Francis Bacon. Study for a Self Portrait (Triptych), 1985-86.
It is a unique sound. A cell door has no handle, either outside or inside; it cannot be shut except by being slammed to. It is made of massive steel and concrete, about four inches thick, and every time it falls to there is a resounding crash just as though a shot has been fired. But this report dies away without an echo. Prison sounds are echo-less and bleak.