this is from Aristotle's Περί Χρωμάτων (De Coloribus):
"δῆλον δ᾽ ἐπὶ τῆς τέφρας τοῦτ᾽ ἐστίν· ἐκκαυθέντος γὰρ τοῦ τὴν βαφὴν πεποιηκότος ὑγροῦ λευκὴ γίνεται... "
Loveday and Forster translate as follows: "...ashes turn white when the moisture that tinged them is burnt out."
But is it possible that υγρού λευκή means "white like water", so that the quoted text would read "...ashes turn white like water when burned?" In the paragraph before this, Aristotle refers to water as being white (λευκόν).