INTRODUCTION Brief History of the Development of Artificial Light Sources Lighting Quality Aspects Aims, Functionality and Applications of Lighting and Light Sources Fluorescent Lamps and the Development of the Color Rendering Index Color Rendering Index: Current Definition Other Metrics of Color Quality: A Systematic View of Color Quality (Color Rendition) Metrics Aims and Structure of the Book COLOR APPEARANCE: PHENOMENA AND METRICS Human Eye Physiology, Color Perception and Cognitive Color Color Appearance Phenomena Distortion of Color Appearance Under Different Artificial Light Sources The System of Color Quality Metrics System of Subjective Attributes of Color Quality and Their Descriptors Summary: Lessons Learnt for Lighting Practice THE WAITE POINT OF THE LIGHT SOURCE Color Matching: the Metameric Effect Chromaticity of Unique White Preferred White Tones Summary: Lessons Learnt for Lighting Practice OBJECT COLORS: SPECTRAL REFLECTANCE, GROUPING OF COLORED OBJECTS AND COLOR GAMUT ASPECTS Sampling, Grouping and Weighting of Object Colors Based on Their Spectral Reflectance Properties Spectral Reflectance of Flowers Spectral Reflectance of Skin Tones Spectral Reflectance of Art Paintings The Leeds Database of Object Colors Summary: Lessons Learnt for Lighting Practice VISUAL COLOR QUALITY ASPECTS: REULTS AND CONSEQUENCES FROM VISUAL STUDIES Aims of Visual Color Quality Studies Methodology of Visual Color Quality Studies Visual Study on Color Fidelity (Color Realness) Based on Color Difference Adjustment Visual Study on the Semantic Interpretation of Color Differences and Color Rendering Indices Visual Color Quality Studies on Color Preference, Vividness and Naturalness Visual Color Quality Studies on Color Discrimination and Color Gamut Visual Experiments on Color Memory and on Cognitive Color Aspects Color Summary: Lessons Learnt for Lighting Practice VISUAL COLOR QUALITY EXPERIMENTS AT THE TECHNISCHE UNIVERSITÄT DARMSTADT Motivation and Aim of the Visual Color Quality Experiments Experiment on Chromatic Visual Clarity Brightness Matching of Strongly Metameric White Light Sources Correlated Color Temperature Preference for White Objects Color Temperature Preference of Illumination with Red, Blue and Colorful Object Combinations Visual Experiments on Color Quality in a Three-Chamber Viewing Booth Experiments on Color Preference, Naturalness and Vividness in a One-Chamber Viewing Booth Experiment on Long-Term Memory Colors Summary: Lessons Learnt for Lighting Practice CORRELATIONS OF COLOR QUALITY METRICS Sample Set of Test Light Sources Correlations Among Color Quality Metrics Using Their Own Test Color Samples Correlations Among Color Quality Metrics Using Different Sets of Test Color Samples Summary: Lessons Learnt for Lighting Practice OPTIMIZATION OF LED LIGHT ENGINES FOR HIGH COLOR QUALITY Optimization Concepts for Lighting Design State of the Art of LED Technology Comprehensive Spectral Modeling of LEDs (Colored Semiconductor LEDs and Phosphor- Converted White LEDs) Optimization Schemes for the Spectral Design of LED Light Engines Optimization for Color Fidelity (CIECRI 2012, CIE Ra, IES Rf 2015) Comprehensive Optimization for Different Color Quality Aspects Comprehensive Multi-Metric Color Quality Optimization by the Variation of LED Peak Wavelengths and LED Phosphor Systems Summary: Lessons Learnt for Lighting Practice HUMAN CENTRIC LIGHTING AND COLLOR QUALITY Principles of Human Centric Lighting and Color Quality The Circadian Stimulus in the Rea et al. Model Spectral Design for HCL Co-Optimizing Circadian Aspects and Color Quality Summary: Lessons Learnt for Lighting Practice CONCLUSIONS AND OUTLOOK