ASTM E1164-23 Standard Practice for Obtaining Spectrometric Data for Object-Color Evaluation

The standard “ASTM E1164-23 Standard Practice for Obtaining Spectrometric Data for Object-Color Evaluation” published by the American Society for Testing and Materials (ASTM) describes the instrumental measurement requirements, calibration procedures, and material standards needed to obtain precise spectral data for calculating the colors of objects.

This application contains parameters that must be specified when spectrophotometric measurements are required for certain methods, applications or specifications. Most parts of this application apply to spectrophotometers that can produce spectral data as output and to spectrocolorimeters, which are similar in principle but can only produce colorimetric data as output. Exceptions to this applicability are noted. This application is general in scope rather than specific to instruments or materials.

For the purposes of this standard, in addition to the terms and definitions given in the "ASTM E284-22 Standard Terminology of Appearance" standard, the following definitions apply:

• Annular is the descriptor for geometry with directional illumination (in imaging) where the illuminator provides radiation that is continuously and uniformly distributed across 360 degrees of the azimuth of the measurement or to which the receiver has sensitivity.
• Environmental refers to the descriptor for directional illuminated (or imaging) geometry in which the illuminator provides radiation in many rays (or directions) distributed normally at uniform intervals throughout the 360 ​​degrees of the azimuth of the measurement, or for which the receiver has sensitivity. The number and angular distribution of rays (or directions) shall be specified.
• Rotation angle refers to the angle that specifies the orientation of the sample when rotated about a selected axis fixed in it (for plane samples, usually the normal to the sample), and in retroreflection, the angle that specifies the orientation after rotation about the retroreflector axis.
• A spectrocolorimeter is a dispersive element (such as a prism, grating, or interference filter or wedge) that can normally only produce colorimetric data (such as tristimulus values ​​and derived color coordinates) as output, but not the underlying spectral data from which the colorimetric data are derived.
• Single plane is a descriptor for illumination and imaging geometry in which the illuminator and receiver axes and the perpendicular to the sample surface are in the same plane. Thus, directional illumination or imaging is provided by a single beam or by two beams 180 degrees apart in azimuth. The number of beams and their angular distribution must be specified.

This standard provides procedures for selecting the types and operating parameters of spectrophotometers used to provide data for calculating the International Commission on Illumination (CIE) color system values ​​and other color coordinates for documenting the colors of objects. The important steps in the calibration of such instruments and the material standards required for these steps are described. Guidelines for selecting samples to obtain the highest measurement accuracy are given. The parameters that must be specified when spectrophotometric measurements are required in specific test methods or other documents are defined.

The most direct and accessible methods of obtaining CIE values ​​or other coordinates that describe the colors of objects through their transformation are the use of spectrophotometric 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 the standard “ASTM E308-22 Standard Practice for Calculating Colors of Objects Using the CIE System”.

This application provides a procedure for selecting the operating parameters of the spectrophotometers used to provide data with the desired sensitivity. It also allows the selection of appropriate samples to achieve instrument calibration and precision in measurements through material standards.

Among the numerous testing, measurement, analysis and evaluation studies that our organization has provided for businesses in various sectors, it also provides testing services defined in the "ASTM E1164-23 Standard application for obtaining spectrometric data for object-color evaluation" standard with its trained and expert staff and advanced technological equipment.