New method for specifying color‐rendering properties of light sources based on feeling of contrast

Hashimoto, Kenjiro; Yano, Tadashi; Shimizu, Masanori; Nayatani, Yoshinobu

doi:10.1002/col.20338

Cited by 136 publications

(75 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the latter case, the aim is not to reproduce colors correctly (as far as the colors are correct when objects are illuminated with the reference source), but to find a light source which yields colors that look 'right' or 'nice'. We agree with several other authors that it is probably impossible to find a single index which describes the color quality of light sources sufficiently accurately, and that several indices will have to supplement each other [29][30][31].…”

Section: Color Rendering (Cri and Cqs)supporting

confidence: 90%

“…One class compares the rendered colors to those of a reference light source (like the CRI and the CQS). Others, like the flattery index [27], preference index [28], FCI (feeling of contrast index) [30] and HRI (color harmony index) [31] try to quantify the naturalness, vividness, color gamut area or harmony between colors. In the latter case, the aim is not to reproduce colors correctly (as far as the colors are correct when objects are illuminated with the reference source), but to find a light source which yields colors that look 'right' or 'nice'.…”

Section: Color Rendering (Cri and Cqs)mentioning

confidence: 99%

See 1 more Smart Citation

Selecting Conversion Phosphors for White Light-Emitting Diodes

Smet

Parmentier

Poelman

2011

J. Electrochem. Soc.

703

501

View full text Add to dashboard Cite

Light emitting diodes (LEDs) are on the verge of a breakthrough in general lighting, due to their rapidly improving efficiency. Currently, white LEDs with high color rendering are mainly based on wavelength conversion by one or more phosphor materials. This Review first describes how to quantify the quality of a light source, discussing the color rendering index (CRI) and alternative color quality indices. Then, six main criteria are identified and discussed, which should be fulfilled by a phosphor candidate to be considered for actual application in LEDs. These criteria deal with the shape and position of the emission and the excitation spectra, the thermal quenching behavior, the quantum efficiency, the chemical and thermal stability and finally with the occurrence of saturation effects. Based on these criteria, the most common dopant ions (broad-band emitting Eu AbstractLight emitting diodes (LEDs) are on the verge of a breakthrough in general lighting, due to their rapidly improving efficiency. Currently, white LEDs with high color rendering are mainly based on wavelength conversion by one or more phosphor materials. This Review first describes how to quantify the quality of a light source, discussing the color rendering index (CRI) and alternative color quality indices. Then, six main criteria are identified and discussed, which should be fulfilled by a phosphor candidate to be considered for actual application in LEDs. These criteria deal with the shape and position of the emission and the excitation spectra, the thermal quenching behavior, the quantum efficiency, the chemical and thermal stability and finally with the occurrence of saturation effects. Based on these criteria, the most common dopant ions (broad-band emitting Eu

show abstract

Section: Color Rendering (Cri and Cqs)supporting

confidence: 90%

Section: Color Rendering (Cri and Cqs)mentioning

confidence: 99%

Selecting Conversion Phosphors for White Light-Emitting Diodes

Smet

Parmentier

Poelman

2011

J. Electrochem. Soc.

703

501

View full text Add to dashboard Cite

show abstract

“…In response to the recognized, inherent limitation of CRI, Judd, one of its developers, proposed “flattery index” as a complementary measure of color rendering to characterize how “vivid” or “flattering” objects, particularly skin, might be rendered by light sources 4. A few years later, Thornton promoted the concept of gamut area as another measure of color rendering, emphasizing “color discrimination.”5 Indeed, many alternative or complementary measures of the color rendering properties of light sources have been proposed since CRI was developed 4–25. Nevertheless, CRI has become the primary measure of light source color rendering by the lighting community 25…”

Section: Introductionmentioning

confidence: 99%

Color rendering: Beyond pride and prejudice

Rea

Freyssinier

2010

Color Research & Application

103

View full text Add to dashboard Cite

It is a truth, universally ignored, that a single metric of color rendering must be in want of another. Evidence presented here, together with those from an earlier study, strongly suggest that the quest for a single metric to quantify color rendering will be in vain. Rather, the strengths of color rendering index (CRI) and of gamut area index (GAI) y seem to counteract the weaknesses of one another, such that together they can be used to guide lighting practitioners in choosing a source that will provide good color rendering of most objects in most applications. The present study was conducted to determine whether sources, both warm and cool, with high levels of both CRI (above 80) and GAI (above 80 and less than 100) were judged better than ones with high levels of just CRI or just GAI. The results support the conclusion that a two-metric system of color rendering is needed for general illumination applications.

show abstract

“…This equation alone is used in the assessment of ''visual clarity.'' 25,26 Formulas for Feeling of Floridness…”

Section: Formulas For Feeling Of Contrastmentioning

confidence: 99%

Proposal for selecting two‐color combinations with various affections. Part I: Introduction of the method

Nayatani¹,

Sakai

2009

Color Research & Application

Self Cite

View full text Add to dashboard Cite

A method is proposed for selecting two-color combinations with various feelings. Feelings used are pleasantness, contrast, floridness, warmth, and their combinations. The proposed method is given by its flow chart for selecting the candidates of two-color combinations adapting to target feeling(s). The effectiveness of the proposed method is shown by the correlation coefficients between observed and predicted values for four kinds of feelings. Munsell H V/Cs of each component color are necessary for prediction; the prediction formulas are given for estimating the degree of each feeling for any two-color combinations. The proposed method can be expanded to three-color combinations. This proposal is expected to assist color designers, who can choose their usable color combinations from the candidates selected by the proposed method.

show abstract

New method for specifying color‐rendering properties of light sources based on feeling of contrast

Cited by 136 publications

References 15 publications

Selecting Conversion Phosphors for White Light-Emitting Diodes

Selecting Conversion Phosphors for White Light-Emitting Diodes

Color rendering: Beyond pride and prejudice

Proposal for selecting two‐color combinations with various affections. Part I: Introduction of the method

Contact Info

Product

Resources

About