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 deciding whether to replace with #000000 or #FFFFFF, based on the user's choice.
Here's the download:
http://bit.ly/BlackWhiteOnly-PDN-Plugin20210131-7
Source code repository: https://dev.azure.com/intrepidis/_git/Intrepidis PaintDotNet Plugins
The build pipeline: https://dev.azure.com/intrepidis/Intrepidis PaintDotNet Plugins/_build?definitionId=2&_a=summary
See below for the example before and after images, and an example of the interface.