Time is a slippery subject: as objective as an atomic clock, as subjective as waiting for water to boil. Artists figure out vastly different ways to mark time in the works on view: Rashid Johnson’s large gestural drawing of abstracted faces traces the sustained process of movement and making, a photograph documents Bay Area artist Paul Kos’s interrogation of ice melting, a poster for On Kawara’s date paintings highlights the artist’s long-running conceptual project, New Year’s prints contain hidden clues to the variable calendars of pre-twentieth-century Japan, and more.