Harmony

Harmonies are traditionally highly sought after cels, as they area made differently from the traditional cel.  In the case of a harmony there is little to no paint on the cel and only lines on the acetate, and the colors are traditionally only painted on the background.  Giving the piece an overall water color effect.  Harmonies are generally done as A1Ends and are usually stills that are either panned, zoomed in on, or will just serve as a freeze frame to the end of an episode.  They are typically pivotal scenes of said episode or anime to deserve the harmony treatment.