Chromatic alteration

In jazz harmony, chromatic alteration is either the addition of notes not in the scale or expansion of a [chord] progression by adding extra non-diatonic chords. For example, "A C major scale with an added D♯ note, for instance, is a chromatically altered scale" while, "one bar of C moving to F in the next bar can be chromatically altered by adding the ii and V of F on the second two beats of bar one". Techniques include the ii–V–I turnaround, as well as movement by half-step or minor third.