I drew a random head a few days ago (top right) and today I drew into it a bit more with my home-made walnut ink (top left), not planning anything, just emptying my head of thoughts and letting my hand and the brush do their own thing. I wasn’t sure whether to carry on adding layers of ink, so I scanned it and loaded it up into Adobe Photoshop and tried out a couple of different Gradient Map options (middle right and bottom). There’s some pretty stuff going on in them.
scribblah 
I think that’s such a good way to play with art.
Yes, I tend to get obsessed with producing something “finished”, which I caution my students against, so this is a good exercise for me.