Icelandic artist and musician Ragnar Kjartansson’s often intensely durational performance-based works manifest a rare synthesis of pathos and humor. A Lot of Sorrow is both a music video and an extended concert film, in which Brooklyn-based band The National performs its three-and-a-half minute ballad Sorrow on repeat, for six hours. The band’s music and lyrics frequently conjure notions of romantic suffering and melancholy—themes common to Kjartansson’s own emotive, theatrical work.As the hours pass and fatigue sets in, the musicians subtly alter their song; the original track is always recognizable but is also treated as elastic and expressive rather than rigid. Kjartansson sometimes appears in the role of a roadie, offering water and food to the performers throughout the concert. Multiple camera angles grant the viewer access to both the perspective of the musicians and that of the audience, as the band and the crowd feed off each other’s energy with every repetition.