RE: ScannerRGB to WorkingSpaceRGB (rendering intents)
RE: ScannerRGB to WorkingSpaceRGB (rendering intents)
- Subject: RE: ScannerRGB to WorkingSpaceRGB (rendering intents)
- From: olaf druemmer <email@hidden>
- Date: Sun, 8 Jul 2001 22:25:50 +0200
More (maybe dumb, sorry) questions:
>
--- Michael Stokes wrote 7/8/01 9:21 PM: ---
>
A. Gamut mapping is an issue in any conversion between any two
>
non-identical color spaces.
>
B. Gamut mapping is composed typically of both gamut compression and
>
gamut expansion (in addition to the usual secret sauce of vendors).
>
C. Gamut compression is only an issue if the destination space is at any
>
point in the 3D volume smaller than the source space.
>
D. The ICC PCS does not contain all colors (easy examples would be
>
fluorescences and large dynamic ranges), but in some implementations it
>
can contain most typical devices on the market today.
(a.) Given how we typically create ICC profiles for a scanner the
following would apply:
Based on a test chart (that usually does not contain fluorescent colors)
some algorithmic strategy is derived how to go from raw RGB numbers
reflecting scanned color patches to 'ideal' numbers reflecting
'objectively' measured Lab/XYZ values of the same patches. Maybe a bit
naively I would assume that all the color patches can be represented
using the color spcae of ICC PCS. (Obviously this assumption lacks
provisions for any extrapolated aspects of that algorithm.)
If this is correct: what does D. mean then for real production life?
If this is wrong: how does a scanner profiling setup deal with 'extreme'
colors? Can a photo have fluorescent colors? Also, what do we gain from
this (I have difficulty understanding how ICC based color management is
going to produce fluorosecent colors at the end of a production chain)?
(b.) Are things different (in real production life, not so much in
theory) with digital cameras?
(c.) Are things different (in real production life, not so much in
theory) with monitors?
Olaf Druemmer
-----------------------------------------------------------------------
Olaf Druemmer
-----------------------------------------------------------------------
callas software gmbh Tel +49.30.44390310 Leonardo +49.30.44342390
Schoenhauser Allee 6-7 Fax +49.30.4416402 connect.pdf +49.30.44342391
D 10119 Berlin email@hidden
http://www.callas.de
-----------------------------------------------------------------------
Now hiring - open positions for C++ developers on Mac, Windows & Linux.
-----------------------------------------------------------------------