Chromatic
A chromatic scale contains all twelve notes, each a half step apart, with none "extra" or "missing" — unlike a diatonic (seven-note) or pentatonic (five-note) scale, it doesn't favor any degree over another.
A drilling tool more than a melodic one
Precisely because it ranks no note above another, the chromatic scale is rarely used to write a recognizable melody — its main use is warming up and pure velocity work, one finger per consecutive fret, without having to think about which note fits a given key.
The sheet chromatic velocity — one string illustrates exactly that use: a dexterity drill, not a composition tool.
What "chromatic" doesn't mean
"Chromatic" doesn't refer to a scale you'd use to improvise instead of the pentatonic or a diatonic scale: it's the full set of available notes, with no selection. A "chromatic passing run" in a solo is two or three connecting notes outside the current scale, not a change of scale.
Practical tips and common mistakes
- One finger per fret, no exceptions: the drill loses all its point if the pinky "skips" a note the ring finger could take — the pinky is exactly what you're trying to build up.
- Play slow and even rather than fast and choppy: the goal is equal volume and duration across all four fingers, not speed. Speed comes later, on its own.
- Sync both hands: every fretted note must land exactly with the pick attack. A left-hand / right-hand mismatch is the number-one cause of a "sloppy" sound.
- Don't make it an end in itself: a few minutes of chromatic warm-up is enough before moving to real musical content — it's not a drill to play for half an hour.