Many notations that feature a chromatic staff exhibit either a 6-6 or a 7-5 pattern in the way that they represent the 12 notes of the chromatic scale. These patterns are generally found in the lines of a notation’s staff or in its noteheads.
6-6 Pitch Pattern
A 6-6 pitch pattern visually distinguishes the two whole-tone scales (6 notes each) within the 12 notes of the chromatic scale. This regular alternating pattern gives a consistent appearance to interval relationships, scales, and chords across all the different keys. (See our tutorial Intervals in 6-6 Music Notation Systems). Here are some examples of notations with a 6-6 pattern:
7-5 Pitch Pattern
A 7-5 pitch pattern retains a visual distinction between the seven notes A B C D E F G and the other five notes that must be represented using sharp and flat signs in traditional notation. This provides continuity with traditional notation, and a correspondence with keyboard instruments that exhibit this same 7-5 pattern. Here are some examples:
The following PDF files show scales and chords in various notation systems that have a 6-6 and 7-5 pitch pattern:
Some notation systems combine both patterns:
- Leo de Vries’ Diatonic Twinline has a 7-5 notehead color and a 6-6 notehead shape.
- As shown above, John Keller’s Express Stave has a 7-5 notehead color. An alternative version also adds a subtle 6-6 pattern in its notehead shapes by varying the slant of the noteheads.
- Richard Parncutt’s 6-6 Tetragram (shown above) has a 6-6 line pattern, but it also has a subtle 7-5 pattern since the three spaces of the four-line staff are F#, G#, and A#, and the two ledger lines are C# and D#.
 The regular binary alternation of a 6-6 pattern is analogous to the distinction between odd and even numbers in mathematics. In both cases a distinction between two interlocking sequences (of notes or numbers) helps with orientation and with perceiving and measuring relative differences between terms (either notes or numbers).