The options available in methods for the measurement of color or color-difference are many. These involve choices in: (1) specimens, (2) geometric and spectral properties of instruments, (3) calibration bases for standards used, (4) procedure for sample handling including conditioning, (5) procedure for taking data, and (6) equations for converting instrumental data to final results. Once the measurements have been made, it is essential to document what has been done for the purpose of interlaboratory comparisons, or for future use. A sample form is provided in Fig. 1 to record identifying information applicable to any instrumental method of color or color-difference measurement.

Refer to Guide E179, Practices E991, E1164, E1345, E1708, E1767, E2152, and E2194 and Test Methods D5386, D6166, E1247, E1331, E1347, E1348, and E1349, for specific details of measurements.

1.1 This practice covers the documentation of instrumental measurement of color or color difference for current communication or for future reference. The practice is applicable to instrumental measurements of materials where color is seen by reflected, transmitted or emitted light and any combinations of one or more of these processes. The practice is recommended for documentation of methodology in interlaboratory color-measurement programs.

1.2 Providing an adequate identification of an instrumental measure of color or color-difference involves documenting the metadata necessary for archiving and future use of the measurement data collected. The metadata can be divided in five parts:

1.2.1 Nature and source of available samples and the form of specimens actually measured,

1.2.2 Instrumental conditions of measurement, including instrument geometrical and spectral conditions of measurement,

1.2.3 Standards used,

1.2.4 Data acquisition procedure, and

1.2.5 Color scales employed.

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