Well, I wish I knew this watercolor trick a few years ago! I could paint 100 pictures this way. If you're interested in the process, I followed William Stout's "Rackham" process that I found out through Justin Gerard on the AMAZING muddy colors blog. It might seem slight, but laying down a wash of colored ink over your watercolor really unifies the piece (in this case it really cooled down the orange of the kid's apollo spacesuit). I am hooked and I can't wait to try this on a more complicated piece.
Oh, and consider this the launch sketch of Jet Pack Jack's successor! Painting this spun off an entire story in my head. If you're interested in buying this astro-boy, you can do so HERE, if you'd like to buy a print you can do so HERE.
5 years ago