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The Last Frontier on ICC Profiles

A slice of the YCbCr profile when Y=0.5.

Image is Simon A. Eugster, Public domain, via Wikimedia Commons.


Colour management is a key component of imaging applications. Generally speaking, it consists of tools to unambiguously reproduce and transform colour image data between input devices, storage facilities, and output devices. The data is usually (though not always) described as coordinates in a given colour space. ICC profiles specify how to transform them between a source colour space (for instance, one describing your camera’s colour range), and a common, special destination space called the profile connection space.

This talk was about what may be the most special space of all– YCbCr. A staple of analog and digital broadcasting, YCbCr is defined in three distinct International Telecommunications Union recommendations (ITU-R): BT.601-7, BT.709-6, and BT.2020-2. Colour management systems such as Little CMS have long supported it, though it may well be the only colour space that cannot be tested properly. This is because there are no ICC profiles in the wild that target it; except for two such copyrighted specimens, scraped a long time ago from Sun machines, and lost to the mists of time.

The talk covers: the essentials of colour management; the standards describing YCbCr colour space; and how to go from standards to an ICC profile implementing such a transformation.


This project was integrated in Krita in MR !1330. The profile generation code is available on GitHub.

Media coverage

This is the official C3VOC recording of the talk. The slides and the official synopsis are available here. Source code for the slides is available on GitHub.


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  3. Gonzalez, Rafael C., and Richard E. Woods. 2018. Digital Image Processing. 4th ed. Harlow, Essex, UK: Pearson Education.
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  5. ———. 2021. “What Makes SRGB a Special Color Space?” PhotoSauce Blog, May.
  6. ———. 2018. “Making a Minimal SRGB ICC Profile Part 2: Curve the Curves.” PhotoSauce Blog, March.
  7. ———. 2018. “Making a Minimal SRGB ICC Profile Part 3: Choose Your Colors Carefully.” PhotoSauce Blog, April.
  8. Kolås, Øyvind. 2018. “SRGBz—a Minimal SRGB ICC v2 Profile.”
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  10. Poynton, Charles. 2012. Digital Video and HD: Algorithms and Interfaces. 2nd ed. Morgan Kaufmann.
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  12. Stone, Elle. 2013. “In Quest of Well Behaved Working Spaces.” Nine Degrees Photography, September.
  13. ———. 2013. “What Makes a Color Space Well Behaved?” Nine Degrees Photography, September.
  14. ———. 2013. “Are Your Working Space Profiles Well Behaved?” Nine Degrees Photography, September.
  15. ———. 2013. “Elle Stone’s Well-Behaved ICC Profiles and Code.” Nine Degrees Photography.
  16. Tooms, Michael S. 2016. Colour Reproduction in Electronic Imaging Systems. 1st ed. John Wiley & Sons.
  17. International Color Consortium. 2010. “Specification ICC.1:2010 (Profile Version”
  18. International Telecommunications Union. 2011. “Studio Encoding Parameters of Digital Television for Standard 4:3 and Wide-Screen 16:9 Aspect Ratios.”
  19. ———. 2011. “Reference Electro-Optical Transfer Function for Flat Panel Displays Used in HDTV Studio Production.”
  20. ———. 2015. “Parameter Values for the HDTV Standards for Production and International Programme Exchange.”