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To improve sleep by reducing blue-light melatonin disruption, I wear night-glasses that filter short wavelengths (e.g. something like these). With these glasses on, both the top and bottom bars of this test image will appear visually identical:

RGB wavelength image. Bottom bar with zero blue value (Source: Personally derived from this public domain image and released to public domain)

But the colour spectrum you "see" while filtering the blue light will not appear to be either of these bars; instead some partially de-saturated hybrid of the two. I think this is probably due to a pervasive blue wavelength of the LCD back-light regardless of defined colour contrast.

However, there is something else odd going on. If I wear these glasses for several hours and then remove them for some reason - all the blue colours I should see will be muted, partially de-saturated or even interpreted as a shade of green for at least several minutes afterwards (I haven't stop-watched the effect). Freaky.


Why is this selective shift of colour perception occurring for a while after removing wavelength filtered glasses?

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I presume that, like sunglasses, when you first put on the glasses you notice a difference. If you leave the glasses on for a while, is that difference still noticeable? If you take them off for a brief moment then put them back on, does it look weird again for a bit? – Amory Oct 30 '13 at 13:31
@Amory I'd need a spare day or two to throw my sleep schedule completely out of whack to get a wider range of information. What I already know from prior use is that depending on the underlying spectral mix, blue light sources will appear green, amber or an extremely dim brown while the wearing the glasses. To be expected; but the persistent interpretation of vivid blues as a greenish-cyan or a rather muted washed-out blue for approximately several minutes after removing physical filtration is the unusual thing. I have some ideas what might cause this, but I'd be speculating. – LateralFractal Oct 30 '13 at 22:38

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