[Openicc] XICC specification draft

[Chris Murphy]

Could someone explain to me how remote display works? Where is the  
rendering and compositing occurring? On server or client?

If it's done on server, you could have rasterizing/compositing  
normalize all content to something like sRGB. Less sophisticated  
requirements simply send those numeric values to display on the  
client. More sophisticated requirements can optionally use display  
compensation by assuming sRGB as source, and actual remote display  
profile as destination.

If it's all done on the remote client, then it would be perfectly  
acceptable to NOT include the entire source ICC profiles for each  
object to be displayed, in the case of output device profiles. Matrix  
based profiles are tiny, so really there is no problem sending those.  
But output device profiles can be large, 3MB for a good quality CMYK  
profile, around 2-2.5MB for an RGB profile. But a lot of the data is  
useless for display purposes. There are potentially six tables in  
such a profile and only one is needed. You could get it down to 1/6th  
(approximately) of that size with no quality decrease. You could  
subsample the profile further, on the server side, 33x33x33 table  
profile could be chopped down to 9x9x9 and still be adequate for most  
soft proofing requirements (fine shadow and highlight detail might be  
compromised for the discriminating user).

And even if they were doing video editing or manipulating large  
images remotely, the source of the slow down over the network  
connection is the quantity of numeric image data, not the profile.  
The profile itself is relatively small. Now the conversion overhead  
becomes an issue with increasing file size, but even that can be  
dealt with by only converting the portion that's going to be shown on  
screen rather than the entire file.


Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
---------------------------------------------------------
Co-author "Real World Color Management, 2nd Ed"
Published by PeachPit Press (ISBN 0-321-26722-2)