Table of Contents  » Facilities  » Services  » References   Color and Appearance - Facilities We maintain the national reference instruments for measurements of 0°/45° surface color and specular gloss at the three standard geometries of 20°, 60°, and 85°. Reference Instruments Colorimeter Glossmeter Reference Instruments The conditions of measurement and measured quantities for the two reference instruments are given in Table 1. Additional details for each instrument are given below. Colorimeter The Reference Colorimeter is the national reference instrument for spectral reflectance factors of colored, non-fluorescent samples at room temperature. The colorimeter performs measurements of the 0°/45° spectral reflectance factors on samples with widths from 5 cm to 10.2 cm, at wavelengths from 360 nm to 800 nm at 5 nm increments. The sample is illuminated over a 12 mm square at normal incidence using a beam with a 5 nm bandwidth and linear polarization. The illumination is provided by an incandescent or Xe-arc lamp, a ½m double-grating monochromator, an aperture and reflective optics in a telecentric arrangement, and a polarizer. Light reflected from the sample is collected at an angle of 45 degrees from the normal and focused by a telecentric lens system onto a silicon photodiode. Color values are calculated from the measured reflectance factor and specified illuminant, observer, and color space. Photo of Reference Colorimeter Glossmeter The Reference Goniophotometer is the national reference instrument for specular gloss at the three standard specular geometries of 20°, 60°, and 85. The basis of the gloss measurements is a collimated white light beam (CIE Illuminant C or A) incident on the sample with a photopically corrected detector measuring the reflected specular beam in a defined geometry. This instrument complies with the geometrical and spectral conditions specified by the American Society for Testing Materials (ASTM) D523 and the International Organization for Standardization (ISO) 2813 documentary standards for the measurement of specular gloss of non-metallic surfaces at fixed specular geometries. Photo of Reference Goniophotometer Table 1. Measurement conditions for color and appearance reference instruments.   Colorimeter Glossmeter Condition     Geometrical     Illumination Angle 0° 20°, 60°, and 85° Viewing Angle 45° 20°, 60°, and 85° Sampling Aperture 12 mm 30 mm Spectral     Wavelength 360 nm to 800 nm Photopic Bandwidth 5 nm   Polarization 0° to 90° None Sample Size 50 mm to 100 mm 50 mm to 100 mm Measurand     Quantity Spectral Reflectance Factor, R Specular Gloss Technique Relative to Spectralon Relative to primary gloss standard Range 0.001 to 1 0 to 110 Uncertainty (k=2) 0.1 % to 0.6 % 0.3 % < Contents Top Services > For technical information or questions, contact: Maria E. Nadal Phone: (301) 975-4632 FAX: (301) 869-5700 Email: maria.nadal@nist.gov Ted Early Phone: (301) 975-2343 FAX: (301) 869-5700 Email: edward.early@nist.gov OTD Home Page   |   Site Comments Online: October 2003