Re: [DCP-o-matic] XYZ image sequence colour problems

From all the tests I did so far, ‚white‘ or greys should never come out with a greenish tint, but should stay perceptually white, with a slight shift towards blue after conversion from rec709 or sRGB to XYZ, when analyzed as RGB again in an image editor. The XYZ-TIFF the post house provided clearly shows too much green component (again, when analyzed as RGB). When I convert to XYZ from a proper rec709 or sRGB source, the clock white shows the blueish shift in an RGB display as expected. Most colors are off in XYZ uncorrected, but white and grays stay neutral-blueish. Many people talk about greenish tint when watching DCPs uncorrected, but that is not for whites, but e.g. skin tones. http://www.knuterikevensen.com/?p=1117 Now, neither white point nor gamma are formal aspects of a source, but are ‚baked in‘ to the file, the actual data. That’s why we need calibrated systems. If you tell someone to create a DCDM XYZ Tiff, he needs to know, or to assume, what the original source color space or gamma actually is. If they supply a rec709 source, they can assume color space and gamma. But it is not guaranteed to follow rec709 specs if the film makers did not use calibrated equipment (or equipment that is ‚close to spec‘ incidentally). However, since the film makers are able to supply a reference rec709 oder sRGB clip with ‚their‘ white, I would assume they supplied proper footage to the post house, and that somehow they screwed it. - Carsten