ISO INTERNATIONAL STANDARD 6271 Third edition 2015-12-01 Clear liguids Estimation of colour by the platinum-cobalt colour scale Liquides clairs - Evaluation de la couleur au moyen de I'eéchelle platine-cobalt Reference number ISO 6271:2015(E) IS02015 IS0 6271:2015(E) COPYRIGHTPROTECTEDDOCUMENT IS0 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form written permission. Permission can be requested from either ISO at the address below or ISO's member body in the country of the requester. IsOcopyrightoffice Ch. de Blandonnet 8 . CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii @ IS0 2015 - All rights reserved IS0 6271:2015(E) Contents Page Foreword ..iv 1 Scope .1 2 Normative references 3 Principle. ..1 4 Apparatus and materials. 5 Sampling. ..2 6 Procedure ..2 7 Expression of results ..2 8 Precision .2 8.1 General .2 8.2 Repeatability limit, r .2 8.3 Reproducibility limit, R .2 8.4 Bias. .3 9 Test report ..3 Annex A (normative) Platinum-cobalt colour standards ..4 Bibliography .6 @ IS0 2015 - All rights reserved iii