Color captivates me because it defines so much of our visual experience, while being devilishly difficult to truly comprehend. A light source may cause colors to look natural, distorted, saturated, or muted. Or, more subtly, red objects may be saturated while green objects are muted, or red objects may be hue-shifted toward orange while green-objects are hue-shifted toward blue, or any number of other possible effects. The understanding and characterization of these color-rendition outcomes—that is, changes in hue and saturation caused by light—are the central themes of this LEUKOS Special Issue on Color Rendition.
Some of the topics covered in this special issue include preferred color rendition of skin under various LED sources, tradeoffs between color rendition and luminous efficacy of radiation, essential characteristics of test color samples for color rendering measures, and a new concept of color fidelity based on the lighting of the frescos in the Sistine Chapel. Several papers comment on the need for new and better measures of color rendition.
As this issue was going to press, IES published TM-30-15 IES Method for Evaluating Light Source Color Rendition. TM-30-15 addresses some of the core issues addressed in this special issue. The IES method includes an index to assess color fidelity that is more accurate that the CIE color rendering index, an index to assess the relative gamut (that is, average increase or decrease in saturation), and graphics that visually portray changes in hue and saturation. There has been much anticipation for a new system for characterizing color rendition, and much hope placed on the new IES method, but we are yet to see how it will be received by industry. This issue’s guest editorial discusses what’s next now that TM-30-15 has been approved, including how the IES method may influence future research about color rendition by providing a framework for hypothesis development.
This issue was prepared with the help of two guest editors, Dr. Michael P. Royer, Lighting Engineer at Pacific Northwest National Laboratory (USA), and Dr. János Schanda, Professor Emeritus of the University of Pannonia (Hungary). They both have my sincere thanks for their enthusiasm from day one, and the good judgement they exhibited throughout the development of this issue.
Prof. Schanda (born May 16, 1932) passed away on March 8, 2015. In one of our last correspondence he indicated that “one should not grumble with 82”, and that it was “better to have the opportunity to see how the 13 grandchildren do.” I’ve admired Prof. Schanda’s technical contributions since I was a graduate student, yet it was only in developing this special issue that I had an opportunity to communicate with him more personally. I learned that beyond being an eminent color scientist, he was generous with his ideas and time, a careful and fair-minded reviewer, and passionate to the end. He will be missed.
