This lesson is broken up into two sections. It is a very short introduction to chromaticism and a very brief discussion of colour (in the reverse order). Both subjects deal with a similar topic: "how do we make existing, well structured music more expressive and more complex. The first part addresses how to do this harmonically (vertically on the staff) while the second looks at this melodically (horizontally on the staff).

Colour

We've talked a lot about the function of chords but up until now we haven't really talked a lot about chords that aren't triads or sevenths. When we looked at chords we talked mostly about thirds. The chords we're familiar with are built on a structure that look like:

Root note
Note a third above root
Note a fifth above root (or a third above the third)

When we build a chord we start with the root note (i.e. the note name of the chord "C" major, "Bb" augmented, etc) and then stack a third on top of it and a third on top of that. Looking at C major:

G - fifth
E - third
C - root

The interval between the C and E is a major third, between C and G a perfect fifth, and between E and G a minor third.

We modify the quality (major/minor/augmented/diminished) of these intervals to form new kinds of chords. All of these chords have the same root but different thirds and fifths.

Major    Minor    Augmented    Diminished
E        E        E#            Eb
C#        C        C#            C
A        A        A            A

The quality of a chord determines it's primary colouring - the sort of mood it invokes. We can add colour to chords by stacking another third on top of the whole structure to make seventh chords. There are even more kinds of seventh chords: major, minor, diminished, dominant, major-minor, minor-major, half diminished, augmented, etc.

We can stack even more thirds on top of these chords to form ninths, elevenths, and thirteenths. We only stop there because by the time we hit a fifteenth we've already used all 7 scale degrees so stacking more thirds means repeating note names (though no one is stopping you if you want to do it). As we stack more thirds our chords become more complex and capable expressing of more advanced and specific ideas. In jazz, this is called "colouring".

Now with every note we add to a chord we change how that chord fits in with our music. In general as the number of notes in a chord increases, the number of possible types of that chords rises factorially and it becomes increasingly complex. So while it can be pretty easy to know what functional chord should come next in a progression (I, V, IV, vi, etc.) it's really tough to pinpoint what sort of colouring will sound best without experimenting.  One nice bonus of using more complex chords is that with each added note the relative importance of each note in the chord decreases. In other words, if you make more noises, we will notice the individual contribution of each sound less and focus more on the whole. Let's now discuss chromaticism which will give us some insight into how we can experiment to create new chords.

Chromaticism

Chromaticism literally means "colouring". It is built off the idea of the chromatic scale which is a scale that ascends or descends in semitones from one note to the next octave. The chromatic scale on F# would be:

F#-G-G#-A-A#-B-C-C#-D-D#-E-E#-F#

whereas the diatonic scale would be:

F#-G#-A#-B-C#-D#-E#-F#

One thing we often do with the chromatic scale is to smoothly link the notes in the diatonic scale. This happens a lot with melodies when they are rising or falling through an interval of a major second (or a whole tone). We can link the upper and lower notes by splitting the whole tone into two semitones. It's often done in minor keys to create tension associated with a dominant V chord. For example:

Without chromaticism:

| i | iv | i | V |

Am | Dm | Am | E |

with chromaticism:

| i | iv | i | v / V |

Am | Dm | Am | Em / E |

One of my favorite ways to use chromaticism is by raising the root of a major chord up a semitone to create a diminished chord. This is especially effective when you have a progression which has a chord change where the root goes up a whole tone. In that case you can link the two chords by passing through the diminished chord like:

In C major:

| G / G#dim | Am |

or

| F / F#dim | G |

Anyways, these are just a few ways to use chromaticism to enrich and smoothen your progressions. The possibilities are endless. Play around and see what you can find.

Nice one DTF
I'd encourage anyone to practice Chromatic scales and Chromatic chord progressions, it opens everything up, thus you have more chance of creating something unique, the possibilities are endless as DTF says.  It's also good to train your ears, also practice Chromatic scales on your instruments and vocally, vocally it helps you to sing in tune better.

Thanks for this DTF.

I've been very impressed with the whole series of lessons you have posted here. You have a strong, clear writing style and have managed to break down a vast subject area into some very useful easily-digested chunks. Keep up the good work!