CIE-chromaticity xy-diagramm with spectral curve for 2° (1931) and 10° (1964) observer.
<a href="//commons.wikimedia.org/wiki/User:Boonekamp" title="User:Boonekamp">Boonekamp</a>
2008-02-02
<span class="int-own-work" lang="en">Own work</span>