If software filters are reducing total light by 50% while only affecting blue-ish tones, and that's a total light level comparable to multiple brightness steps on a Mac... tbh I think it's reducing it quite a lot. Many I see using them (myself included) don't tweak brightness when enabling it, and many (all?) systems don't adjust their brightness to match the perceived change from a software filter (on my Linux machines in particular I have never seen this happen, don't know about Macs though).
Half is not a lot, sure, but their ultimate suggestion is to do the same ~half change:
>You can decrease the amount of light coming from your screen by more than half simply by dimming the screen by several notches.
which is definitely significantly more than I see people doing voluntarily in the hundreds of millions.
Do they have any evidence that people are raising system brightness to match the 50% loss from the filter? If not, it still seems like a rather significant mark in their favor. Perhaps not sufficient to meet the goals (they seem to be recommending a larger change, but aren't specific), but I see no claim that a lesser decrease in light is worse.
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Late edit: on second thought... let's go through this more rigorously. For both myself and any other readers, because I want to make sure I'm following it accurately too.
The main explicit points in this article are, in order:
- night shift does not help with sleep (the main claim)
- blue light is not special, in particular because the "[most] sensitive to blue" research is mis-quoted to mean "blue is bad", but it's actually sensitive to blue and green (seems very well supported)
- night shift reduces blue and green by about half (tested themselves)
- half of absolute is not a lot because vision and a lot of the related biology is logarithmic (100% agreed)
- halving light affects 25%-50% of melatonin levels (linked research)
- many people use Night Shift (100% agreed, and they have decent data to back it up)
- dark mode is better than night shift (>90% vs ~50%, implied leaning on the linked research earlier. agreed, seems straightforward)
- dimming your screen by several steps is the same or better than night shift (as it decreases brightness more, same reasoning as dark mode. agreed.)
That still sounds rather in favor of Night Shift. It's targeting the correct color range (NOT the pseudoscience blathering), it has a moderate affect on melatonin levels at the light level changes it creates, and it's used by a huge amount of the population.
Nowhere in there that I can see is anything to back up "Night Shift does not work". Only "it seems to be doing things right, it just isn't quite enough on its own" and "ARGH it's not just blue light STOP PROMOTING FAD PSEUDOSCIENCE". That seems... fine? Most things are not silver bullets.