Color changing under graphic inclusion with graphicx

[Paulo Ney de Souza]

On Mon, Jan 11, 2021 at 1:14 PM Ulrike Fischer <news3 at nililand.de> wrote:

> Am Sun, 10 Jan 2021 11:20:20 -0800 schrieb Paulo Ney de Souza:
>
> > As Phil has already determined, the problem only occurs in XeTeX (not in
> > pdfTeX or LuaTeX).
>
> Yes, why didn't you mention directly which engine you are using?
>


Because we are only humans Ulrike. Sorry! I know the drill very well, but
it was
an incredibly hard bug to pin down -- and I am not sure we are done. It was
caught in a Production Suite we developed for a publisher, in the final
printing
of a cover for a book, by someone with a very good eye. For many weeks we
(erroneously) treated as some sort of problem  at the printer end (we do
have
a fair share of those) or some bad conversion of the PDF.

There were many levels and a lot of software packages involved (ImageMagic,
GIMP, TeX, LaTeX packages, ICC profiles, Acrobat ... and whatever else the
printers do to it) and finding the colors, producing the images for the MWE
was
incredibly complex. Soo much so that I initially forgot about noting the
pdf,xe,luatex
differences. Phil picked up gracefully and pretty quickly.



> Well the backend of xelatex, dvipdfmx, has quite extended PNG
> support, see the documentation (texdoc dvipdfmx).
>
> And looking at the pdf one can see that your images are included
> with different color spaces. The "wrong" uses CalRGB
>
> <</ColorSpace[/Indexed[/CalRGB<</WhitePoint[.95046 1
> 1.08906]/Gamma[2.19998 2.19998
> 2.19998]/Matrix[.41239 .21264 .01933
> .35758 .71517 .11919 .18048 .07219 .95053]>>]1<504053ffffff>]
>
> The other one DeviceRGB:
>
> <</ColorSpace[/Indexed/DeviceRGB 1<504053ffffff>]
>
> pdftex uses DeviceRGB in both cases.
>
> I have no idea if  this can be configured, you could check the
> documentation or ask on the dvipdfmx mailing list.
>
> --
> Ulrike Fischer
> https://www.troubleshooting-tex.de/



Many thanks will follow up with them.

Paulo Ney
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://tug.org/pipermail/texhax/attachments/20210111/f68c5f2e/attachment.html>