ISO/TR TECHNICAL REPORT 10688 First edition 2015-11-15 Paper, board and pulps Basic terms and equations for optical properties Papiers, cartons et pates - Equations et termes de base pour propriétes optiques Reference number IS0/TR 10688:2015(E) SO International Organization for Standardization ZHEJIANG INST OF STANDARDIZATION C15956617 IS02015 itted without license from IHS IS0/TR 10688:2015(E) COPYRIGHTPROTECTEDDOCUMENT IS02015,PublishedinSwitzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel.+41 22 749 0111 Fax+41227490947 [email protected] www.iso.org Intenationai br Prganization for Standardization icensee-ZHEJIANG INST OF STANDARDIzAoISQ s.5 -All rights reserved vided by IHS unde Not for Resale, 2016/3/29 06:09:59 etworking permitted without license from IHS IS0/TR 10688:2015(E) Contents Page Foreword ..iv Introduction. ..V 1 Scope. 2 Terms and definitions 2.1 Brightness .1 3 Calculations. .9 3.1 Colour appearance, tristimulus values. 3.2 Reflectance factor, Y-value, opacity, transmittance .13 3.2.1 Reflectancefactor,R .13 3.2.2 Luminous reflectance factor, Ry ..13 3.2.3 Y-value (C/2°). ..14 3.2.4 Opacity ..14 3.2.5 Transmittance from luminous reflectance factor measurements .14 3.3 Brightness.. .14 3.4 Light-scattering and light-absorption coefficients .15 3.4.1 Conditions for the Kubelka-Munk theory .15 3.4.2 Calculations of s and k .16 3.5 Chromaticity coordinates 17 3.6 Dominant wavelength .18 3.7 CIELAB colour space coordinates 18 3.8 Colour differences in CIELAB colour space 20 3.9 CIE-whiteness and Tint .21 3.9.1 CIE tint 21 3.9.2 CIE-whiteness, W 21 3.10 Fluorescence component 22 3.11 Metamerism index .23 3.12 Yellowness index. 23 Bibliography .24 iii ee=ZHEJIANG INST OF STANDARDIZATION C15956617 ithout license from IHS Not for Resale, 2016/3/29 06:09:59