Stillness and repose lie at the epicenter of the latest of violinist Angèle Dubeau’s series of “Portrait” recordings, a celebration of that master of atmosphere, Max Richter. Richter, whose credits include the soundtracks to Waltz with Bashir and Shutter Island, writes postminimalist music—richly scored, with gently undulating rhythms, beautiful, shifting modal harmonies, and subtle electronic effects. There’s often an elegant simplicity to Richter’s music, as in the cyclical “Autumn Music 2,” but there are thrilling moments, too, as pulsating electronic drums emerge from the darkness in “The Journey, Not the Destination.”