ASTM E1164-09a

The most general and reliable methods for obtaining CIE tristimulus values or, through transformation of them, other coordinates for describing the colors of objects are by the use of spectrometric data. Colorimetric data are obtained by combining object spectral data with data representing a CIE standard observer and a CIE standard illuminant, as described in Practice E 308.

This practice provides procedures for selecting the operating parameters of spectrometers used for providing data of the desired precision. It also provides for instrument calibration by means of material standards, and for selection of suitable specimens for obtaining precision in the measurements.

1.1 This practice covers the instrumental measurement requirements, calibration procedures, and material standards needed to obtain precise spectral data for computing the colors of objects.

1.2 This practice lists the parameters that must be specified when spectrometric measurements are required in specific methods, practices, or specifications.

1.3 Most sections of this practice apply to both spectrometers, which can produce spectral data as output, and spectrocolorimeters, which are similar in principle but can produce only colorimetric data as output. Exceptions to this applicability are noted.

1.4 This practice is limited in scope to spectrometers and spectrometric colorimeters that employ only a single monochromator. This practice is general as to the materials to be characterized for color.

1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.6 This standard does not purport to address the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.