ASTM_E_1360_-_05_2015.pdf

Designation:E136005(Reapproved 2015)Standard Practice forSpecifying Color by Using the Optical Society of AmericaUniform Color Scales System1This standard is issued under the fixed designation E1360;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.INTRODUCTIONThe Optical Society ofAmerica Uniform Color Scales(OSA-UCS)were developed by a committeeof the Optical Society ofAmerica in the years between 1947 and 1974 in an effort to provide a systemand a set of samples that represent the closest possible approximation to equal visual spacing(1).2Thesystem is defined by a set of equations derived from the results of visual scaling experiments andrelated to the 1964 CIE system.The OSA sample set consisted of 558 atlas samples that fell at thelattice points of a rhombohedral close-packed arrangement within the color space defined by theequations.The unit in this spacing is a cuboctahedron,each color being surrounded by twelveequidistant nearest neighbors.See Fig.1 and Fig.2.Fig.3 shows a OSA-UCS lightness plane plottedon the CIE 1964 chromaticity diagram.The OSA-UCS system is described in Appendix X1.The system is independent of the OSA-UCS atlas samples,and other groups of samples could bechosen within the defined color space;however,for the visual determination of colors described in thisstandard,the OSA set of samples is used.1.Scope1.1 This practice provides a means for specifying the colorsof objects in terms of the Optical Society of America UniformColor Scales.Both computational and visual methods areincluded.The practice is limited to opaque objects,such aspainted surfaces,viewed in daylight by an observer havingnormal color vision.1.2 This practice does not cover the preparation of speci-mens.If the preparation of specimens is required in conjunc-tion with this practice,a mutually agreed upon procedure shallbe established.2.Referenced Documents2.1 ASTM Standards:3D1535 Practice for Specifying Color by the Munsell SystemD1729 Practice for Visual Appraisal of Colors and ColorDifferences of Diffusely-Illuminated Opaque MaterialsE284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 chromaticness,nan attribute of a visual sensationcombining hue and chroma;the visual correlate of the colori-metric quantity chomaticity.3.1.2 hue,nthe attribute of color perception by means ofwhich an object is judged to be red,yellow,green,blue,orintermediate between some adjacent pair of these.In theOSA-UCS system each hue is denoted by its angle within a360 circle beginning in the yellow direction on the right handside of the hue circle and proceeding counterclockwise throughthe greens,blues,and reds to return to the yellow hue,360,onthe+j axis.3.1.3 OSA-UCS color system,nOptical Society ofAmerica Uniform Color Scales color order system based onequality of visual spacing,which uses the lightness scale 6Land the opponent-color scales 6j(yellowness-blueness)and 6g(greenness-redness).A color in the OSA-UCS system may be1This practice is under the jurisdiction of ASTM Committee E12 on Color andAppearance and is the direct responsibility of Subcommittee E12.07 on Color OrderSystems.Current edition approved May 1,2015.Published May 2015.Originallyapproved in 1990.Last previous edition approved in 2010 as E1360 05(2010).DOI:10.1520/E1360-05R15.2The boldface numbers in parentheses refer to a list of references at the end ofthis practice.3For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 described by its L,j,g notation or by its lightness,L;hue angle,hOSA,and chroma,cOSA,designation.NOTE1The conventional terms yellowness,greenness,blueness,andredness are used throughout this practice for convenience.However,thisdoes not imply that the j and g axes indicate the locations of thecorresponding unitary hues:The+j axis closely approximates the direc-tion toward unitary yellow;but the+g axis divides the green and blueregions,the j axis divides the blue and purple regions,and the g axislocates pinks and magentas.It is probably best to think of j and g asabstract symbols unassociated with color names(4).3.1.4 OSA-UCS samples,nthe Optical Society of Ameri-cas physical exemplification of the OSA-UCS color system,which consisted of 558 samples displayed in a face-centeredlattice in three-dimensional space such that each interiorsampl