Colourspaces in D-cinema, ACES, and streaming

Why are there so many colourspaces in digital cinema/UHD/HDR/WCG/streaming pipelines?

∎ Colourspaces for cameras & VFX/CGI

∎ Colourspaces for grading

∎ Colourspaces for distribution

∎ Colourspaces for presentation/display

In this masterclass, we’ll explore the theoretical and practical aspects of colourspaces commonly used in production, post-production, and presentation of movies, broadcast, streaming video, and games. You’ll learn why the requirements at each stage are distinct, and you’ll gain an understanding of the transforms among them. By the end of the day, you’ll have a deep understanding of power function (“gamma”) and logarithmic/quasilog (“log”) encoding. You’ll learn about the OpenEXR, CTL, ACES, and OpenColorIO approaches to transforms among these colourspaces. You’ll understand the implications of sRGB, 2.2, 2.4, and 2.6-gamma for SDR display, and the HDR10, PQ, and HLG standards for HDR. You’ll appreciate why video in distribution is always display-referred (despite some proponents claiming that their distribution encoding is scene-referred).

Lots of graphs and equations will be shown and explained. If you have first-year university math: great! You'll gain a deep understanding of log coding and the CIE chromaticity diagram, among other things. However, we'll address the necessary math fundamentals during the day; if you have high-school math, you'll come away with a good understanding of colourspaces.

The masterclass is appropriate for:

• DoPs, DITs

• colourists & color assistants

• studio colour scientists

• VFX supervisors, color pipeline TDs

• post-production supervisors

• lighters, shaders, look developers

• data management technicians, media engineers, and mastering engineers

• display calibration engineers

• graphics software developers

Charles Poynton, PhD, is an independent researcher working on image and colour science in Toronto, Canada. He specializes in the physics, mathematics, engineering, and algorithms of digital colour imaging systems, particularly d-cinema and HDR/WCG. ∎