Drawing at gigs in the near dark is good practice as I have to squint to see the basic details of what’s in front of me and get them down quickly before people move too much. It sharpens my instincts and improves my drawing in the light. I did a load of drawings at the launch of Rufus Mufasa’s new album, “Fur Coats From The Lion’s Den” in Cardiff earlier this week with a 6B graphite stick into my little lined notebook by Peter Pauper Press.
scribblah 
I share your sentiment. I love drawing in the dark. Even when you can’t make out what you’re doing, I think there’s a gain in creating the gesture, the strokes and shapes — it’s like drawing on the inside your brain!
That’s it exactly, Aletha. Drawing in your brain!