The painter Wayne Thiebaud died Christmas Day at the age of 101. Thiebaud had made his public debut in the early 1960s with a series of still lifes that pictured assorted dishes and desserts of the type ubiquitous in American diners and delis, and a series depicting neat rows of department-store haberdashery lit by then-new fluorescent lighting. Those still lifes are by far his best-known paintings, but they were only the beginning of a prolific decades-long career. Thiebaud’s death was met with a barrage of heartfelt tributes in the press and on social media, proving the popularity of his work among both amateurs and connoisseurs. The simplest explanation of this phenomenon is most likely the correct one: while his paintings can be appreciated for their subject matter by just about anybody, they are also sophisticated enough to keep the attention of experts.

Thiebaud’s repertoire expanded quickly. The still lifes were followed by large-scale paintings of human figures—both single- and multiple-sitter compositions. In the 1960s he also began painting mountains (something he continued to do well into the 2010s), and by the 1970s he was constructing vertiginous portraits of San Francisco streets. His 1990s quasi-aerial views of the Sacramento Delta incorporated elements of cartooning—one of Thiebaud’s lifelong passions. But according to the painter himself, the subject matter was only a pretext for solving a set of essentially formal problems that had to do with light, composition, and color.

Because Thiebaud’s first subjects came from a contemporary commercial context,