On Sun, 22 May 2005, Gerhard Fuernkranz wrote:
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.
The problem is that Cineon log is really just an encoding and does not have a well defined color space. The "color space" is primarily determined by the film type which is scanned, and whether it is a negative or print. Kodak publishes default values for each film type that they sell. The most scientific description I have found for film is available at "http://wwwau.kodak.com/US/en/motion/support/h1/structureP.shtml";. There is also useful information in the document at "http://www.filmlight.ltd.uk/documents/FL-TN-00-002.pdf";.
Note that regardless of whether the film is mounted in your 35mm SLR or part of a movie reel, the film is comprised of the same basic stuff so there is likely general value for understanding its behavior.
Even though digital cameras are currently the rage, a traditional film camera coupled with a high-quality negative scanner should be able to produce images with much better dynamic range.
Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ ------------------------------------------------------- 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
