Color Theory in HDR and Wide Color Gamut at SMPTE 2017 conference

[DCI forum]

https://www.youtube.com/watch?v=Z0DS7cnAYPk

Abstract:
As is well-known, colors as they exist in the real world must be adjusted so as to look correct and pleasing when displayed on a television or cinema screen. In color science, the process of converting these “scene-referred” colors to “display-referred” colors is termed “rendering.” The Academy's ACES system is a good example of a set of open-source picture rendering algorithms. In this paper the authors, who both participated in the development of ACES, discuss the pros and cons of various rendering techniques and share the results of their latest work. Specifically we present a method of applying a tone curve that preserves color ratios and has better noise properties than earlier techniques. This algorithm has been successfully used as part of a larger parametric rendering system for HDR display. One of the nice properties of this algorithm is that it has a simple and robust inverse.
Published in: SMPTE 2017 Annual Technical Conference and Exhibition

[DCI forum]

https://www.youtube.com/watch?v=cuWUvCr40GA

ΔE00 no longer matches human perception in HDR and Wide Color Gamut imagery, so use ΔICTCP instead for these smaller differences in perception.


Abstract:
With the emerging demand for high-dynamic-range (HDR) and wide-color-gamut (WCG) technologies, display and projector manufacturers are racing to extend their color primaries in the cinema and in the home. With these brighter and wider colors, the question is: in calibration, how close is close enough? This answer is increasingly important for both the consumer and professional display/projector market as they balance design trade-offs. With HDR/WCG technology, an increasing issue is that many of the color difference metrics in common use today, such as ΔE00, substantially deviate from human perception and become unreliable for measuring color differences. This causes under and over prediction of color differences and can to lead to sub-optimal design decisions and difficulties during calibration. There is a large amount of perceptual color difference data in the field today, however the majority was collected using reflective surfaces and very little reaches the boundaries of modern display capabilities. To provide a better tool for facilitating design choices, this paper will present a “ground truth” visible color difference dataset. These visual experiments were conducted between luminance levels of 0.1 and 1000 cd/m2 on high dynamic range laser cinema projectors with approximate BT.2100 color primaries. We will present our findings, compare against current metrics, and propose specifying color tolerances using the ΔICTCP metric for HDR and WCG imagery.

Published in: SMPTE 2017 Annual Technical Conference and Exhibition