I used Quink writing ink which splits with water into blues, and even browns as well as black and grey. I didn't wet the whole paper, I started off working dry, finding the main lines, and added water to my inked brush to paint in tonal areas. I wet the paper where I wanted the ink to spill freely. This technique is an interesting mix of the deliberate and the happy accident. I only had to blot a couple of times when I'd gotton impatient and hadn't let an area dry before working adjacent.
They were all done on A4 paper, but I've cropped each one as I saw fit.