Am 22.05.05, 21:47 +0200 schrieb Gerhard Fuernkranz: > Kai-Uwe Behrmann schrieb: > white is encoded as 685 (not 255), and black as 95 (as you say). However,
Yes you are right here as well as Bob with 685 not 255. > these values seem to be only the default values, and my interpretation is, > that the defaults may be replaced by individual values, if a different white > or black point is more approrpiate for rendering a particular Cineon image to > an output-referred color space. > > This web page also specifies, how the 10-bit Cineon encoding should be > converted to 8-bit video RGB encoding, and they specify conversion variants > without and with different amounts of soft clipping. The described conversion > can be IMO easily carried out with TRCs. No problem to create the curves and the usual RGB clipping casts too. Soft clipping does not help. > But I'm still wondering, which RGB color space they mean with "video RGB". It > looks like they assume an RGB color space with (default) gamma 1.7, but they > are not perfectly clear about this issue either, since they also seem to call > this "linear RGB"? And so far, I could not find a statement, where they would > specify any RGB primaries of this video RGB color space. CCIR 709 primaries are used. > Furthermore, the colorimetric properties of the Cineon color space itself are > IMO not specified clearly either. The 10-bit log encoding seem to be specified > in terms of "printing densities", where "Printing Density = the density above > D-min of the negative as seen by the combination of print film and the > illumination of a standard motion picture printer" (according to > http://www.kodak.com/US/plugins/acrobat/en/motion/support/dlad/kodak_digital_lad_users_guide.pdf). > But which spectral properties do the assumed film and the "illumination of a > standard motion picture printer" have? A densitometric match does not > necessarily imply a colorimetric match, the same densities may result in > different observed XYZ colors for different films. A dim sorounding is assumed , like usual in TV environments. I think with D65 but not shure. > Regards, > Gerhard > > regards Kai-Uwe Behrmann + development for color management + imaging / panoramas + email: [EMAIL PROTECTED] + http://www.behrmann.name ------------------------------------------------------- This SF.Net email is sponsored by Oracle Space Sweepstakes Want to be the first software developer in space? Enter now for the Oracle Space Sweepstakes! http://ads.osdn.com/?ad_id=7412&alloc_id=16344&op=click _______________________________________________ Lcms-user mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lcms-user
