David Hockney's Sweeping Survey at the de Young SAN FRANCISCO - Although it would be hard to tell from the volume of his work, David Hockney, now 76, has had a rough year. Last October, this celebrated British artist had a stroke, which left him unable to complete his sentences for a time. In March, one of his studio assistants in East Yorkshire, part of a tight-knit circle of aides, collaborators and former lovers, died in Mr. Hockney's home after drinking drain cleaner on the heels of a drug binge. And slowly but surely, Mr. Hockney's hereditary deafness has progressed to the point that he depends heavily on two hearing aids and still needs to lean in for conversations. So it's not entirely surprising that Mr. Hockney, one of the greatest colorists since Matisse, found himself working exclusively in black and white. He stopped using his iPad as a visual diary for colorful sketches that he would circulate to the delight of friends. Even his depiction of the arrival of spring in the East Yorkshire countryside looked rather bleak, with spiky trees and their thin gray shadows rendered in charcoal instead of the lush green-and-purple palette he used for the same landscape, same season, just two years earlier. But part of Mr. Hockney's charm as a painter - and person - is a certain resilience or even insouciance, an unwillingness to abandon pleasure and beauty in the face of troubles. And his return to California this summer, after primarily living and working in England for the last eight years, has been accompanied by a return to color: not just any colors, but some of the famous cerulean and cobalt blues from his classic swimming pool paintings of the 1960s. "Los Angeles has that effect on me," said Mr. Hockney, smelling faintly of cigarette smoke and dressed in a smart gray suit with a canary-yellow shirt setting off his blue eyes. The light there is 10 times brighter than anywhere else. It's why Hollywood started there. Natural light was essential in 1910 for film. With his cane at one side and his red iPad case once again at his feet, Mr. Hockney sat in a gallery at the de Young Museum here one day recently watching the installation of his massive new survey, "David Hockney: A Bigger Exhibition." Running through Jan. 20, the show features over 300 artworks made since 2002, including some Yorkshire landscapes from his 2012 blockbuster at the Royal Academy of Arts along with other landscapes and several series of portraits. "I was always planning to come back because of the show," said Mr. Hockney, who has kept his home in the Hollywood Hills and archives and office on Santa Monica Boulevard. But it's very nice to be back in California. I'm back for a while. He was surrounded by 16 of his new vibrant portraits - all made so recently that they couldn't be included in the exhibition's catalog. "I like to think my latest work is the most interesting," he said in a throaty voice with a touch of English understatement. I'm still a reasonably lively artist, I think. The portraits were done in acrylics, a medium he began using during his first visit to Los Angeles in 1964, more than a decade before he called the city home. These days, "it feels like a new medium for me, because I haven't used it in 20 years," Mr. Hockney said. He described the intensity of working quickly with the fast-drying paint in just two or three sittings over a few days, in what the de Young's director, Colin Bailey, described as a "rush of creativity." Over the decades, Mr. Hockney has worked in depth on various series, shifting from one medium to another - from paintings to Polaroids, theatrical stage sets to intimate line drawings, watercolors to digital images on iPads - as he shuttled between the United States and England. Sarah Howgate, a curator at the National Portrait Gallery in London who wrote an essay for the San Francisco catalog, describes these shifts as fruitful. "In recent years, the making of portraits has often followed a period of large-scale activity and energy working en plein-air," she said. "The "portrait periods," involving fewer assistants, are generally calmer, more intense and introspective, perhaps, and they always take place indoors - in the studio or a domestic setting." A few of the new works, like a portrait of a Los Angeles friend, Richard Sassin, seem rather cheerful. "He told me it was the greatest day of his life, being painted by me," Mr. Hockney said, sounding amused. But most appear more somber in expression. And the first color portrait he made upon his return to California in July is a powerful expression of grief. It shows his lead studio assistant, Jean-Pierre Gonçalves de Lima, slumped in a chair with his head resting in his hands, elbows on his legs.