Postscript
- Subject: Re(8): embedded profiles in PDF/Postscript
- From: Olaf Drümmer <email@hidden>
- Date: Sun, 6 Jun 2004 17:56:39 +0200
Roger,
here is an excerpt from the PDF 1.5 spec wrt CalRGB (see page 218):
"TABLE 4.14 Entries in a CalRGB color space dictionary
WhitePoint array
(Required) An array of three numbers [XW YW ZW] specifying the
tristimulus value,
in the CIE 1931 XYZ space, of the diffuse white point; see below for
further discussion.
The numbers XW and ZW must be positive, and YW must be equal to 1.0.
BlackPoint array
(Optional) An array of three numbers [XB YB ZB] specifying the
tristimulus value, in
the CIE 1931 XYZ space, of the diffuse black point; see below for further
discussion.
All three of these numbers must be nonnegative. Default value: [0.0 0.0 0.0].
Gamma array
(Optional) An array of three numbers [GR GG GB] specifying the gamma for
the red,
green, and blue (A, B, and C) components of the color space. Default value:
[1.0 1.0 1.0].
Matrix array
(Optional) An array of nine numbers [XA YA ZA XB YB ZB XC YC ZC] specifying
the linear interpretation of the decoded A, B, and C components of the
color space
with respect to the final XYZ representation. Default value: the identity
matrix
[1 0 0 0 1 0 0 0 1]."
A CalRGB color space could be converted to an ICC RGB mntr profile I'd
say though I do not know of any tool that does so. The CalRGB mechanics
are based on the CIEBasedABC color space in PostScript Level 2 and
upwards, though in PostScript you can have more transforms than just one
set of transfer curves and one matrix.
Olaf
email@hidden wrote Sun, 6 Jun 2004 11:09:24 -0400
>
> Think of it as a poor man's (and limited) colorimetric characterization
>
> of grayscale and RGB color.
>
>
Do these profiles exist anywhere in an 'ICC' format? Or will I have to
>
extract them out of an existing PDF file to open them up wih ColorSync
>
Utility? I'm curious to see what I will find out, because I've not seen them
>
documented in the official Adobe PDF 1.5 Specifications anywhere. They are
>
mentioned in the specs but not defined.
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