A bit of a lot of things – lots of trial and error. But I settled on a process for now: Paint dot NET is my homebase.
a) Have color image.
b) Convert it to 1-bit using a little thing I found
c) Open in Inkscape
d) Control-A (Select All)
Turn off Smooth
Options: Turn off Smooth Corners
f) Path: Simplify (or Control-L) about three times
g) File: Export Bitmap.
1) Automate b) – maybe imagemagick “convert” can do it?
2) Maybe shrinking the image to like 64×64 will make thresholding work better? I don’t know.
3) Use potrace instead of Inkscape for tracing. I did and can but as I haven’t mastered potrace at all, I have to learn its options (same problem I have with Imagemagick – I don’t know it well)
4) Find another way to “simplify”. I think potrace can but I don’t know for sure.
I spent an awful long time last night breaking and fixing my Python installations (another thing I don’t know well) trying to get a “I HAVE THIS PYTHON SCRIPT THAT CAN DO INKSCAPE’S TRACING” to work. It’s a brilliant thing but I couldn’t get it to work. But, it helped me understand what was overkill and my Python is still messed up but at least two versions work again.
To confirm that that is indeed my process, I tried it as I typed it. Results aren’t identical to this morning’s so I might have skipped a step or did something differently. But I like the result just the same.
Confirms that HOW you 1-bit the information it is the crossover point between good final result and bad.