Colorimetry

Janos Schanda, PhD, is Professor Emeritus of the University of Pannonia in Hungary, where he taught colorimetry and visual ergonomics. He headed the Department of Image Processing and Neurocomputing between 1996 and 2000, and served as secretary of the CIE. He is a member of the advisory boards of Color Research and Application, Lighting Research and Technology, Light and Engineering, and Journal of Light and Visual Environment.

• Preface xviiContributors and Referees xxiPart I Historic retrospection1 Translation of CIE 1931 Resolutions on Colorimetry 1Translated by P. BodrogiDecision 1 1Decision 2 4Appendix to Decision 2 5Decision 3 5Decision 3a 8Decision 4 8Decision 5 82 Professor Wright’s Paper from the Golden Jubilee Book: The Historical and Experimental Background to the 1931 CIE System of Colorimetry 9W. D. WrightColor mixture and measurement in the Nineteenth Century 9American contributions to photometry and colorimetry, 1900–24 11The run-up to the 1931 observer: 1924–30 12The drama of 1931 17Postscript to 1931 21Note added in proof 22References 22Part II Colorimetric Fundamentals3 CIE Colorimetry 25János SchandaIntroduction 25CIE standard colorimetric observers 27The CIE 1931 standard colorimetric observer 29Determination of the r( λ), g(λ), b( λ) color-matching functions 29Derivation of the CIE XYZ trichromatic system from the CIE RGB trichromatic system 29Tristimulus values and chromaticity coordinates 31CIE 1964 standard colorimetric observer 35k10 in the tristimulus values of self-luminous objects for the 10 observer 36k10 in the tristimulus values of non-self-luminous objects for the 10 observer 36Chromaticity coordinates for the 10 observer 37Notes on the use of the CIE 1964 standard colorimetric observer 37CIE illuminants and sources 37CIE standard illuminant A and Planckian radiators 38Daylight illuminants 40CIE standard illuminant D 65 42CIE illuminants 43CIE sources and simulators for colorimetry 44Source A 44Sources B and c 45Source D 65 45Standards and recommendations for measuring reflecting/transmitting materials 47Terms used in conjunction with transmission and reflection measurement 47Phenomena 47Quantities to describe reflection and transmission 48Measuring geometries 49The sample plane and influx geometry 50Directional geometries 54Quantities using different measuring geometries 55Nonstandard geometries 55Recommended geometry for transmission measurements 55Standards of reflectance 57Uniform chromaticity diagram and uniform color spaces 58Uniform chromaticity diagram, CIE 1976 UCS diagram 59CIE 1976 uniform color spaces 60CIE 1976 (L*a* b*) color space, CIELAB color space 61Cie 1976 (L* u* v*) Color Space, Cieluv Color Space 64Descriptors of chromaticity 65Dominant/complementary wavelength and purity 65Correlated color temperature 67Whiteness 68Metamerism 70Special metamerism index: change in illuminant 71Special metamerism index: change in observer 72Summary 74Appendix A 74Appendix B 75References 764 CIE Color Difference Metrics 79Klaus WittIntroduction 79MacAdam’s experiments on variable stimuli 80Adams’ and Nickerson’s contribution to color difference evaluation 82Constant stimuli experiments 83CIE 1976 color difference formulas 84Testing and improving CIELAB 88Collection of new datasets 91Development of CIEDE 2000 91Further developments 97References 985 Spectral Color Measurement 101Yoshi OhnoIntroduction 101General practice in spectral color measurements 102Type of instruments 102Use of spectroradiometers for light source color measurement 103Irradiance mode 104Radiance mode 105Total flux mode 106Colorimetric calculation 107Use of spectrophotometers for object color measurements 107Geometries for reflectance color measurement 108Color calculation 109Critical parameters of spectrometers for color measurement 109Sampling interval and bandpass of instruments 109Sampling interval for object color measurement 110Effect of bandpass in object color measurement 112Effect of bandpass and scanning interval in measurement of light sources 112Wavelength scale error 116Uncertainties in measured spectral values 118Stray light in the monochromator 119Other sources of error 122Methods for corrections of error 123Correction of bandpass error 123ASTM E 308 123Stearns and Stearns’ method 124Extended method for bandpass correction 125Summary for bandwidth and scanning interval requirements 127Correction of stray light 128Uncertainty analysis 129Basic steps 130Numerical method for sensitivity coefficient 131Acknowledgment 132References 1326 Tristimulus Color Measurement of Self-Luminous Sources 135János Schanda, George Eppeldauer, and Georg SauterIntroduction 135Basic structure of a tristimulus colorimeter 136Input optics of a colorimeter for self-luminous objects 137Illuminance-meter-type input optics 137Luminance-meter-type input optics 138Image-taking colorimeters 139Spectral matching of the colorimeter 139Electronics 142Calibration 142Calibration with a standard source 142Calibration based on standard detectors 144Introduction 144The spectral responsivity based calibration method 144Calibration and measurement considerations 