[dahart]

Yes it’s a good point that LCD pixels are more square than the CRTs that were ubiquitous when Alvy Ray wrote his paper. I think I even made that point before on HN somewhere. I did mention in response to Raph that yes the ideal target depends on what the display is, and the filter choice does depend on whether it’s LCD, CRT, film, print, or something else. That said, LCD pixels are not perfect little squares, and they’re almost never uniform color. The ideal filter for LCDs might be kinda complicated, and you’d probably need three RGB-separated filters.

Conceptually, what we’re doing is low-pass filtering, rather than blurring, so I wouldn’t necessarily call filtering just “adding blur”, but in some sense those two ideas are very close to each other, so I wouldn’t call it wrong either. :P The render filtering is a convolution integral, and is slightly different than adding blur to an image without taking the pixel shape into account. Here the filter’s quality depends on taking the pixel shape into account.

You’re right about making note of the animated examples - this is because it’s easier to demonstrate aliasing when animated. The ‘false detail’ is also aliasing, and does arise because the filtering didn’t adequately filter out high frequencies, so they’ve been sampled incorrectly and lead to incorrect image reconstruction. I totally agree that if you get such aliasing false detail, it’s preferable to err (slightly) on the side of blurry, rather than sharp and wrong.