Chromatic scale

A chromatic scale is a special set of twelve notes used in Western music. These notes are played within one octave, and each note is a tiny step, called a semitone, away from the next. This means that between any two notes in the chromatic scale, there is only a very small change in pitch.

When instruments are tuned in a method called 12-tone equal temperament, the chromatic scale becomes very useful. It helps musicians play in any key and gives a close match to the natural sounds we hear. The chromatic scale includes all the notes found in simpler scales, like the major and minor scales.

Instruments such as the piano are built to easily play the chromatic scale. Other instruments, like the trombone and violin, can also play notes that are between the ones on a piano, called microtones. This makes the chromatic scale a important tool for musicians to create many different kinds of music.

Definition

The chromatic scale is a special set of twelve notes in music. Each note is a very small step, called a semitone, above or below the next note. This scale includes every note you can play on a piano in one octave — both the white keys and the black keys.

Because the notes are evenly spaced, the chromatic scale can be used in many different kinds of music. It adds color and movement, and can make music feel emotional or exciting. Instruments like the piano are made so they can easily play the chromatic scale.

Notation

The chromatic scale can be written in different ways depending on whether the music is played going up or down. Usually, when playing up, we use sharps, and when playing down, we use flats. This helps musicians know exactly which notes to play.

Some notes in the chromatic scale can also be named in more than one way. For example, when going up, the notes might be called Do, Di, Re, and so on. When going down, they might be called Ti, Te, La, and others. Using numbers from 0 to 11 can also help tell these notes apart clearly.

Pitch-rational tunings

Pythagorean

Main article: Pythagorean tuning

Before the 13th century, the chromatic scale was often thought of as the Pythagorean chromatic scale. This scale uses a special tuning method, which makes the twelve notes not perfectly equal in size. Because of this, the scale does not look perfectly balanced. Over time, many other tuning methods were created that also have this same uneven quality.

Just intonation

Main article: Just intonation § Twelve-tone scale

In another tuning method called 5-limit just intonation, there is a special chromatic scale known as Ptolemy’s intense chromatic scale. This scale includes extra notes placed between certain notes, making it even more detailed. Many of the note pairs can be used in different ways because small tuning differences are adjusted out.

	C	D♭	C♯	D	E♭	D♯	E	F	G♭	F♯	G	A♭	G♯	A	B♭	A♯	B	C
Pitch ratio	1	256⁄243	2187⁄2048	9⁄8	32⁄27	19683⁄16384	81⁄64	4⁄3	1024⁄729	729⁄512	3⁄2	128⁄81	6561⁄4096	27⁄16	16⁄9	59049⁄32768	243⁄128	2
Cents	0	90.2	113.7	203.9	294.1	317.6	407.8	498	588.3	611.7	702	792.2	815.6	905.9	996.1	1019.6	1109.8	1200

	C	C♯	D♭	D	D♯	E♭	E	E♯/F♭	F	F♯	G♭	G	G♯	A♭	A	A♯	B♭	B	B♯/C♭	C
Pitch ratio	1	25⁄24	16⁄15	9⁄8	75⁄64	6⁄5	5⁄4	32⁄25	4⁄3	25⁄18	36⁄25	3⁄2	25⁄16	8⁄5	5⁄3	125⁄72	9⁄5	15⁄8	48⁄25	2
Cents	0	70.7	111.7	203.9	274.6	315.6	386.3	427.4	498	568.7	631.3	702	772.6	813.7	884.4	955	1017.6	1088.3	1129.3	1200

Non-Western cultures

The ancient Chinese chromatic scale is called _Shí-èr-lǜ. It is important to know that this series of twelve notes, known as the twelve lü, were basic notes used to build different scales, not a scale by itself. In Western music, the chromatic scale is also a collection of basic notes from which other scales can be made.