[Openicc] LGM2010 colour management BoF

[Kai-Uwe Behrmann]

Hello dear participants,

here come the notes of our BoF session on friday in de pianofabriek 
metting room. Nicolas and me have snapped as good as we could.

kind regards
Kai-Uwe Behrmann
-- 
developing for colour management 
www.behrmann.name + www.oyranos.org

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OpenICC colour managment BoF at LGM 2010 29th may


Participants:
Pascal de Bruijn [p] - libre softeware enthusiast
Kai-Uwe Behrmann [kub] - Oyranos project
Yiannis Belias - Oyranos project
Ginger Coons [gc] - Open Color Specification
Jean Gali - Scribus
Peter Linnell [pl] - Scribus
Leonard Rosenthol [lr] - Adobe
Chris Lilley [cl] - W3C
Hin-Tak Leung - Ghostscript
Nicolas Maleve (notes) - constant
Boudewijn Rempt [b] - Krita
Alexandre Prokoudine - tech writer

List of items by kub + one add from gc


ICC Profile in X
The spec started around four years ago. It is designed to 
work with the Xorg server. X colour server needs to better specify the 
meaning of the ICC Profile in X.
Attendences voted for keeping backward compatibility and accept the
concretisation. The _ICC_PROFILE(_xxx) will be modified at start of 
a X colour server and place a sRGB dummy therein. sRGB is considered the 
default desktop entrance colour space.

cl: Does this support soft-proofing?
kub: Root window has one color profile per device. Thats too few 
information for proofing. Proofing is typical a application specific 
feature not a desktop one.

You need to test another profile for a second or more monitor(s).

lr: Why cant you put color management at the bottom of everything, like 
macos + microsoft do?
kub: It may be too much work. You have to take care of all libraries. You 
can't control the entire software stack, like apple + microsoft do. It may 
be something that X doesn't make easy? It's not as monolithic as apple +
microsoft. Kub not really a X insider to suggest now something.


Color management in video + color management elsewhere -- is it related or
not?
lr: Any random video will most likely be srgb, but the industry is going 
in another direction -- hdtv, etc. A new generation of icc profiles is 
planned to deal with this.


Modifying icc profiles through adding device + driver informations.
lr: By modifying the binary info of the profile, you change the md5 hash. 
PDF's can point to color profiles referenced by md5 hash. If you're going 
to start modifying known identities, a lot of things will break.
You have to take care that the user knows this, e.g. by doing the 
modification explicitely only.

Q: Can we rely on the data inside the profiles for the future? No, the icc
hasn't specified what goes into what tag. It will need some time to settle 
with properties for the meta tag.

One problem of the icc is cmm's reading tags in a custom way.


HDR rendering description
cl: HDR may not fit into a icc profile. Scene versus output refered 
values.
kub: need add both to a named colour description


Swatch books
kub: CGATS (safe place to exchange spectral data)
lr: CxF is the direction of the industry.
pl: How open is CxF?
lr: The spec is an ISO standard. Seems not to have probs with
patents. Implementing it may be a problem. Ascii is no problem but the xml 
(the direction of industry). The schema is patented by the xrite 
corporation.
cl: There's technology to work around this.
lr: No, it doesn't work. Everyone is pushing to get this license changed.
cl: Your argument: "You are using this thing that works, but the industry 
is moving in a direction that doesn't work".

http://www.gwg.org/


KDE + Gnome colour management collaboration
would a C interface be of interest for connecting to Oyranos?
p: GCM uses DBus
pl: DBus is ok with Scribus
b: possibly Krita can use too
kub: wants to look at DBus for Oyranos


Html5 and ICC --> important point
canvas works: this is a rectangle on the screen, make calls to it. The 
html5 working group would be open to suggestions. Apple may be making 
them. Safari is color-managed.
Firefox has deteriorated in color support.
Opera has no color management. IE will include it. Chrome doesnt.
There is a new spec: svg color.
The first thing is embedded images (1. get flickr images to display 
correctly  2. allow designers to trust their choice of colors).


If cairo does color management, that could help a lot of projects.
No one developing cairo is present.


Physical representation of color (gc)
gc: Color management for designers.
A physical color spec, a print spec, color-management across media. only
pantone is doing it.
You need a cooperation of a lot of people.
If two designers cant decide on a color without meeting, it's data loss.
Hair color spec.

pl: An open swatchbook.