Criteria for the evaluation of extended-gamut colour encodings

CIE 168:2005
Division 8
978 3 901906 42 8

The CIE TC 8-05 terms of reference include defining a "minimal set of standard colour spaces that addresses a wide range of imaging applications". One set of applications that was identified by the committee required the use of extended-gamut colour encodings. This document defines a set of objective metrics for evaluating the characteristics of output-referred extended-gamut colour encodings. Detailed metrics have been developed to evaluate a number of important attributes of extended-gamut colour encodings. These criteria include:

  • gamut volume characteristics,
  • colour quantization characteristics,
  • hue constancy when applying non-linear tone scale modifications to RGB colour values,
  • complexity of transformation required to and from typical standard spaces (sRGB, ICC PCS, etc.).

The relative importance of the individual metrics will vary on an application-by-application basis. As a result, the committee concluded that the actual evaluation of candidate colour encodings for use in particular applications should be left to other standards bodies that are more closely aligned with the relevant industry segments, and therefore would be better able to define the appropriate application-dependent requirements.

The report is written in English, with a short summary in French and German. It consists of 68 pages with 61 figures and 18 tables.

The following members of CIE 8-05 "Communication of Colour Information" took part in the preparation of this Technical Report :

  • R. Bala, USA
  • R. Buckley, USA (Chair from 2000)
  • M. Gorzynski, USA
  • H. Ikegami, Japan
  • N. Katoh, Japan
  • S. Livens, Belgium
  • L. MacDonald, Great Britain (Chair till 2000)
  • T. Newman, USA
  • M. Pointer, Great Britain
  • K. Spaulding, USA
  • I. Tastl, USA
  • K. Wenzel, Hungary


  • G. Braun (USA)
  • J. King (USA)
  • D. Rich (USA)