ASTM E1360-05(2019)

5.1 Notational systems that specify and identify colors have proved to be very useful. This practice describes how to assign an OSA-UCS notation to a color specimen. This notation gives its position within the color space determined by the Optical Society of America Committee on Uniform Color Scales to represent the closest possible approximation to a color space in which equal distances equate to equal visually perceived differences. The cuboctahedral sampling fills the color space with a more closely spaced set of samples than would a cubic lattice or samples placed on polar coordinates.

1.1 This practice provides a means for specifying the colors of objects in terms of the Optical Society of America Uniform Color Scales. Both computational and visual methods are included. The practice is limited to opaque objects, such as painted surfaces, viewed in daylight by an observer having normal color vision.

1.2 This practice does not cover the preparation of specimens. If the preparation of specimens is required in conjunction with this practice, a mutually agreed upon procedure shall be established.

1.3 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.