Imagine you had an image using all 8bits of a float to specify the shade of a given pixel. You could distinguish between a whole 256 shades of black. Now imagine if instead you wanted to have this same image use only 1 bit per pixel - your only options are now white or black.

In doing so, you lose much of the gray information, and the image becomes near unrecognizable. But if prior to applying this filter, you add random noise to your image, the result is suddenly much closer to reality.

Random noise is one of the many patterns you can chose to use. You can get cleaner effects using other strategies.

But the more stylish ones (and the one’s most associated with comic books, print, and pixel art) often involve no more than taking a pattern, adding it to a texture, and then doing our simple “less-than” “more-than” operation: