Chromatic Scale

The chromatic scale contains all twelve pitches within an octave, each a half step apart. It's not a scale you improvise in — it's the complete inventory of available pitches in equal temperament. Understanding it means understanding the total available harmonic space. In practice, chromatic passing tones and chromatic approaches are fundamental tools in jazz and blues phrasing.

Construction

C chromatic scale (ascending, using sharps):
C  C#  D  D#  E  F  F#  G  G#  A  A#  B  C

C chromatic scale (descending, using flats):
C  B  B♭  A  A♭  G  G♭  F  E  E♭  D  D♭  C

All half steps: 12 notes, 12 half-step intervals.

Convention: use sharps when ascending, flats when descending. This makes the notation cleaner but the pitches are identical — C# and D♭ are the same note in equal temperament (enharmonic equivalents).

Chromatic Passing Tones

The chromatic scale's main practical use is as a source for passing tones — notes that fall between scale tones and create smooth, connected lines:

Diatonic line from C to E:  C D E
Chromatic version:           C C# D D# E

The chromatic version fills every half step, creating a smooth glide.

In jazz improvisation, chromatic passing tones connect chord tones. Moving from the root to the major third of C major, you might pass through C# and D# (or D♭ and E♭) as connecting notes. These aren't harmony notes — they're melodic connective tissue.

Chromatic Approach Notes

A chromatic approach is a half step below or above a target chord tone, played just before landing on it:

Target: E (major 3rd of C)
From below: E♭ → E  (chromatic approach from below)
From above: F → E   (diatonic, not chromatic, but same idea)

"Double chromatic" approach:
E♭ → F → E  (from below and above)
or
F# → F → E  (two chromatics from above)

Chromatic approach notes are a core bebop device. Charlie Parker built entire phrases around them. The tension of the chromatic half step just before the chord tone creates momentum and resolution.

Chromatic Lines in Voice Leading

In chord melody and arranging, chromatic inner voice movement connects chords smoothly. Moving an inner voice by half step from one chord to the next creates tension that resolves when the chord lands — more interesting than parallel motion or static inner voices. Ted Greene's chord melody work is full of this: melodies that move by half step, bass lines that approach chord roots chromatically, inner voices that slide.

The Twelve-Tone Technique

Schoenberg's twelve-tone (serial) technique requires that all twelve chromatic pitches appear before any is repeated, creating a non-hierarchical equality among all pitches. This is the opposite of tonal music's prioritisation of the root and leading tone. The chromatic scale as a complete inventory — rather than a resource to draw passing tones from — is the starting point of this approach to composition.