145Transfer of calibration 147Uncertainty estimation of a tristimulus colorimeter measurement 148Principle of the tristimulus calibration for a self-luminous object measuring tristimulus instrument 148Numerical example for a tristimulus calibration 151Calibration for selected spectral distributions 152Glossary 154Basic terms 154Specific terms 155References 1567 Color Management 159Ján Morovič and Johan LammensIntroduction 159Color reproduction objectives 160Viewing a pair of colors 161Conceptual stages of color reproduction 163Device color spaces 164Device characterization and calibration 165Color appearance model 166Color and image enhancement 166Color gamut mapping 167Completing the process 168The ICC color management framework 168sRGB color management 170Challenges of color management 171Does color need to be managed? 172Analog color management 174Watercolor reproduction scenario 176Original to scan 177Challenges of scanner characterization 178Scanner characterization models 180Scanner ICC profiles 181Scanned watercolor 182Scan to display 182Challenges of display characterization 183Display characterization models and their implementation in profiles 183Transforming scanned data to data for display 184Editing and page layout 185Proofing 188Proof printer calibration 189Proof printer characterization 190Rendering intents for proofing 191Evaluation of proof prints 192Challenges and opportunities 193Poster and leaflet production 194Future opportunities 195Self-calibrating and self-profiling devices 195Workflow automation 196Automatic adaptation to viewing environment 198Spatial processing 200Smart CMMs 200Multispectral imaging (CIE TC8-07) 202Conclusion 202Acknowledgments 202References 2038 Color Rendering of Light Sources 207János SchandaIntroduction 207The official CIE test sample method of color rendering evaluation 208Recent investigations to update the color-rendering index calculation 211Supplementary methods to describe color quality of light sources 213Summary 214References 215Part III Advances in colorimetry9 Color-Matching Functions: Physiological Basis 219Françoise Viénot and Pieter WalravenThe link between colorimetry and physiology 219The definition of cone fundamentals 220Historical background 220Decision by CIE 220Available experimental data 220State of the art in physiology 220In vitro measurements 220The principle of univariance 221Dartnall nomogram: dilute pigment: effective transmission optical density 221Available psychophysical measurements 222Spectral sensitivity functions of dichromats and the König hypothesis 222Spectral sensitivity functions of isolated cone mechanisms 222Short description of colorimetric databases 223Extending colorimetric data from 10 field to any field size from 10 to 1 226The cone fundamentals 226Linear transformation that yields the 10 cone fundamentals 227Validation of cone fundamentals 228Calculation scheme from dilute photopigment spectral absorbance to color-matching functions, and reverse 228Lens and other preretinal media 228Macular pigment 229Calculation scheme from dilute photopigment spectral absorbance to cone spectral absorbance, and reverse 229S-cone fundamental from 510 to 615 nm (2 field and 10 field) 231Extension to any field size 231The aging observer 232The calculation of tristimulus values 233CIE recommendations from CIE and final tables 234Discussion and perspectives 235An isoluminant fundamental chromaticity diagram 235Units and luminous efficiency function 235The l, s chromaticity diagram 236A CIE-like chromaticity diagram 237Individual variations 238At the receptoral level 238Postreceptoral processing: weighting L-signals and M-signals for luminance 238Examples of applications: The future 238Color vision deficiencies 238Observer metamerism 239Color differences 239Color appearance models 239Conclusion 240Acknowledgments 240References 24010 Open Problems on the Validity of Grassmann’s Laws 245Michael H. Brill and Alan R. RobertsonDefinition of the problem 245Historical review 246Theoretical approaches 248Generalizations of grassmann additivity 248Theory of transformation of primaries 250Numerical experiment 251Summary of the method 251Results and discussion 252Conclusion 254Activities of CIE TC 1–56 254The future 257References 25811 CIE Color Appearance Models and Associated Color Spaces 261M. Ronnier Luo and Changjun liIntroduction 261Viewing conditions 262Stimulus 262Proximal field 263Background 263Surround 263Adapting field 263Color appearance datasets 263Chromatic adaptation transforms 264Light and chromatic adaptation 264Physiological mechanisms 264Chromatic adaptation 264Development of the CAT02 used in CIECAM 02 266CIE Color appearance models 268CIECAM97s 269Ciecam 02 270Color appearance phenomena 271Chromatic adaptation 271Hunt effect 273Stevens effect 274Surround effect 275Lightness contrast effect 276Helmholtz–Kohlrausch effect 276Helson–Judd effect 277Uniform Color Spaces based on CIECAM 02 277CIECAM02-based color spaces 277Comparing the performance of the new UCSs with some selected color models 278Conclusions 280References 281Appendix A: chromatic adaptation transform: