ABSTRACT
The early 20th century shifted the domain of light measurement. Self-described illuminating engineers were calling for standards and scientific methods of measurement. The emphasis of photometry shifted from routine gas testing to the measurement of electric-lamp intensities and illumination. Visual methods became highly refined, and were joined increasingly by photographic and photoelectric photometry. Light measurement during this period was part of a broader trend towards quantitative methods, standardization and the growth of science-based industry1.
