1. Scope

1.1 This practive provides numbers that correlate with visual ratings of yellowness or whiteness of white and near-white or colorless object-color specimens, viewed in daylight by an observer with normal color vision. White textiles, paints, and plastics are a few of the materials that can be described by the indices of yellowness or whiteness calculated by this practice.

1.2 For a complete analysis of object colors, by a specified observer and under a specified illuminant, use of three parameters is required. For near-white specimens, however, it is often useful to calculate single-number scales of yellowness or whiteness. This practice provides recommended equations for such scales and discusses their derivations and uses, and limits to their applicability (see also Ref ( 1 )).

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 the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use .

2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

ASTM Standards

D1535 Practice for Specifying Color by the Munsell System

D1729 Practice for Visual Appraisal of Colors and Color Differences of Diffusely-Illuminated Opaque Materials

D1925 Test Method for Yellowness Index of Plastics

E284 Terminology of Appearance

E308 Practice for Computing the Colors of Objects by Using the CIE System

E805 Practice for Identification of Instrumental Methods of Color or Color-Difference Measurement of Materials

E991 Practice for Color Measurement of Fluorescent Specimens Using the One-Monochromator Method

E1164 Practice for Obtaining Spectrometric Data for Object-Color Evaluation

E1247 Practice for Detecting Fluorescence in Object-Color Specimens by Spectrophotometry

E1331 Test Method for Reflectance Factor and Color by Spectrophotometry Using Hemispherical Geometry

E1345 Practice for Reducing the Effect of Variability of Color Measurement by Use of Multiple Measurements

E1347 Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry

E1348 Test Method for Transmittance and Color by Spectrophotometry Using Hemispherical Geometry

E1349 Test Method for Reflectance Factor and Color by Spectrophotometry Using Bidirectional (45:0 or 0:45) Geometry

E1360 Practice for Specifying Color by Using the Optical Society of America Uniform Color Scales System

E1499 Guide for Selection, Evaluation, and Training of Observers

E1541 Practice for Specifying and Matching Color Using the Colorcurve System

Keywords

color; colorimetric analysis; color/light; instrumental measurement; reflectance; reflectivity; whiteness indexes; yellowness indexes; Ceramic materials/applications; Color; Color--opaque materials; Colorimetric analysis; Instrumental measurement--color/light; Latex paints; Opacity/opaque materials; Paint testing; Paper; Psychophysical examination; Reflectance and reflectivity--paints/related coatings/materials; Solventborne paints/coatings; Spectral data--paints/related coatings; Spectrophotometry; Textile fabrics (general); Textile fibers; Tristimulus value; Visual examination--color; Whiteness index; Yellowness index;

ICS Code

ICS Number Code 17.180.20 (Colours and measurement of light)

DOI: 10.1520/E0313-00

ASTM International is a member of CrossRef.