Terms Used in Lighting

This chapter serves as the foundation for understanding the language and concepts of the lighting industry. Lighting design and technology are rich fields with a diverse vocabulary. In this chapter, readers will become acquainted with key terms that underpin the study of lighting, including the following. Section 1.1 defines illuminance as the measure of the amount of light that falls on a surface, crucial in lighting design and application. Section 1.2 introduces luminance, which describes the amount of light reflected or emitted from a surface as perceived by an observer. Section 1.3 explores color temperature, a fundamental concept in lighting that characterizes the warmth or coolness of light. Section 1.4 explains color rendering index, a metric that quantifies how accurately a light source renders colors, essential in applications such as retail and art lighting. Section 1.5 details spectral power distribution, which describes the distribution of radiant power emitted by a light source at each wavelength, influencing the perceived color and quality of light. Section 1.6 discusses flicker, the rapid and repetitive changes in light intensity, with an emphasis on its impact on visual comfort and health. Section 1.7 defines glare as excessive and uncontrolled brightness, often causing discomfort and reduced visibility. This chapter introduces these terms and concepts with clarity, preparing readers for an in-depth exploration of architectural interior lighting. It provides a solid foundation for understanding the principles and technologies discussed in subsequent chapters.