>>715206805
I worked it out by making a crt filter type thing myself piece by piece. You take your source image and make it bigger so now one single pixel is like 3x3 on your screen. You then blur it enough so that that square is more like a round blob - this is key, like, blurring is circular so if the blur size is enough, it doesn't matter that you started with a square, it's the same as if you started with a bright point. Now, just having blurred it, it will look shit. The edges of anything look like mush. So you layer on a darkening mask that represents the grille which is kind of like a grid of boxes that gives some structure back to the edges because to the eye, each box seem a solid color so a box contains either part of the cloud or part of the sky and not some inbetween mush. The trick is that these discrete 'boxes' are much smaller than the 'pixels' of the source image. There's several boxes to what would have been a pixel (but is now blurred out). Then because you don't want gritty boxes over your image you blur the overall thing and up the contrast, baking the grille away within the bloom of the pixels colors.
So you're replaced big squares with round glows that still seem to have some defined edges, but the edges aren't the edges of the squares.