BS EN 13523-22:2017 pdf free.Coil coated metals-‘ Test methods.C olour difference – Visual comparison.
BS EN 13523-22 This part of the EN 13523 series specifies the procedure for determining the difference in the colour of an organic coating on a metallic substrate by visual comparison against a standard using either diffuse natural daylight or artificial daylight in a standard booth.NOTE Results might differ between natural and artificial daylight.It might be that two colour specimens will match in daylight but not under another light source. This phenomenon is known as metamerism (see EN 13523-15).If a metameric match is to be reported in objective terms, spectrophotometric measurements (using CIE Standard Illuminants D65 and A) should be made, in accordance with EN 13523-15.No statement is made about either the precision or the accuracy of this procedure since the results derived are neither in numerical form nor do they provide a pass/fail evaluation in objective terms. Therefore, this procedure should only be used where the use of colour measuring instruments is not recommendable (evaluation of colour matches, inspection of metallic colours, etc.).The standardization of such visual comparisons, by light sources, iluminating and viewing geometry and specimen size, provides for improved uniformity of results. This practice is essential for critical colour matching and is highly recommended for colour inspections.The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.EN 13523-0:201 4, Coil coated metals一Test methods一Part 0: General introduction.The colour matching booth shall be an enclosure from which external light is excluded and which is illuminated by a light source giving a spectral power distribution falling on the test specimen,approximating to that of CIE Standard lluminant D65. The interior of the booth for general use shall be painted a matt neutral grey (the amount of a* and b*shall be less than 1,0] with a lightness L* of about 45 to 55 (Munsell N4 to N5, NCS S 5500-N to S 6500-N). However, when mainly light colours and near-white colours are to be compared, the interior of the booth may be painted so as to have a lightness L* of about 65 (Munsell N6, NCS S 4500-N) or higher in order to give a lower brightness contrast with the colour to be examined. When mainly dark colours are to be compared, the interior of the booth may be painted matt black with a lightness L* of about 25(Munsell matt black, NCS S 9000-N).BS EN 13523-22 pdf download.