Definition
In chromatic harmony all twelve notes can belong to the key. Chromaticism is not necessarily modulation: often it is a way of connecting chords by moving one or more voices by semitone. In these cases the intermediate chords have no function of their own: they are the result of the voices' movement, and should be analyzed as chromatic passing chords or neighbor chords.
Three sources of chromaticism
- Functional chromaticism: secondary dominants, secondary leading-tone chords, the Neapolitan sixth, augmented sixths. Each chromatic chord has a precise function in the key.
- Modal interchange: chords borrowed from the parallel key (iv, bVI, bVII in major).
- Linear chromaticism: the voices slide by semitone and create “passing” chords that may even have no function.
The lament bass
The descending chromatic tetrachord from tonic to dominant (in D minor: D–C#–C–B–Bb–A) is one of the oldest figures of linear chromaticism. Over the bass, different chords form at each step (i – V6 – v6 or i/C – IV6 – iv6 – V), which matter less than the line itself. It is associated with grief and mourning.
The common-tone chord
A diminished chord (or an augmented sixth) can appear over a held note of the main chord as a chromatic embellishment: C – C/D#°7 (C–D#–F#–A) – C. The C stays, the other voices move by semitone and come back. It is called a common-tone diminished seventh chord: it tonicizes nothing, it decorates the tonic.
Spelling chromaticism
- Notes that rise are preferably written with the sharp (C–C#–D), those that fall with the flat (D–Db–C).
- When the chord that forms has a recognizable function (for example a secondary dominant), the spelling follows the chord, not the direction.
Practical rules
- Analyze the lines first, then the chords: if a voice rises or falls by semitone continuously, the intermediate chords are almost always passing chords.
- Keep at least one fixed point (a held note, a stable bass or a clear destination), otherwise the key dissolves.
- Chromaticism works best in one or two voices: too many chromatic voices at once produce a confused effect (unless intended).
- Avoid cross-relations: the semitone must stay in the same voice.
Typical mistakes
- Looking for a function for every chromatic passing chord: you end up with absurd analyses with tonicizations everywhere.
- Writing a descending line with sharps: reading and intonation become difficult.
- Making all the voices chromatic without a goal: the harmonic direction is lost.
Examples
- Purcell, Dido and Aeneas, Dido's lament: a descending chromatic ground bass over which the aria unfolds.
- Bach, Mass in B minor, “Crucifixus”: a chromatic lament bass repeated thirteen times.
- Chopin, Prelude Op. 28 No. 4: the left-hand chords descend almost always moving a single voice by semitone at a time, while the melody stays almost motionless.
- Wagner, Tristan Prelude: chromatic lines that interweave and continually postpone the resolution.
- Bach, Chromatic Fantasia and Fugue: virtuosic chromaticism, both linear and harmonic.
How to use it in composition
- For a melancholy passage, write a chromatic lament bass and choose the chords above it.
- To renew interest in a long chord, use a common-tone chord as an embellishment.
- In pads and strings, a single inner voice falling by semitone (line cliché) enriches a static progression.
Exercise
- Write a chromatic lament bass in A minor (A–G#–G–F#–F–E) and harmonize it in four voices.
- Decorate an F major chord with the common-tone diminished seventh chord.
- Analyze the first eight bars of Chopin's Prelude Op. 28 No. 4 following the individual voices.
Related topics
Chromatic voice leading between chords; Line cliché; Passing, auxiliary and neighbor diminished chords; Passacaglia and chaconne; The Tristan chord and Wagnerian chromaticism; Cross-relation.