This was done for a daily 30-min speedpainting group on Facebook. I used Procreate on the iPad and some custom brushes. The original painting was more square, I didn't like it as much and simply scaled it down vertically. I also used an app called PhotoForge to do an unsharp mask filter on the image similar to my process in Photoshop.
Here's the step-by-step painting capture (Procreate's new feature!) on my YouTube channel.