"Time," Snape said.
"I'm finished." Hermione filled a flask with green liquid. "Are you?"
Snape glared and set down another flask. "First, effectiveness." He fed drops of potion to two white mice. They floated up an inch above the table. Snape swirled, then sniffed the flasks. "Good consistency, acceptable aroma." He smiled thinly. "However, your colour is off." Hermione's potion was a shade paler than Snape's.
"According to the Potion Matching System, Levitation Draught is colour 358." Hermione opened a swatchbook and held up a colour card. Hers matched perfectly.
So did Snape's face when she told him his forfeit.