Twenty years ago, the San Francisco artist Mitchell Johnson began making annual painting trips to Cape Cod. He’d been invited to Chatham by a local art dealer, to produce local works for a show on landscapes. That first trip, in May 2005, came shortly after he’d seen an important exhibition on Giorgio Morandi and Josef Albers in Bologna, Italy. Under the spell of Morandi, Albers, and the Cape Cod village of North Truro, Johnson’s brushwork turned geometric. Color became architectural. Reviewing Johnson’s color-block landscapes, the American art critic Donald Kuspit wrote that the artist “seamlessly fuses abstraction and realism.” Johnson’s fifth Castle Hill exhibition traces the influence of Truro on 20 years of work. —Frankie Budworth