ABSTRACT
Late Victorian photometry was shaped by new players wielding new devices and seeking new goals: gas inspectors and astronomers with practiced eyes or sensitive emulsions. With observers closeted in darkened rooms, the measurement of light remained an intensely individualistic affair, based on a personal judgement of a light source by a single pair of eyes. But a variety of processes-social, technological and scientific-transformed the brightness of light in the late 19th century from the passing concern of a few disparate individuals to a subject employed and studied by groups.
