Every letter starts with a stick of charcoal and a big sheet of Yupo. It's a synthetic paper, which sounds more technical than it is. The charcoal sits right on the surface, so you get streaks, smudges and the odd patch where the stick skipped.

I started out with thin willow sticks. Everything came out a dusty grey and I hated it. The charcoal I use now is chunkier and much blacker, and it gets absolutely everywhere. My hands, the floor, the dog.

Each letter is drawn big and fast. If it goes wrong I start again on a fresh sheet, which happens more than I'd like to admit. The rougher ones tend to be my favourites, like the A and the N, because you can see exactly how my arm moved.

Once a letter's done it gets scanned at full size. I clear the dust specks and leave everything else alone. The wobbles stay.

Then it's printed to order in the UK on heavyweight matte fine art paper, so the blacks stay juicy. It arrives rolled, so give it a day under something heavy before you frame it.