This time, I brought video. It took ages to upload, but here we go.
Sorry for the poor video quality, but the good capture program was $300.
This is real time video of me doing the rendering on the Batgirl piece, using a custom Photoshop brush (if anyone wants this brush, let me know). It's only just over seven minutes, because, let's face it, the full thing would be long and boring.
What you can't see there, is how I use the keyboard shortcuts to switch tools and from foreground to background color, or how delicately I use the tablet. I do not apply much pressure at all.
Anyway, you get the idea, so here's the result.