[argyllcms] Re: Argyll + Firefox

  • From: Michel Joly de Lotbinière <michel@xxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sat, 12 Jun 2010 17:02:40 -0400

I'm now feeling quite stupid: I assumed that the Argyll XYZLUT display
profile with color-shifted matrix part would show some kind of obvious
colour distortion when the client software CMM used the matrix part
rather than the normal LUT part.

Howver, both Firefox 3.5.9 and 3.6.3 (with the CMM active for all
image data with or without embedded profiles) using that kind of
Argyll display profile displayed JPEGs with normal colours, including
ordinary JPEGs, as well as special colour-shift test images with
corresponding special embedded profiles, as can be found on
http://foto.beitinger.de/browser_farbmanagement/farb-testbilder.html
and those with v2 embedded profiles on
http://color.org/version4html.xalter

As Marti Maria says, those same browsers indisputably show "matrix
only, discard the LUT" behaviour with his specially prepared image +
profile.

Why is the use of the Argyll XYZLUT profiles with colour-shifting
matrix parts then not showing the shift in Firefox, if Firefox is only
using the matrix parts of the profile?

If the Firefox CMM were silently rejecting the entire Argyll display
profile and reverting to non-CMM display, then the image at the top of
the foto.beitinger.de page would be displayed with RGB shifted to
BRG--but it displays normal colours in Firefox using the Argyll
display profile with the shifted matrix part.

The Windows 7 "Photo Viewer" application uses only the matrix part and
shows RGB shifted to GRB, while the Windows 7 file manager
("Explorer") uses the LUT part to colour manage its JPEG previews, so
those are shown with correct colours, as do other applications that
invoke/use the Windows CMM. (Only Microsoft, with its vast software
development resources, is able to achieve such counter-intuitive
results between its own photo preview application, previews in its
file browser, and other applications using the Windows CMM. Bravo
Microsoft!)

Does anyone have ideas on what's happening here? What am I doing (or
thinking) wrong?

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