The sensitivity of the red cones appears to go up near violet (<a href="http:&#x2F;&#x2F;www.yorku.ca&#x2F;eye&#x2F;specsens.htm" rel="nofollow">http:&#x2F;&#x2F;www.yorku.ca&#x2F;eye&#x2F;specsens.htm</a>)<p>Wikipedia claims that is because of <i>&quot;a second resonancy of the red-sensitive cone cells.&quot;</i> (<a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Violet_light" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Violet_light</a>)