ASTM_E_2970_-_15.pdf

Designation:E297015Standard Practice forSpecifying Color by the Natural Colour System(NCS)1This standard is issued under the fixed designation E2970;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.1.Scope1.1 The Natural Colour System(NCS)(see 1.7)provides acolor notation system that can be used to communicate color.This practice introduces the Natural Colour System,itsterminology,and conversion to and from CIE tristimulusvalues.1.2 The system described in this standard includes colorpercepts that appear to belong to the surface of a material,provided the surface is not perceived to be fluorescent or toexhibit directional color effects.1.3 The system does not include colors that appear to belongto translucent or luminescent objects(so-called volume colorsand luminous colors),nor does it include other visual proper-ties of the surface layer,such as gloss and texture.An NCSnotation does not describe the physical or chemical propertiesof an object.1.4 This practice also specifies the conditions for visual orinstrumental determination of the NCS notation of a colorsample,defines the relationships between psychometricallydetermined NCS notations and the corresponding CIE colorcoordinates which are to be used in this context.1.5 For the accuracy requirements associated with NCSstandards and NCS color samples,the user is referred toSwedish Standard SS 19104.The colored illustrations in thisstandard shall not be used as standard color samples in anyway.Color illustrations that are shown on screen or in printoutsmay be significantly different than the original NCS colorsamples with the same NCS Notation due to limited colorreproduction capabilities in screens and printers.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.7 AcknowledgementNCS,Natural Colour System is atrademark of the NCS Colour AB Stockholm,Sweden and isprotected by copyright().All rights re-served.Original NCS color samples are only available formNCS Colour AB or any authorized NCS distributor.Commer-cial use of the NCS System requires a license from NCS ColourAB.1.8 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E284 Terminology of AppearanceE308 Practice for Computing the Colors of Objects by Usingthe CIE SystemE1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation2.2 Swedish Standards:3SS 19100 Colour Notation systemSS 19102:2004 NCS Colour AtlasSS 19104 NCS colour samples Observation and measure-ment conditions and tolerances2.3 Other Documents:4CIE 15:2004 Colorimetry2.4 ASTM Adjuncts:Spreadsheet for NCS Notations and CIE Coordinates53.Terminology3.1 Terms and definitions in Terminology E284 are appli-cable to this practice.3.2 Definitions of Terms Specific to This Standard:3.2.1 elementary color,none of the six color percepts eachof which can be described only by reference to itself.1This 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 Dec.1,2015.Published December 2015.Originallyapproved in 2014.Last previous edition approved in 2014 as E2970 14.DOI:10.1520/E2970-15.2For 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.3Available from Swedish Standards Institute,SIS Frlag AB,SE-118 80Stockholm,Sweden,www.sis.se.4Available from U.S.National Committee of the CIE(International Commissionon Illumination)or CIE Webshop http:/ from ASTM International Headquarters.Order Adjunct No.ADJE2970S-EA.Original adjunct produced in 2014.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.1.1 DiscussionThe elementary colors,which are des-ignated with uppercase letters,are as follows:white(W),black(S),yellow(Y),red(R),blue(B),green(G).All other colorscan be described in terms of their resemblance to these six.White and black are achromatic elementary colors.Yellow,red,blue and green are chromatic elementary colors.3.2.2 elementary attribute,nthe degree of resemblance ofa color to an elementary color.3.2.2.1 DiscussionThe elementary attributes,which aredesignated by italic lowercase letters,are:whiteness(w),blackness(s),yellowness(y),redness(r),blueness(b),andgreenness(g).Whiteness and blac