CAT 02 284Part 1: Forward Mode 284Part 2: Reverse Mode 285Appendix B: CIE color appearance model: CIECAM 02 286Part 1: The Forward Mode 286Part 2: The Reverse Mode 29112 Image Appearance Modeling 295Garrett M. Johnson and Mark D. FairchildIntroduction 295From simple to complex color appearance 296Image appearance modeling 300The general iCAM framework for image appearance 301Specific implementations of image appearance models: high-dynamic range tone-mapping 308Testing high-dynamic range rendering algorithms 312An implementation of image appearance for calculating image differences 314Spatial frequency adaptation 318Calculating image differences 319Conclusions and future considerations 320References 32113 Spatial and Temporal Problems of Colorimetry 325Eugenio Martinez–UriegasIntroduction 325Radiometry, photometry, colorimetry, and human vision 325Standards of color: the role of biology and psychophysics 326Spatial and temporal constraints of colorimetry: a selective overview 329Spectral, spatial, and temporal dimensions of visible light 329Classical separation of spatial, temporal, and color vision 330Two examples of spatial limitations of colorimetry 331Representation of spatial and temporal properties of visible light 335Spatial and temporal distributions of visible light 335Detection and discrimination thresholds 338Visual multiplexing of spatiotemporal chromatic and achromatic information 340Developing CSF standards 342General approach: data-based or theory-based standard 342Initial results 343Multiscale colorimetry: a spatiotemporal path forward 345Example of multiscale image decomposition 345Scale-shifting conjecture 348Multiscale colorimetry: a spatiotemporal path forward 348Summary thoughts 352References 35214 The Future of Colorimetry in the CIE 355Robert W.G. HuntIntroduction 355Color matching 355Color difference 357Color appearance 359Sources of funds 362References 362Appendix 1 Measurement Uncertainty 365Georg SauterIntroduction 365Definitions and types for the evaluation of uncertainty 366Definitions of terms 366Types for the evaluation of uncertainty 367Model of evaluation of uncertainty 368Monte Carlo method 369Model with two or more output quantities 371Expanded uncertainty 373Steps for evaluating uncertainty 373Practical examples 374Determination of the spectral irradiance of a source 375Principle of a spectral irradiance measurement 375Operation of a spectral irradiance standard 376Mechanical alignments 378Uncertainty Budget 379Determination of f1 0 values 383Uncertainty of f1 0 values with Monte Carlo method 386References 387Appendix 2 Uncertainties in Spectral Color Measurement 389James L. GardnerIntroduction 389Tristimulus values 390Uncertainty propagation 392Tristimulus uncertainties by component 393Random component effects 394Systematic component effects 394Propagation from tristimulus uncertainties to colour-value uncertainties 396Methods of calculation for color triplets 397(x,y,Y) color coordinates 397(u,v,Y) color coordinates 398(u’, y’, Y) color coordinates 398(L *, a*, b*) color coordinates 399(L*, C*, h) color coordinates (based on a*, b*) 399(L*, u*, v) Color Coordinates 400(L*, C*, h) Color Coordinates (based on U*, V*) 401(L*, s*, h) Color Coordinates (based on U*, V*) 401Spectral measurement as a transfer 401Uncertainty of the reference values 402Relative scaling of the measured spectral values 403Random scaling components 403Systematic scaling components 403Offsets in the spectral values 403Random offset components 404Systematic offset components 404Wavelength errors 404Random wavelength offsets 405Systematic wavelength offsets 405Determining measurement components 405Background offsets 406Noise versus drift 406Source noise 407Band-limited spectra 407Wavelength uncertainties 407Nonlinearity 408Corrections 408Conclusion 409References 409Appendix 3 Use of CIE Colorimetry in the Pulp, Paper, and Textile Industries 411Robert Hirschler and Joanne ZwinkelsIntroduction 411Pulp and paper applications 411Introduction 411Beneficiaries of CIE colorimetry 413CIE illuminant C and CIE standard geometry d/ 0 413Other CIE standard illuminants and standardized light sources 415CIE color spaces 416CIE reference standards 416CIE whiteness and tint equations 418Harmonized Terminology 419Driving force in the development of CIE colorimetry 419Establishment of new CIE technical committees 419Practical simulator of illuminant D 65 420Future needs 422Conclusion 422Textile applications 423Introduction 423CIELAB color space and its derivations 423Characterization of the buildup of colorants and of colorant combinations 423Standard Depth (SD) 424Color difference evaluation 425Shade sorting, tapering 425Fastness evaluation 427Determination of whiteness 427Recipe formulation 429Future needs 429Conclusion 430References 430Appendix 4 List of CIE Publications 435Recommendations 435Standards 435Technical committee reports 436Proceedings of the sessions 441Discs and other publications 442Special publications 442CIE publications on CD-ROM 443Glossary 445Index 453

"This is a definitive reference book for the CIE system." (CHOICE, February 2008)