The piece may be performed on any recorder ranging from voice flute to alto recorder depending on the singing range of the player. However, all singing must be performed on pitch (not a different octave as written).

The piece is based on the phenomenon of "clair-obscur", a term derived from painting; Rembrandts' painting "The conspiracy of Claudius Civilis" was the source of inspiration for this composition. The sung notes and alternative fingerings represent the effect of "obscur", like a shad...