5.1 The most direct and accessible methods for obtaining the color coordinates of object colors are by instrumental measurement using spectrophotometers or spectrocolorimeters with either hemispherical or bidirectional optical measuring systems. This test method provides procedures for such measurement by spectrophotometry using a bidirectional (0:45 or 45:0) optical measuring system. The method for color and color difference measurement using filter colorimeters is contained in Test Method E1347.

5.2 This test method is especially suitable for measurement of the following types of specimens for the indicated uses (see also Guide E179 and Practice E805):

5.2.1 Object-color specimens of any gloss level for color assessment.

5.2.2 Object-color specimens with physically flat, smooth surfaces from which to obtain data for use in computer colorant formulation.

5.2.3 Retroreflective specimens.

Note 1: To ensure inter-instrument agreement in the measurement of specimens with intermediate gloss, for formulation, or of retroreflective specimens, significantly tighter tolerances than those given in Practice E1164, Influx and Efflux Conditions, 45°:Normal (45:0) and Normal:45° (0:45) Reflectance Factor section, may be required for the instrument angles of illumination and viewing. Information on the required tolerances is being developed.

5.3 This test method is not recommended for measurement of specimens with bare metal surfaces for color assessment, for which the use of hemispherical measurement geometry, as with an integrating-sphere type instrument, is preferable (see Guide E179).

1.1 This test method covers the instrumental measurement of the reflection properties and color of object-color specimens by use of a spectrophotometer or spectrocolorimeter with a bidirectional optical measuring system, such as annular, circumferential, or uniplanar 45:0 or 0:45 geometry.

1.2 This test method is generally suitable for any non-fluorescent, flat object-color specimen. It is especially recommended for measuring retroreflective specimens and specimens of intermediate gloss.

1.3 Procedures required for the measurement of fluorescent object color are given in Practice E991 and Practice E2153.

1.4 Procedures required for the measurement of color using filter colorimeters are contained in Test Method E1347 and this standard does not address those instruments.

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

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.