Museum audiences long admired a certain Renaissance fresco cycle for its solemn, muted palette, which critics once treated as evidence of the painter's grave temperament. A recently completed cleaning told a different story. Beneath centuries of candle soot and yellowed varnish lay colors of startling intensity: sharp greens, hot pinks, and glowing blues that no one alive had seen. Art historians who built interpretations on the frescoes' supposed gravity now face an uncomfortable reckoning. The somber mood, it turns out, belonged to the grime, not to the artist. Some scholars welcome the cleaning as a recovery of the painter's true intentions. A vocal minority objects that the restorers, in stripping the varnish, also removed glazes the artist himself had applied, so that the newly vivid surface may misrepresent the work as much as the darkened one did.