Coil coated metals. Test methods -- Metamerism
This part of ENÂ 13523 defines terms of the procedure for determining the metamerism of a colour match of an organic coating on a metallic substrate.
When two colour specimens have identical spectral reflection curves, they are matching under any illuminant irrespective of its spectral characteristics. This is termed a “spectral match?. It is also possible for two colour specimens having different spectral reflection curves to match visually under a given light source but not to match under another light source with different spectral characteristics; such matches are termed “metameric?.
One quantitative description of metamerism is the so-called “ metamerism index?.
The information of the metamerism index is of limited value where Δ E (instrumental colour difference for a given illuminant, see EN 13523-3 ) is > 0,5. The metamerism index is not suited for determining the absolute colour difference or colour constancy of a given specimen at change of illuminant.
The colour difference under the reference illuminant is to be measured in colour coordinates L*, a* and b* (see EN 13523-3 ).
Excluded from this method are organic coatings producing fluorescence and/or which are multicoloured, pearlescent or metallic.
| SDO | BSI: British Standards Institution |
| Document Number | EN 13523-15 |
| Publication Date | July 31, 2015 |
| Language | en - English |
| Page Count | 14 |
| Revision Level | |
| Supercedes | |
| Committee | STI/21 |