This usually means some part of the image looks like it lags when scrolling or animating. This GIF will show the effect if viewed on an OLED display. It’s reasonably subtle, but easy to spot once you know what it looks like.
@marcedwards please please PLEASE give people the choice to not use that, I will take a little bit of smear to have true black any day, dark grey looks so cheap on OLED by comparison
@stevestreza @marcedwards is it possible to have such a dark grey that it's indistinguishable from black that doesn't trigger the smearing?
@seanreilly I don’t think so. I’d love to know more, but I think it might relate to voltage change delta for the pixel. Bigger change = takes more time. Sorry for the delayed reply!
Here’s a dramatic recreation to make it obvious (and so you can see what it looks like without needing an OLED).