Principles of
Color Technology
SECOND
EDITION
Fred W. Billmeyer, Jr.
Professor of Analytical Chemistry
Department of Chemistry
Rensselaer Polytechnic Institute
Troy, New York
Max Saltzman
Adjunct Professor of Chemistry
Rensselaer Polytechnic Institute
and Research Specialist
Institute of Geophysics and Planetary Physics
University of California, Los Angeles
A Wiley-Interscience Publication
J O H N WILEY & S O N S
New York • Chichester • Brisbane • Toronto • Singapore
Contents
Chapter 1 What is Color? 1
A.
B.
C.
D.
E.
What This Book Is About 1
The Physical Stimulus 2
Sources of Light 3
How Materials Modify Light 8
Transmission 8
Absorption 10
Scattering 11
Other Aspects of Appearance 13
Spectral Characteristics of Materials 13
Detecting Light and Color 15
Summary 17
The Description of Color 17
The "Desert Island" Experiment 18
Color Coordinates 19
The Appearance of Color 20
Light Sources, Color Rendition, and Chromatic Adaptation
Metamerism 21
Summary 23
Chapter 2
A.
Describing Color
20
25
Systems Based on Physical Samples 25
Random Arrangements 25
Arrangements Based on Colorant Behavior 26
Arrangements Based on Color-Mixing Laws 26
The Ostwald System 26
Arrangements Based on Steps of Equal Visual Perception
The Munsell System 28
The OSA Uniform Color Scales System 30
28
xi
B.
C.
D.
The Natural Color System 30
Chroma Cosmos 5000 30
The Universal Color Language 31
The CIE System 34
CIE Standard Sources and Illuminants 34
CIE Standard Observers 37
The 1931 CIE Standard Observer 37
The 1964 CIE Supplementary Standard Observer 40
Calculating the CIE Tristimulus Values 44
Chromaticity Coordinates and the Chromaticity Diagram
Metamerism 52
More Nearly Uniformly Spaced Systems 56
Linear Transformations of the CIE System 57
Opponent-Type Systems 59
Nonlinear Transformations of the CIE System 60
Lightness Scales 60
Uniform Color Spaces 62
One-Dimensional Color Scales 64
Yellowness Scales 65
Other One-Dimensional Color Scales 66
Limitations of One-Dimensional Color Scales 66
Whiteness 66
Summary 66
Chapter 3
A.
B.
C.
D.
Color and Color-Difference Measurement
Basic Principles of Measuring Color 67
Examination 67
Assessment 68
THINK and LOOK 69
The Sample 69
Samples for Analysis 69
Form Suitable for Inspection 70
Again, LOOK 71
Visual Color Measurement 71
Sample and Single Standard 72
Sample and Multiple Standards 73
Instruments Using the Eye as Detector 75
Disk Colorimetry 75
Color Comparators for Liquids 76
More Refined Instruments 76
Instrumental Color Measurement 77
Classification of Methods 77
Unaltered Light 77
Three Colored Lights 77
Monochromatic Light 78
Spectrophotometry 78
Source, Monochromator, and Detector 78
Abridged Spectrophotometry 79
67
47
F.
G.
Sample Illumination and Viewing 79
Calculation of CIE Coordinates 81
Standardization and Accuracy 82
Colorimetry 85
Source-Detector Response 85
Coordinate Scales 86
Instrument Metamerism 87
Standardization and Differential Use 87
Selecting a Color-Measuring Instrument 89
Features of Current Instruments 90
Speed 90
Reproducibility 90
Computing Power 90
Peripherals 90
Spectrophotometers 90
Diano Hardy II 90
Diano Match-Scan 91
Hunter D54 Series 92
ACS Spectro-Sensor 92
IBM 7409 Series 92
Abridged Spectrophotometers 93
Macbeth 2000 Series 93
Colorimeters 95
Hunter D25 and Gardner XL Series 95
Macbeth 1500 Series 96
Color-Difference Assessment 96
Assessment by Visual Methods 97
Assessment by Instrumental Methods 97
Equations Based on Munsell Data 98
Equations Based on Just-Perceptible-Difference Data 99
Equations Based on the Standard Deviation of Color
Matching 100
The Current CIE Recommendations 101
Perceptibility Versus Acceptability 105
Appropriate Use of Color-Difference Calculations 105
Color Specification and Tolerances 106
Summary 109
Chapter 4
A.
B.
C.
Colorants 111
Some Matters of Terminology 111
Dyes Versus Pigments 112
Solubility 113
Chemical Nature 114
Transparency 114
Presence of a Binder 115
Summary 115
Classification of Colorants 115
D.
E.
F.
G.
The Colour Index 115
Special Colorants—Fluorescents and Flakes 118
Selecting the Colorants to Use 119
Sources of Information 120
Experienced Personnel 120
Suppliers of Colorants 120
Books and Periodicals 120
The User's Experience 121
General Principles in Choosing Colorants 121
Color as an Engineering Material 122
The Various Meanings of Color 122
Engineering Properties of Colorants 124
Color Gamuts 125
The Selection of Colorants 130
A Look Ahead 131
Summary 132
Chapter 5 The Coloring of Materials in Industry
A.
B.
C.
Color-Mixing Laws 134
Additive Mixing 134
Simple-Subtractive Mixing 137
Complex-Subtractive Mixing 139
Color Matching 141
Types of Matches 141
Invariant Matches 142
Conditional Matches 144
Selection of Colorants 145
Objectives of Color Matching 146
Original Formulations 146
Matching Identical Materials 147
Matching Different Materials 147
Colorant Identification 147
Coordinated Colors 148
Colorant Replacement 149
Strength of Colorants 149
Visual Methods 150
Instrumental Methods—Dyes 150
Instrumental Methods—Pigments 151
Depth of Shade 152
The Initial Match 152
Visual Matching 152
Instrumental Aids 153
Computer-Assisted Formulation 163
Adjusting the Match 167
Color Control in Production 168
Monitoring 169
The Value of Instruments 169
The Effect of Process Variables 169
More Than Measurement Alone 169
133
D.
Adjusting 169
Controlling 171
Those Other Aspects of Appearance
Chapter 6
A.
B.
C.
D.
Problems and Future Directions in Color Technology
173
Unsolved Problems 173
Problems Related to Colorimetry 173
Standard Sources 173
Observer Variability 174
Indices of Metamerism 176
Color-Rendering Indices 177
The Color-Difference Problem 178
Problems Related to Measurements 180
Instrument Agreement 180
Problems of Geometry 182
Special Samples 182
Problems Related to Computer Color Matching 183
Problems with Conventional Samples and Theory 183
Special Samples 185
Future Directions 186
The Specification of Color Appearance 186
Subjective (Perceptual) Color Terms 186
Objective Color Terms 187
Chromatic Adaptation 188
Advanced Turbid-Medium Theory 189
Educational Opportunities 191
Continuing-Education Courses 192
University Courses 192
Technical Society Courses 192
Manufacturers' Courses 192
Professional Societies 193
The Color Literature 194
Back to Principles 194
Chapter 7
A.
B.
C.
D.
E.
F.
G.
H.
172
Annotated Bibliography
197
Books 197
Journals and Collected Works 200
Color Perception, Description, and Appearance
Color-Order Systems 203
Color Measurement 204
Color-Difference Measurement 206
Colorants 208
Color Matching 209
202
Bibliography 213
Author Index 231
Subject Index 234
XV