[tex-live] ICC profiles for PDF/A compliance

[Peter Selinger]

Mojca Miklavec wrote:
> 
> On Thu, 13 Sep 2018 at 04:32, Peter Selinger wrote:
> >
> > As I understand it, there isn't really any reason to include non-free
> > profiles. It should be possible to just replace the ones we currently
> > have with free ones. -- Peter
> 
> That's approximately like saying that it should be fully sufficient to
> ship just a single font with TeX Live, or to use just a single font in
> every single document.
> Sure, we need a default font, and if all you want to do is to transfer
> some text to another person, you don't really care if it's all done in
> a free version of Comic Sans.
> 
> I'm not an expert here, but if one single profile was all that was
> needed, it wouldn't be required to specify it at all.
> 
> We are talking about having at least one free profile which could be
> used by default, but some additional ones, even if distributed only
> via tlcontrib, would certainly help.

No, it's not analogous. Color profiles are associated to (high-end)
devices like printers, scanners, digital cameras, and monitors. They
are generated by calibrating these devices, and are usually provided
by the device's manufacturer, or in some cases, can be generated by
users using (expensive) calibration hardware and software. If a user
needs to supply their own color profile for inclusion in a PDF file,
they will usually use a (non-free) profile that comes with their
hardware or that they otherwise associate with their image data.  For
example, if I take a picture with a high-end digital camera, the
picture file includes the camera's (non-free) color profile as part of
its meta-data, and if I later use the image in a PDF file, the color
profile makes its way into the PDF. This ensures that the printer
interprets the colors in the way intended by the original device (the
camera).

There is no reason, in my opinion, for TeXLive to become a repository
for a large number of color profiles from different sources,
especially non-free ones.

The only reason a TeX distribution needs to include any profile at all
is that certain PDF standards require the inclusion of a profile,
*even if the document does not contain any color* or *even if the
document only includes vanilla RGB color*. Therefore, the reasonable
thing to do, in my opinion, is to include a single, free, sRGB
profile. It may also be reasonable to additionally include a single,
free CMYK profile (such as FOGRA39, which seems to be an ISO standard
for "typical print made by commercial offset litho") in case there are
any users who use a CMYK image from an unsophisticated source that
does not already have a color profile associated with it.

-- Peter