Visible photons energy in electronvolts, which is proportional to the photon frequency.
<a href="https://meta.wikimedia.org/wiki/user:egg" class="extiw" title="meta:user:egg">Vojtěch Hála</a> and <a href="//commons.wikimedia.org/wiki/User:Gringer" title="User:Gringer">Gringer</a>
Based on <a href="//commons.wikimedia.org/wiki/File:Inverse_visible_spectrum.svg" title="File:Inverse visible spectrum.svg">File:Inverse visible spectrum.svg</a>