Optical Radiation Measurements

Optical Properties of Materials Measurements

Technical Contacts:
David W. Allen
Tel: 301/975–3680
E–mail: david.allen@nist.gov

Maria E. Nadal
Tel: 301/975–4632
E–mail: maria.nadal@nist.gov

Do not ship instruments or standards to the mailing address listed below. Contact the technical staff for the shipping address.

Mailing Address:
National Institute of Standards and Technology
100 Bureau Drive, Stop 8442
Gaithersburg, MD 20899-8442
Fax: 301/840-8551

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This laboratory's quality system is based on the ANSI/NCSL Z540–1–1994 standard and the ISO/IEC Guide 25.

Spectral Transmittance Filters (38010C–38040C)

NIST supplies to the customer standards of spectral transmittance for checking the photometric scale of spectrophotometers. These are either 30 mm polished glass disks or 51 mm polished glass squares, 2 mm to 3 mm thick, designated as cobalt blue, copper green, carbon yellow, and selenium orange. The relative expanded uncertainty ranges from approximately 0.2 % to 0.3 % of the value. Information provided to the user includes values of transmittance at 25 ° at 10 nm intervals from 380 nm to 770 nm, the estimated uncertainty of each value, and data as to the effect of temperature change on transmittance at each wavelength.

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Wavelength Standards (38050C)

NIST supplies to the customer holmium oxide glass standards for checking the ultraviolet and visible wavelength calibrations of recording spectrophotometers having a bandpass less than 2 nm. These are made of polished Corning 3130 glass, 51 mm x 51 mm, approximately 2.5 mm thick. A table of wavelengths of minimum transmittance is provided in the report to the user. The expanded uncertainty is 0.2 nm.

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Wavelength Standards (38051C)

NIST supplies to the customer holmium oxide glass standards for checking the ultraviolet and visible wavelength calibrations of recording spectrophotometers having a bandpass less than 2 nm. These are made of polished Corning 3130 glass cuvette size [ 11 mm x 15 mm ]. A table of wavelengths of minimum transmittance is provided in the report to the user. The expanded uncertainty is 0.2 nm.

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Special Tests of Spectral Reflectance (38060S)

Measurements of spectral reflectance can be made for the wavelength region 250 nm to 2500 nm for neutral, non–fluorescent submitted test items. In general, measurements are performed at room temperature on test items with dimensions from 2 cm to 30 cm perpendicular to the incident beam. Two different measurements are performed of both specular and diffuse reflectance at angles, wavelengths, and polarizations specified by the customer. For the directional–hemispherical geometry incident angles of 0° and 6° are possible, and the later can be measured with the specular component either included or excluded. Uncertainty estimates will be given and will depend on the optical characteristics of the submitted test item and the instrument used to perform the measurement. Arrangements for these measurements on submitted test items must be made before shipment. The decision to perform the measurements and selection of the instruments to be used will rest with NIST. Test items not accepted for measurement will be returned.

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Special Tests of Spectral Transmittance (38061S)

Measurements of spectral transmittance can be made at wavelengths from 250 nm to 2500 nm for non–fluorescent submitted test items. In general, measurements are performed at room temperature with the incident beam normal to the front surface of the test item. Items with dimensions from 1 cm to 5.1 cm perpendicular to the incident beam are routinely accommodated. Other sizes and measurement conditions are possible in consultation with NIST staff. Uncertainty estimates will be given and will depend on the optical characteristics of the submitted test item and the instrument used to perform the measurement. Arrangements for these measurements on submitted test items must be made before shipment. The decision to perform the measurements and selection of the instruments to be used will rest with NIST. Test items not accepted for measurement will be returned.

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Specular Gloss (38090S)

Measurements of specular gloss of customer–supplied test items can be performed for 20, 60, and 85 degree geometries according to the specifications given in ASTM D523 and ISO 2813. Arrangements for these measurements on submitted test items must be made before shipment. The decision to perform the measurements will rest with NIST, and test items not accepted for measurement will be returned.

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Special Test of 0°/45° Surface Color (38091S)

Measurements of 0°/45° surface color can be made at wavelengths from 360 nm to 800 nm at 5 nm increments for non–fluorescent submitted test items. Measurements of spectral reflectance factor are performed at room temperature with the incident beam normal to the front surface of the test item and the receiver at a viewing angle of 45°. Items with dimensions from 5.08 cm to 10.2 cm perpendicular to the incident beam are routinely accommodated. Other sizes and measurement conditions are possible in consultation with NIST staff. The customer specifies the illuminant(s), observer(s), and color space(s) for calculations of the surface color. Uncertainty estimates will be given and will depend on the optical characteristics of the submitted test item. Arrangements for these measurements on submitted test items must be made before shipment. The decision to perform the measurements will rest with NIST. Test items not accepted for measurement will be returned.

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New Services Coming Soon

X–Ray Film Step Tablet Transmission Density Standard (38100C)

Recalibration of an X–Ray Film Step Tablet Transmission Density Standard (38110C)

Photographic Film Step Tablet Transmission Density Standard (38120C)

Recalibration of a Photographic Film Step Tablet Transmission Density Standard (38130C)

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References—Spectrophotometric Measurements

NIST Measurement Services: Spectral Reflectance, P. Y. Barnes, E. A. Early, and A. C. Parr, Natl. Inst. Stand. Technol. Spec. Publ. 250–8 (revised 1997).

NIST High Accuracy Reference Reflectometer–Spectrophotometer, J. Res. Natl. Inst. Stand. Technol. 101(5) 619 (1996).

45 Degrees/0 Degrees Reflectance Factors of Pressed Polytetrafluoroethylene (PTFE) Powder, Natl. Inst. Technol. Stand. Tech. Note 1413 (1995).

Compliance in spectrometry:–quality assurance of spectrophotometric measurements at NIST, J. J. Hsia, T. C. Larason, P. Y. Barnes, Spectrophotometry, Luminescence and Coulour; Science & Compl. (1995).

Comparison of Regular Transmittance Scales of Four National Standardizing Laboratories, K. L. Eckerle, J. Bastie, J. Zwinkels, V. Saprintsky, and A. Ulyanov, Color Res. Appl. 18 (1), 35–40 (Feb. 1993).

International Intercomparison of Regular Transmittance Scales, K. L. Eckerle, E. Sutter, G. H. C. Freeman, G. Andor, and L. Fillinger, Metrologia 27, 33–38 (1990).

NBS Measurement Services: Regular Spectral Transmittance, K. L. Eckerle, J. J. Hsia, K. D. Mielenz, and V. R. Weidner, Natl. Bur. Stand. (U.S.), Spec. Publ. 250–6 (July 1987).

Establishing a Scale of Directional–Hemispherical Reflectance Factor 1: The Van den Akker Method, W. H. Venable, Jr., J. J. Hsia, and V. R. Weidner, J. Res. Natl. Bur. Stand. (U.S.), 82 (1), 29 (July–Aug. 1977).

Permanence of Glass Standards of Spectral Transmittance, K. S. Gibson and M. A. Belknap, J. Res. Natl. Bur. Stand. (U.S.), 44, 463 (May 1950).

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Date created: 06/30/1999
Last updated: 10/06/2006