Best way to select pen from old drawing

[eepjr24]

(02-15-2021, 02:36 AM)jediguitar101@yahoo.com Wrote: I've got an old Dungeons and Dragons map from I was a kid and I'm trying to remove the drawing/pen (which is black/grey at varying degrees) from the off-white/blue-grid-graph-paper that it was drawn on. What's the best way to go about this?

If you posted a snippet of the image it makes showing easier, since people can use that for examples. 

I would likely start with the select by color tool and play a bit with the Threshold to select and delete out all the blue. Then try the same with the off white. You'll likely need to be more careful with the off white as the greys from the drawing will start to get selected at some point. You can try copying the layer and multiplying it over itself to get more contrast if the original is faded.

- Ernie