How much melanopic light
does your filter remove?

How the calculator works

The model is the same one described on our research page, simplified to three numbers. Melanopsin sensitivity is approximated as a Gaussian centered at 480nm with a standard deviation of 30nm. A typical display's primaries are approximated as Gaussians at 630nm (red), 530nm (green), and 455nm (blue). Integrating each primary against the melanopsin curve gives the share of melanopic light each channel carries: roughly 63 percent from blue, 37 percent from green, and well under 1 percent from red.

Your slider settings scale each channel. The melanopic light that remains is the weighted sum of the three channels; suppression is what got removed. Perceived brightness uses standard luminance weights, where green dominates. That contrast is the whole point of spectral filtering: because melanopic weight lives in blue and cyan while perceived brightness lives in green, a well-shaped filter can remove most melanopsin-activating light while keeping the screen usable.

Two honest limits. First, real displays differ; an OLED's primaries are narrower than an LCD's, so treat results as estimates rather than measurements. Second, melanopic suppression is a description of light, not a medical outcome. Research led by Noseda and colleagues linked ipRGC signaling to migraine photophobia, and McAdams and colleagues found amplified ipRGC responses in migraine patients, but how much filtering helps varies from person to person.

Want this computed live against real spectral curves, with dimming below minimum brightness and per-display control? That is what Nox does from your menu bar.