photometrically


pho·tom·e·try

P0265400 (fō-tŏm′ĭ-trē)n. Measurement of the properties of light, especially luminous intensity.
pho′to·met′ric (fō′tə-mĕt′rĭk), pho′to·met′ri·cal (-rĭ-kəl) adj.pho′to·met′ri·cal·ly adv.pho·tom′e·trist n.
Thesaurus
Adv.1.photometrically - by photometric means; "photometrically measured"