Paint away with a custom paintbrush

So now that we've made a pencil to draw with, and an inking brush to ink with, it's time to get into some coloring. Or rather, some painting. I have to admit to the fact that I have a slight obsession with speed painting brushes. (If you've never seen speed paintings, you should go and look some up on the Internet right now. And if you're feeling adventurous, try a few! They're great warm-up exercises!) Let's make a brush inspired by a speed painting brush. It's going to give us lovely, soft texture that mimics traditional brush strokes. Take a look at the colored picture below, which was digitally painted entirely with the brush we're about to make. Even the linework, which was inked with the inking brush that we just made, had the transparency locked and was gone over in more subtle, softer colors with it!

Before we can start painting with our custom brush, we're going to make a custom material to use as our...