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. Designation: E284-25 INTERNATIONAL Standard Terminology of Appearance1 This standard is issued under the fixed designation E284; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. INTRODUCTION Appearance, including the appearance of objects, materials, and light sources, is of importance in many arts, industries, and scientific disciplines. Appearance terms are used in a wide range of ASTM standards as wellas other documents of concern in standardization,testing,and specification.The purpose of this terminology standard is to define terms relating to the description of appearance Definitions are of two distinctly different kinds. A descriptive definition reports existing usage, whereas a prescriptive definition is an invitation to use a term in a specific way. By agreement of ASTMCommitteeE12on ColorandAppearance,the definitions in this terminology standard are taken to be prescriptive in nature. Committee E12 thereby assumes a position of leadership in usage. Terms and definitions in several terminology standards and vocabularies other than ASTM (see References), as well as other ASTM terminology standards, have been considered for inclusion in this terminology standard. An effort has been made to achieve greater accuracy, brevity, clarity, precision, and internal consistency, and to draw distinctions that are useful in the practical measurement and specification of appearance. Suggestions for additions or revisions to this terminology standard are welcome. 1. Scope* 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- 1.1 This terminology standard defines terms used in the izationestablishedintheDecisiononPrinciplesforthe description of appearance, including but not limited to color, Development of International Standards, Guides and Recom- gloss, opacity, scattering, texture, and visibility of both mate- mendations issued by the World Trade Organization Technical rials (ordinary, fluorescent, retroreflective) and light sources Barriers to Trade (TBT) Committee. (including visual display units). 1.2 It is the policy of ASTM Committee E12 on Color and 2.Referenced Documents Appearance that this terminology standard include important 2.1 ASTM Standards:3 terms and definitions explicit to the scope, whether or not the C242 Terminology of ( Ceramic Whitewares and Related terms are currently used in an ASTM standard. Terms that are Products in common use and appear in common-language dictionaries C286 Terminology Relating to Porcelain Enamel and (see Refs (1-2)) are generally not included, except when the Ceramic-Metal Systems dictionaries show multiple definitions and it seems desirable to C460 Terminology for Asbestos-Cement (Withdrawn 2001)4 indicate the definitions recommended for E12 standards. D16 Terminology for Paint, Related Coatings, Materials, and 1.3 The usage of terms describing appearance varies con- Applications D123 Terminology Relating to Textiles siderably. In some cases, different usage of a term in different D156 Test Method for Saybolt Color of Petroleum Products fields has been noted. (Saybolt Chromometer Method) D883 Terminology Relating to Plastics I This terminology is under the jurisdiction of ASTM Committee E12 on Color and Appearance and is the direct responsibility of Subcommittee E12.01 on Terminology. 3 For referenced ASTM standards, visit the ASTM website, www.astm.org, or C