>>1418700>>continuedANYHOW idea is to go way past your final rez and sample down to remove fuzziness. It does all depend on your app of choice too some really sharpen way too much on upscale, PSP gets a bit annoying with the haloing. Probably where a lanczos plugin or separate processing app might do better. But you really got a steep curve with those cause it is easy to make a mess of a image with the more powerful tools. Some are simple click and go UI but often do not produce much improvement. I found it all annoying and time consuming for the slight advantage.
The marisa I am attaching is a good example the stars in her eyes were very hard not to destroy. It did not help the original was really grainy and noisy. You can still see some of the banding in her hair.
Photoshop has a filter that sorta works called smart blur, but it is really a fine line of removing artifacts and blobbing out detail. There are multiple steps with this and other blur settings some use to do clean up but I do not know them that well. Or use expensive plugins. I used to use this filter to rip out moire from scanning magazines. It does a excellent job of evening out blotchy tonal values you get from moire. You could see it in the shadows of that one MOF image I had issues with earlier, Sanae's face is really blotchy as well as anything dark blue. Dark blues always get this white bleh all over them from scanning.
In the end though. You really want to avoid upscale if at all possible. Issue is not many images or source exists for 1920 and up. SO your kinda stuck with it. A lot of artists as well only release lower rez images now to avoid being exploited by those shit wallpaper websites who charge or make $$$ off ad revenue. I am sure Im getting hosed and having some turd earning income off my hours but hey as long as a few anon enjoy the walls it is time well spent.
NOW that was a wall of text!!