Chromatic Harmony
Chords built from notes that are not in the key. They sound like they should not work, and they do, because almost every one of them contains a half step that leans straight into the chord that follows. Hear the lean and the whole subject stops being a list of exceptions.
- outside the key
- always resolves
- half steps do the work
In which styles
- Classical
- Jazz
- Film music
- Musical theatre
- Pop
In short
A key gives you seven notes and the chords built on them. Chromatic harmony borrows the other five. What keeps it from sounding random is voice leading: the borrowed note nearly always sits one half step away from a note in the target chord, and your ear follows that half step gratefully. So a chromatic chord is not a wrong chord, it is a chord with a built-in arrow.
Sharper and more urgent than anything inside the key. A chromatic chord raises the stakes of the bar it is in, because the tension it creates is bigger than anything the seven ordinary chords can produce.
Where it sits in the phrase
Chromatic chords sit just before the arrival, almost never on it. The classic position is the second-to-last chord of a phrase, where the extra pull makes the landing feel earned. Used on a downbeat with nothing after it, the same chord sounds like a mistake.
Where you run into this
- A sudden major chord a half step from where you expected one
- A bass line that walks down in half steps under a held melody
- The chord just before a key change, which is usually borrowed from the key you are heading to
The types side by side
The main families are the secondary dominants, which borrow the V of a chord that is not the tonic; the borrowed chords from the parallel minor; the chromatic mediants, a third away and sharing one note; and the augmented sixth and Neapolitan chords, which are specific voicings with specific destinations. Played back to back, the family resemblance is obvious: every one of them is a half step from where it is going.