[Openexr-devel] recent back-and-forth re: Florian's proposal vs. using ICC profiles

[Joseph Goldstone]

I am an ICC member delegate, and a member of the newly-formed ICC 
Digital Cinema Working Group, and would like to say a few things (in 
response to a request by Florian) __on_my_own__, not pretending to 
represent the ICC in any __official__, __sanctioned__ way.

Just so that's clear.  Now:

(a) Florian's proposal is a scene-referred encoding and although the 
flexibility to support scene-referred encodings in ICC profiles may be 
there, it's not the path that is as well trod as that of 
output-referred encodings.  The ICC needs to write this up, in my 
humble opinion.

(b) to the list of reasons why some have had difficulty with ICC 
profiles in a cinema workflow that Chris put out there (lack of 
knowledge of ICC spec, of math, of color, or of the human visual 
system) I would add that until recently there has not been a publicly 
available, open-source library for reading and writing ICC profiles -- 
at least not one that was independent of a particular open-source CMS.  
This has changed.

(c) the ICC was actively reviewing what, if anything, might be needed 
to support color management for high-accuracy projected imagery coming 
from a combination of image states (input-referred, output-referred, 
scene-referred) even before the OpenEXR color management proposal was 
out there.

(d) the OpenEXR color management proposal is being looked at very 
closely by members of the Digital Cinema working group (of which I am 
vice-chair).

(e) that said, the ICC is not an organization that pays its members - 
they are in many cases volunteers, and have substantial primary work 
commitments.  The OpenEXR color management proposal is on a fast track, 
is funded and staffed, and is solving a very specific need.  Florian is 
working very hard, with the full support of his management, on this, at 
a pace the ICC might be hard-pressed to match.

(f) The OpenEXR audience is relatively small compared to that for ICC 
profiles.  As a consequence, and with all due respect, it may not be as 
important for OpenEXR that its proposed color management scheme work 
right the first time; witness the way support for image tiling went 
into OpenEXR.  To be completely frank, I'd be happy if anything ideas 
might go into a future ICC revision to support this community's needs 
be field-tested by means that didn't affect mainline ICC profile users.

I understand how people like Kevin and Ken have a real, pressing, 
day-to-day need for image exchange with transportable color.  And as 
Chris points out, this is what the ICC has been all about since day 
one.

How many of the other developers on this list need consistent, 
transportable color RIGHT NOW?  This is not a rhetorical question, I'm 
sincerely putting it out there to the group.  What's the timeframe in 
which your application really NEEDS to have this solved?  Next month?  
Six months out?  A year out?

I want to second the note in the mail from Chris suggesting people go 
to Scottsdale in November for the Color Imaging Conference.  It's an 
opportunity to talk with the people who write what's in the books that 
are on all of our shelves: Hunt, Fairchild, Poynton, Luo, Green, 
MacDonald, Hardeberg, Moravic, Ishii... and I would expect a couple 
dozen ICC members, almost certainly including nearly all the Digital 
Cinema working group members.  That URL again is:
        http://www.imaging.org/conferences/cic12/

Finally, I wasn't kidding about that being a non-rhetorical question 
above.  I'd really like to know who besides Kevin and Ken are really 
squeezed right now for an OpenEXR color management solution, because it 
would let me take back to the ICC DC WG some sense of the criticality 
of this issue.

Thanks.

[again, all opinions here are my own and do not reflect any official 
position of the ICC]