the first interesting effect, at 425nm, with all other lights off, i becomes clear the light isn't actually blue (which is what it looks like at first glance), it's indigoish violet
look at the "rods" line. near 425nm, it's still within a factor of 5-10 of peak sensitivity.
but the room stays black and white, not blue or violet, because it's still too dim for cones!
obviously this is impossible to take a meaningful photo of with an ordinary camera, since it's specifically utilizing the behavior of rods in the eye! you have to see it for yourself.
if you point it at a wall (hopefully not painted with a fluorescent paint), you can see its true color.
it's a deep, pure violet. a true violet, not red mixed with blue. yes, there is a significant qualitative difference. no, it probably won't look right on your camera.
it's a color you may have never seen before in your whole life.
here's a short blog post i found that covers some of the weird effects of spectral colors at the edge of perception: lightcolorvision.wordpress.com/2014/06/22/wav…
1. between 400nm to 350nm, colors actually go from violet back to blue because the red cone loses its last bit of sensitivity before the blue cone does.