Division 844 > Division 844 Facilities > Spectrophotometry Spectrophotometry Overview Spectrophotometry is the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. While relatively simple in concept, determining the reflectance or transmittance involves careful consideration of the geometrical and spectral conditions of the measurement. We maintain the national scales for reflectance and transmittance in the ultraviolet, visible, and near-infrared spectral regions (250 nm to 2500 nm). Contents Facilities Reference Instruments Reflectance Transmittance Commercial Instrument Services References For technical information or questions, contact: David Allen Phone: (301) 975-3680 FAX: (301) 840-5700 Email: david.allen@nist.gov For recalibration of SRMs 930, 1930, 2030, and 2031, please contact: Melody Smith Phone: 301-975-4115 FAX: 301-977-0587 Email: melody.smith@nist.gov OTD Home Page   |   Site Comments Online: September 1997   -   Last updated: February 2008