David Merritt is a concept artist based in Los Angeles whose clients include Disney Interactive Media Group, Disney Imagineering, BRC Imagination Arts, and The Jim Henson Company.
Both his online portfolio and his blog are primarily of his personal work though many pieces are done in what I presume is his professional style.
In addition to his digital concept art, both sites include his plein air painting in acrylic, pastel and occasionally digital.
Merritt teaches online classes in Digital Painting through the CG Master Academy.
