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This intercomparison contrasted scales of colour measurement of national laboratories from France, Germany, Spain and the United Kingdom. The samples used were ceramic colour standards produced by Ceram Research Ltd. These are known to be stable and uniform and have been used throughout the world for several years. The reference white standard against which the samples were measured was white opal glass with a matt surface from the BCR. The opal had been calibrated previously at NPL with measurements traceable to the PTB absolute scales of diffuse reflectance and 45 /0 radiance factor. Sets of fourteen ceramic colour standards together with a white reference opal were circulated by NPL to each of the other three laboratories. All measured values are with respect to the perfect reflecting diffuser. The report details the methods used by each laboratory and covers the three different measurement geometries: specular excluded, specular included and 0 /45 radiance factor. Expressed in terms of CIELAB units, differences between laboratories of up to +/- 1.1 units were recorded. A factor of ten improvement is required.

Additional information

Authors: VERRILL J F, National Physical Laboratory, Division of Quantum Metrology, Teddington (GB)
Bibliographic Reference: EUR 14982 EN (1993) 118 pp., MF, ECU 8
Availability: (2)
ISBN: ISBN 1 870965 12 4
Record Number: 199410150 / Last updated on: 1994-11-28
Original language: en
Available languages: en