It's a complex subject. Most NTSC interlacing is what you call 3:2 interlacing. When deinterlacing this kind of interlaced content, the best method is a 3:2 p

It's a complex subject. Most NTSC interlacing is what you call 3:2 interlacing. When deinterlacing this kind of interlaced content, the best method is a 3:2 pulldown which converts the frames back to the original frames, or almost all of them, that is. There is a few frames lost in this process. Eg, 30fps interlaced then deinterlaced turns into 29.97 fps. 24 fps turns into 23.976 fps. This introduces a sort of stutter that true progressive content does not have. Also, in the 90s most anime, for example, was 24 fps, where modern day anime is 30fps or higher. This difference is noticeable as well.