Colorimetry

Noboru Ohta earned his B.Sci., and Dr.Eng.from the University of Tokyo. In 1968, he joined Fuji Photo Film and From 1973, he spend three y ears under Gunter Wyszecki at the National Research Council of Canada. He has taught colorimetry and color reproduction at a variety of universities. he joined Rochester Institute of Technology in 1998, and is associated there with the Munsell Color Science Laboratory in the Center for Imaging Science. He has published more than 100 technical paper sin Japanese and English, and several books on colorimetry and color reproduction in Japanese, Chinese, and Korean. He has been active in a variety of academic societies, and also in standards organizations such as the Japanese Industrial Standards (JIS), the American National Standards Institute (ANSI), and the International Commission on Illumination (CIE). Alan Robertson earned his B.Sc and Ph.D. from the University of London, where he studied under David Wright. He then joined Gunter Wyszecki at the National Research Council of Canada and Spent 35 years there before retiring in 2000. He has published over 50 papers in journals and conference proceedings and has given more than 60 invited talks in 10 countries. He is former President of the international Color Association (AIC) and Vice President of the International Commission on Illumination (CIE). In 2005, he received the Godlove Award of the Inter-Society Color Council (ISCC) for long-term contributions in the field of color.

About the Authors ix

Series Preface xi

Preface xiii

Introduction xv

1 Light, Vision and Photometry 1

1.1 Light 1

1.2 Mechanism of the Human Eye 4

1.3 Adaptation and Responsivity of the Human Eye 7

1.4 Spectral Responsivity and the Standard Photometric Observer 9

1.5 Definition of Photometric Quantities 17

1.6 Photometric Units 21

1.7 Calculation and Measurement of Photometric Quantities 26

1.8 Relations Between Photometric Quantities 31

Note 1.1 Luminous Exitance, Illuminance, and Luminance of a Perfect Diffusing Plane Light Source 34

Note 1.2 Luminance and Brightness 36

2 Color Vision and Color Specification Systems 39

2.1 Mechanism of Color Vision 39

2.2 Chemistry of Color Vision 46

2.3 Color Specification and Terminology 48

2.4 Munsell Color System 52

2.5 Color System Using Additive Color Mixing 57

Note 2.1 Colorfulness, Chroma and Saturation 61

3 CIE Standard Colorimetric System 63

3.1 RGB Color Specification System 63

3.2 Conversion into XYZ Color Specification System 68

3.3 X10Y10Z10 Color Specification System 71

3.4 Tristimulus Values and Chromaticity Coordinates 74

3.5 Metamerism 76

3.6 Dominant Wavelength and Purity 78

3.7 Color Temperature and Correlated Color Temperature 82

3.8 Illuminants and Light Sources 85

3.9 Standard and Supplementary Illuminants 92

Note 3.1 Derivation of Color Matching Functions from Guild and Wright’s Results 96

Note 3.2 Conversion between Color Specification Systems 99

Note 3.3 Conversion into XYZ Color Specification System 101

Note 3.4 Imaginary Colors [X] and [Z] 105

Note 3.5 Photometric Quantities in the X 10 Y 10 Z 10 Color System 108

Note 3.6 Origin of the Term ‘Metamerism’ 109

Note 3.7 Simple Methods for Obtaining Correlated Color Temperature 110

Note 3.8 Color Temperature Conversion Filter 111

Note 3.9 Spectral Distribution of Black-body Radiation 113

4 Uniform Color Spaces 115

4.1 Uniform Chromaticity Diagrams 115

4.2 Uniform Lightness Scales (ULS) 122

4.3 CIE Uniform Color Spaces 127

4.4 Correlates of Perceived Attributes 132

4.5 Comparing CIELAB and CIELUV Color Spaces 134

4.6 Conversion of Color Difference 140

4.7 Color Difference Equations Based on CIELAB 143

Note 4.1 Calculation of Munsell Value V from Luminous Reflectance Y 144

Note 4.2 Modified CIELAB and CIELUV Equations for Dark Colors 146

Note 4.3 Other Color Difference Formulas 147

Note 4.4 Direct Calculation of Hue Difference ΔH* 150

5 Measurement and Calculation of Colorimetric Values 153

5.1 Direct Measurement of Tristimulus Values 153

5.2 Spectral Colorimetry 156

5.3 Geometrical Conditions for Measurement 158

5.4 Calculation of Colorimetric Values 161

5.5 Colorimetric Values in CIELAB and CIELUV Uniform Color Spaces 167

Note 5.1 Spectral Colorimetry of Fluorescent Materials 172

Note 5.2 Reference Standard for Reflection Measurements 173

6 Evolution of CIE Standard Colorimetric System 175

6.1 Additive Mixing 176

6.2 Subtractive Mixing 180

6.3 Maximum Value of Luminous Efficacy and Optimal Colors 184

6.4 Chromatic Adaptation Process 188

6.5 von Kries’ Predictive Equation for Chromatic Adaptation 191

6.6 CIE Predictive Equations for Chromatic Adaptation 194

6.7 Color Vision Models 197

6.8 Color Appearance Models 198

6.9 Analysis of Metamerism 204

Note 6.1 Color Mixing Rule 211

Note 6.2 Lambert–Beer Law 213

Note 6.3 Method for Calculating the Maximum Value of the Luminous Efficacy of Radiation 214

Note 6.4 Method for Calculating Optimal Colors 215

Note 6.5 Method for Obtaining Fundamental Spectral Responsivities 216

Note 6.6 Deducing von Kries’ Predictive Equation for Chromatic Adaptation 221

Note 6.7 Application of von Kries’ Equation for Chromatic Adaptation 223

Note 6.8 Application of CIE 1994 Chromatic Adaptation Transform 225

Note 6.9 Theoretical Limits for Deviation from Metamerism 226

7 Application of CIE Standard Colorimetric System 229

7.1 Evaluation of the Color Rendering Properties of Light Sources 229

7.2 Evaluation of the Spectral Distribution of Daylight Simulators 237

7.3 Evaluation of Whiteness 242

7.4 Evaluation of Degree of Metamerism for Change of Illuminant 244

7.5 Evaluation of Degree of Metamerism for Change of Observer 249

7.6 Designing Spectral Distributions of Illuminants 255

7.7 Computer Color Matching 261

Note 7.1 Computation Method for Prescribed Spectral Distributions 268

Appendix I Basic Units and Terms 271

AI.1 SI Units 271

AI.2 Prefixes for SI Units 272

AI.3 Fundamental Constants 272

AI.4 Greek Letters 272

Appendix II Matrix Algebra 275

AII.1 Addition and Subtraction of Matrices 276

AII.2 Multiplication of Matrices 277

AII.3 Inverse Matrix 277

AII.4 Transpose Matrix 278

Appendix III Partial Derivatives 281

Appendix IV Tables 285

References 321

Bibliography 327

Index 329