SMPTE Digital Cinema White Gamut Practices Study Group Report
By using the XYZ color space, the SMPTE Standards and Recommended Practices effectively allow for an infinite range of reproducible whites. The numerical color encoding chosen in the standard constrains the available colors at peak luminance (48 cd/m2) to a still-large set. However, SMPTE does not specify which of these encode-able colors are reproducible in exhibition. This means that colors can be mastered (encoded) that may not be seen by audiences in exhibition. Likewise, colors displayed in exhibition may never have been seen in mastering. For example, if your DI mastering suite were set up in RGB for a D55 white point at 48 cd/m2, projectors in current digital cinema exhibition practice, using the projector configuration file DCDM_XYZ_239, would not accurately reproduce the encoded master at peak white. Further, there is significant confusion between White Point, the color with maximum possible luminance, and Calibration White, a specific color chosen for calibration or verification purposes. — To address these issues a study group was created within the SMPTE 21DC Technology committee. This Study Group was tasked to report on and recommend solutions to these issues noted above. This report will provide definitions of terms that relate to White Gamut, and White Point. It will also report on findings of current practices in both the mastering environment and exhibition community. Finally the report will provide a recommendation for a proposed constrained White Gamut and will seek to point out all relevant SMPTE documents that would need modification to support this proposal. — The SMPTE Digital Cinema White Gamut Study Group began its effort in December of 2006. The report was finished in June of 2008 and the Study Group was tasked to provide a demonstration of its findings and consequences to the general Hollywood SMPTE and ASC community. This task was finally completed on March 24, 2009 at the Linwood Dunn Theatre of the Academy of Motion Picture Arts and Sciences during a joint Hollywood Chapter SMPTE and ASC meeting.
- Print ISSN
- 1545-0279
- Electronic ISSN
- 2160-2492
- Published
- 2009-10
- Content type
- Original Research
- DOI
- 10.5594/J15984