I've been thinking of making a test that will allow us to check if pixels flicker without a need to magnify them, so every screen can be checked this way in a shop, at work, etc.

A bit of intro: After observing screens behavior (https://ledstrain.org/d/409-screens-under-microscope-in-slowmo-dithering-frc-tests/30) I noticed that they tend to alternate flickering and not flickering rows or columns. Then I thought a pattern of alternating green & black dots could reveal flicker if they do it at once. As a result I realised, that it's actually almost the same as pixel inversion patterns on Lagom site: http://www.lagom.nl/lcd-test/inversion.php#invpattern . @KM even suggested it could be polarity inversion in one of the posts.
So basically - if it was polarity inversion (not FRC / dithering) that flickers, maybe it would be easier to test the screens.

I know some of you have known good setups that don't cause issues like @JTL 's Macbook with AMD card and also setups that are causing quick eye strain. Could you post results of testing if any of Lagom images causes flicker on both categories? Please remember to check it in native resolution, so it doesn't look like e.g. set of rectangles, it has to be pixel perfect.

My screen shows significant flickering on 1 and 3, but also 2a, 2b and others look not 100% stable. If we gather enough data maybe there will be some correlation (like - screens with specific flicker or more flickering examples are worse).

No idea why your post got eaten by the spam filter.

Fixed now

Could anybody explain how polarity inversion works actually?

I made a test page where pixels are aligned as fields on a chess board and for some color pairs the flicker is visible, for some isn't (by the way - shades causing it aren't the same as ones flickering under microscope) . I don't exactly get why solid screen with still color doesn't reveal flickering - is it because average of brightness on two subsequent pixels is always the same (i.e. it could be 100%+0%, 70%+30%, 50%+50%, ...)?

If it's true, then this may be another source of invisible flicker. According to http://www.techmind.org/lcd/ referenced by Lagom poor manufacturing can make inversion cause bigger flickering, and what's important it may be controlled through software (configuration screen is mentioned) which means that driver / OS changes could potentially affect it.

dev