Historical Luminous Intensity

Chapter

Abstract

Efforts to quantify and standardize light intensity measurement have only really spanned the past couple hundred years, since the mid-19th century AD. This chapter sheds light on the many approaches that have been taken. The basis for the standard used to establish light intensity has moved from a candle to standard lamps to a carbon filament electric light to molten platinum at its freezing point to a theoretical Planckian blackbody emitter. This evolution will likely continue, but the standard SI unit for light intensity, the candela, still remains close to one old candle (within about 10%). Conversion factors between different light intensity measurement units are provided.

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Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Gig HarborUSA

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