Black and White Only
This is an effect plugin that is found under the 'Adjustments' menu. It allows the user to choose a level of grey, and any pixel which is darker becomes absolute black, or otherwise pure white. So whereas the built-in "Black and White" option makes the image "Greyscale", instead this plugin renders the image only either black or white, no grey at all.
It's a bit like making the image greyscale before posterizing to just a two colour palette of RGB(0,0,0) and RGB(255,255,255). In other words, each pixel's RGB values are mean averaged to grey before deci