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Title: Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area

Abstract

Though sometimes referred to as a two-measure system for evaluating color rendition, IES TM-30-15 includes other key components that go beyond the high-level average values IES Rf and IES Rg. This article focuses on the Color Vector Graphic and Local Chroma Shift (IES Rcs,hj), discussing the calculation methods for these evaluation tools and providing context for the interpretation of the values. It also presents alternatives for quantifying the same characteristics, which can inform the development of future measures. The Color Vector Graphic (CVG) is a visual representation of hue and chroma shifts across different hues. It quickly communicates complex information about how object colors will be rendered by a light source, although it is difficult or impossible to use for writing a specification. CVGs demonstrate that increases in chroma for certain hues sometimes means a decrease in chroma for other hues, and illustrates hue shifts for intermediate colors. The combination of shifts over different hues can be referred to as gamut shape. Complementing this information are the IES Rcs,hj values, which quantify the average relative chroma shift for samples in each of the 16 hue-angle bins (j) specified in IES TM-30-15. Unlike measures of average color fidelity and gamut area,more » gamut shape and hue-specific chroma shift are new concepts with no directly-comparable historical references. It will be critical to incorporate the Color Vector Graphic and Local Chroma Shift values into practice because they capture information about color rendition that is impossible to describe with average measures (such as CIE Ra, IES Rf, or IES Rg), but that is critical to understanding human evaluations of color quality in architectural environments.« less

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]
  1. Pacific Northwest National Laboratory, Portland, Oregon, USA
  2. Department of Architectural Engineering, The Pennsylvania State University, University Park, Pennsylvania, USA
  3. Soraa, Inc., Fremont, California, USA
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1440616
Report Number(s):
PNNL-SA-127109
Journal ID: ISSN 1550-2724; BT0301000
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: LEUKOS; Journal Volume: 14; Journal Issue: 3
Country of Publication:
United States
Language:
English
Subject:
Color Rendition; IES TM-30-15; Chroma Shift; Gamut Shape

Citation Formats

Royer, Michael P., Houser, Kevin W., and David, Aurélien. Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area. United States: N. p., 2017. Web. doi:10.1080/15502724.2017.1372203.
Royer, Michael P., Houser, Kevin W., & David, Aurélien. Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area. United States. doi:10.1080/15502724.2017.1372203.
Royer, Michael P., Houser, Kevin W., and David, Aurélien. Fri . "Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area". United States. doi:10.1080/15502724.2017.1372203.
@article{osti_1440616,
title = {Chroma Shift and Gamut Shape: Going Beyond Average Color Fidelity and Gamut Area},
author = {Royer, Michael P. and Houser, Kevin W. and David, Aurélien},
abstractNote = {Though sometimes referred to as a two-measure system for evaluating color rendition, IES TM-30-15 includes other key components that go beyond the high-level average values IES Rf and IES Rg. This article focuses on the Color Vector Graphic and Local Chroma Shift (IES Rcs,hj), discussing the calculation methods for these evaluation tools and providing context for the interpretation of the values. It also presents alternatives for quantifying the same characteristics, which can inform the development of future measures. The Color Vector Graphic (CVG) is a visual representation of hue and chroma shifts across different hues. It quickly communicates complex information about how object colors will be rendered by a light source, although it is difficult or impossible to use for writing a specification. CVGs demonstrate that increases in chroma for certain hues sometimes means a decrease in chroma for other hues, and illustrates hue shifts for intermediate colors. The combination of shifts over different hues can be referred to as gamut shape. Complementing this information are the IES Rcs,hj values, which quantify the average relative chroma shift for samples in each of the 16 hue-angle bins (j) specified in IES TM-30-15. Unlike measures of average color fidelity and gamut area, gamut shape and hue-specific chroma shift are new concepts with no directly-comparable historical references. It will be critical to incorporate the Color Vector Graphic and Local Chroma Shift values into practice because they capture information about color rendition that is impossible to describe with average measures (such as CIE Ra, IES Rf, or IES Rg), but that is critical to understanding human evaluations of color quality in architectural environments.},
doi = {10.1080/15502724.2017.1372203},
journal = {LEUKOS},
number = 3,
volume = 14,
place = {United States},
year = {Fri Oct 13 00:00:00 EDT 2017},
month = {Fri Oct 13 00:00:00 EDT 2017}
}