Heads...(Threshold fun).

[Ofnuts]

(09-20-2018, 10:04 PM)trandoductin Wrote: ofnuts thought it was cool so i post it here too.

Ofnuts also thought you should clean-up the lines. Left to right:

• Original
  
• Color-select black, Select>To path , Select> from path, add white layer, bucket-fill. The trick is to increase the selection threshold while watching the historgram, and increase the threshold until your selection includes pixels that are in the 120-130 range, so that your selection really split the grays 50/50.
  
• Same as above, with some manual editing of the path to remove the more blatant spikes and dents
  

   

I admit that this method removes some detail around the eyes, but you can erase the eyes part of the new layer to have the previous layer see through.