Behind the scenes, the gallery is kept by a small cadre of conservators whose charge is not merely to preserve oil and pigment but to tend to the moods that live between frames. They clean the air, polish the glass, and, when necessary, perform rituals that look for all the world like careful dusting. These rituals involve oil, muted music, and an inventory of memories written on paper that dissolves in the bath at the end. Conservators rarely speak of their work outside the gallery; when they do, they use metaphors—gardening, bookkeeping, tending a hive. One of them once confessed, to a trusted visitor, that sometimes the paintings demand a substitution: a photograph, a regret, a promise. The conservator will accept these things into the frames like feed.