ISO INTERNATIONAL STANDARD 6504-1 Second edition 2019-05 Paints and varnishes Determination of hiding power - Part 1: Kubelka-Munk method for white and light-coloured paints Peintures et vernis - Détermination du pouvoir masquant - Partie 1: Methode de Kubelka-Munk pour les peintures blanches et les peintures claires Reference number IS0 6504-1:2019(E) @ IS0 2019 IS0 6504-1:2019(E) COPYRIGHTPROTECTEDDOCUMENT @ IS0 2019 All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 CP 401 : Ch. de Blandonnet 8 CH-1214 Vernier, Geneva Phone: +41 22 749 01 11 Fax: +4122 749 09 47 Email: copyright@iso.org Website: www.iso.org Published in Switzerland i @ IS0 2019 - All rights reserved IS0 6504-1:2019(E) Contents Page Foreword .iv Introduction V 1 Scope. 1 2 Normative references .1 3 Terms and definitions 1 4 Principle 1 5 Kubelka-Munk equations .2 6 Apparatus and materials. 3 6.1 Substrates 3 6.1.1 Determination of RB 3 6.1.2 Determination of Rco 4 6.2 Film applicators . 4 6.3 Reflectometer. 4 6.4 Template 4 7 Limitations 4 8 Sampling. .4 9 Procedure 4 9.1 Determination of Rco 4 9.2 Determination of RB 5 9.2.1 Preparation of test films 5 9.2.2 Measurement of reflectance RB 5 9.3 Determination of film thickness 6 9.3.1 General 6 9.3.2 Method using polyester film 6 9.3.3 Method using black glass plates 6 10 Expression of results. .6 10.1 Calculation of wet film thickness 6 10.2 Calculation of hiding power. .7 11 Precision. .7 11.1 Repeatability (r) 7 11.2 Reproducibility (R) 7 12 Test report .7 Annex A (informative) Graphs for determination of St from RB and Ro for Rg = O,80 .8 Annex B (informative) Table of values of reflectivity Ro and factor α for Rg = O,80 .33 Annex C (informative) Examples of the calculation of hiding power from measurements of RB and Roo .34 Bibliography .36 @ IS0 2019 - All rights reserved iii