Uh oh, not the "hair bandi"!
You know, it's a whole lot easier to just scribble over your drawings with a pencil than it is to add all of the tones. By hand it would take FOREVER! And Screen toning sheets are kinda expensive.
So, most people do it on the computer, but I just like paper too much, so I just scribbled. It doesn't look as nice, but it's a huge time saver and with adding the ink for some areas goes a long way to making it look better. My bottle of ink is slightly blue, so I had to fix that on the computer.