The sky began to tilt,
a shift of light toward the higher clouds,
so I seized my brush
and dipped my little cup in the stream,
but once again I streaked the paper gray
with a hint of green,
water began to slide down the page,
rivulets looking for a river.
And again, I was too late-
then the sky made another turn,
this time as if to face a mirror
held in the arm of an outstretched god.
As always, the thing I am most struck by with Billy Collins is the way in which he controls tone and pacing. A poem that is as seemingly carefree and light, free-flowing as the clouds in a sun-dappled sky, actually has extremely tight control over its pace, tense, and tone.
We are greeted with a narrator who presumably, is watching the clouds, looking for inspiration to paint. The title, notably, is active. It's an activity. "Watercoloring." The narrator intends to watercolor, not merely to paint. The language is wet and active, mutable. At the start of the poem, the sky is tilting, so the narrator acts decisively. The brush was "seized" rather than picked up. The last line of the first stanza gives the impression of dipping the brush in the cup to mix colors, but carefully, Collins notes that the "cup" is dipped into the "stream", reinforcing the notion of moving water and color.
"Once again" the paper is streaked gray. The narrator has done this before, presumably to little success, given the dissatisfaction expressed in the third stanza. When the page is marked, it is not painted, but "streaked" and water, not color, "slides" down the page. Watercoloring is an activity, and the language of the poem mimics the action of the word. Watercoloring the canvas, water running into rivulets seeking a river, a cup dipped in a stream. The language flows, effortlessly, but that tone is established in the tight diction and pacing words Collins uses.
The tone shift comes at the end, as it often does with Collins. "Again" the narrator was "too late" which we can assume means a failure to capture the majesty of shifting clouds and sunset. The only adequate comparison the narrator can come up with is a god, admiring his or her own majesty in a handmirror. The tone goes from jovial, playfully introspective, to suddenly grand and majestic, much as clouds at sunset, despite being completely mundane, fascinate us without fail, and capture out imaginations and artistic sensibilities.