Two friends say goodbye, and the speaker turns that moment into a strange, lovely image: they become painters, and what they paint is a set of stairs leading up into the night. The poem is only five lines long, but the picture stays with you.
The parting here doesn't feel like a slammed door. Painting is slow, patient work, and the phrase "all night" stretches the goodbye out, as if the two friends are reluctant to finish. The stairs suggest a way of climbing or leaving, but they lead into darkness, so there's a hint of uncertainty about what comes next. Still, the tone is gentle rather than sad. Parting is treated as something done with care, almost like a craft, which is what the title seems to point to.
The mood is quiet, tender, and a little dreamlike. The speaker seems to feel closeness even in separation, as though the friendship itself is what makes the stairs.