Checkerboard is neither of those, it's a different technique, so it's logical it has its own term.

Like Nyxus says checkerboard rendering is neither, it's something else, why is it so hard to grasp that for so many people??

@Aenea: Its hard to grasp because its new. Lot of people are not keen to embrace new things. Its a little like LG "4K" tv, which in fact has 3K panel but theres diffferent matrix to represent picture. Some pixels are shared and so panel can reproduce 4K like picture, but its not 4K. But neither 3K :-)

For some people is hard to udnerstand there can be something different.

But into detail: 4k upscaling is made from source where resolution is lower than 4K. In checkerboard rendering resolution is not lower. Its similar like interlaced resolution but little bit higher level. Interlacing is doing odd and even lines in different frames, So technicaly vertical resolution is halved for each frame, but in reality even and odd lines cant be exchanged, they are not same lines, they dont cross, they complement each other so as a result we get progressive level of resolution for static pictures and little bit less quality for moving ones.

In checkerboard each missing pixel is computed from other frames so we get progeressive resolution. But quality of rendering depends on changing of scene and algorithm of computing missing pixels. In reality we get better picture than interlaced resolution. And in static scenes we have same like native 4K resolution.

Thats theory of course but it is clear, checkerboard rendering is not upsacaling neither interlaced resolution doesnt upscale to progressive. Its totally different category of processing picture than upsacling.

Taking a lower resolution source image and scaling it up to a higher resolution is by definition "upscaling", regardless of what marketing buzzwords are being used to describe it.