Sure, you can describe your artistic friend's newest painting as colorful. But maybe vibrant would better suggest its particularly bright hues. Or vivid. Though perhaps to your taste it's so brightly hued as to be downright garish. Or, conversely, you may appreciate such a playful harlequin display.
Dictionary Definition:
Pronounced |n(y)oōˌäns|
From root words nuer meaning "to shade" and nue meaning "cloud."
1. A slight or delicate variation or difference in expression, feeling, opinion, etc.
2. A shade of color; a slight difference or variation in shade or tone.
3. A delicate gradation in musical expression.
Nuance is a fine word, I say, notwithstanding the elliptical critique of the word delivered by Paul Reiser's character Modell in the movie Diner:
"You know what word I'm not comfortable with? Nuance. It's not a real word. Like gesture. Gesture's a real word. With gesture you know where you stand. But nuance? I don't know. Maybe I'm wrong."