Musical Light Spectrum: Brightness and Darkness

Brightness and Darkness

Musical brightness and darkness is something that has been on my mind lately. This idea of a ‘musical light spectrum’ is really interesting. I call it a spectrum, but it’s actually cyclical and doesn’t necessarily work with absolutes. Brightness and darkness are relative ideas.

The concept of brightness and darkness in music theory is applied to chords, scales, and harmony in general.

In this article, we’ll discuss the idea of musical light: brightness and darkness!

A Quick Clarification

When talking about brightness/darkness applied to harmony, we’re not describing the timbre of an instrument (a crash cymbal is brighter than a kick drum; new acoustic guitar strings are brighter than old ones, etc.). This type of brightness has to do with the frequency spectrum rather than with musical notation.

Rather, the idea of brightness has to do with pitch sets and their relativity to root notes and other pitch sets.

Please note that the brightness of timbre is definitely a musical quality! It’s just not what we’re discussing here.


The Tool For the Job

The famous Circle of Fifths will be an invaluable tool to help understand brightness and darkness.

Here is the Circle of Fifths:

Dorian Brightness Quotient

Before we get deep into the conversation of brightness, I’ll state that on the circle of fifths, clockwise is the bright direction and counter-clockwise is the dark direction. I’ll mention this as a primer now and point it out when needed as we get further into the article 🙂


What is Musical Brightness?

A note by itself is neither bright or dark. A scale on its own is neither bright or dark either. It’s all relative. So if we do say that a scale or chord is bright, we mean that it is brighter than some other scale or chord.

Here are the basics:

  • Brighter means that notes have been raised (sharped, augmented, etc.)
  • Darker means that notes have been lowered (flatted, diminished, etc.

For example, stating that “a major chord is bright” most likely means “a major chord is brighter than a minor chord.” The third is raised in a major triad.

Rather than trying to convey exactly what it is with words, the best way to explain what brightness is is to take a musical scale or chord and either brighten it or darken it!

Musical brightness is often first explained to musicians with key modulations, otherwise known as key changes. Rather than reinventing the wheel (of fifths? bad pun…) we’ll start with exactly that.


Changing Keys

When changing/modulating keys, we are relating one pitch set (a group of notes) to another pitch set.

In western theory, we have 7 notes in a key, and each note has its own letter name (A through G with alterations). This makes it easy to see which notes have been raised or lowered when modulating from one key to another.

To illustrate, let’s modulate from the key of C Major to key of G Major. 

C Major gives us this pitch set:

C       D       E        F        G        A        B        C

Whereas G Major  gives us this pitch set:

G        A        B       C        D       E        F♯

There’s a difference of one raised scale degree (F in C Major becomes F♯ in G Major). Therefore, we can say that G Major is brighter than C Major. And, therefore, that C Major is darker than G Major.

Notice that G is one fifth brighter than C (clockwise).

Brightness and Darkness

In the above Circle of Fifths diagram, the number of sharps and flats in each key are shown. This provides another visual component for us to see the bright and dark directions.

Using the above Circle of Fifths, we can state things like:

  • G Major is 1 degree brighter than C Major
  • A Major is 3 degrees brighter than C Major
  • B♭Major is 2 degrees darker than C Major
  • G♭Major is 2 degrees darker than A♭Major
  • F♯Major is 4 degrees brighter than D Major

Let’s look at the degrees of C Major against those of A Major:

Brightness and Darkness

So around the circle of fifths, A Major has its root in a clockwise position from C. And A Major has more notes in general that are in a clockwise position compared to C Major. 3 notes, to be exact, just as we stated earlier!

Looking at these two circles gives us a good visual idea that A Major is brighter than C Major, but it raises a good question, what if we related C Major to F♯Major? Would it be brighter or darker?

The Equal Luminosity Tritone Modulation

Ha, I just wanted a ridiculous name for that.

Modulating from C Major to F♯ Major or its enharmonic equivalent G♭Major brings us halfway across the circle of fifths. This key change is noted by a difference of 6 sharps (C Major to F♯ Major) or 6 flats (C Major to G♭Major).

So this modulation is much darker and much brighter at the same time. That, or we could argue that this modulation is neither bright or dark, but simply different.

The two keys are only related by two enharmonic notes (B and F according to C Major). Since so many notes have changed between the pitch sets, it’s tough to hear a shift in brightness or in darkness. I hear it as a drastic change in harmony. And I see it as an equally drastic change to brightness as it is to darkness.

Personally, I don’t truly hear the brightness in a 5-degree shift clockwise around the circle of fifths or the darkness in a 5-degree shift counter-clockwise, either. There’s an obvious difference, but I can’t tell by only listening if the key has gotten brighter or darker in these instances. Perhaps my ears are just not trained enough yet!

These drastic shifts, in theory, have the effect of extreme changes in brightness, but in practice, it’s hard to hear the effect.

Practical key changes

Modulating keys by 3 degrees in either direction is about as far as I go for a brightness/darkness effect.

Modulating to a darker key helps give us a sense of resolution in music. While modulating to a brighter key helps give us a sense of openness in the sound of our music. This isn’t always the case, but is a practical idea for the use of brightness, darkness, and key modulation!

So now that we’ve talked about the relative brightness and darkness of keys, we can use it as a segue into the discussion of scales.


Brightness and Darkness in scales and Modes

Let’s begin our discussion on bright and dark scales by referring to our first C Major to G Major key modulation.

C Major gives us this pitch set starting on C:

C       D       E        F        G        A        B        C

Whereas G Major gives us this pitch set starting on C:

C        D       E        F♯    G        A        B       C

Let’s look at those pitch sets again from a modal perspective

Checking out G Major starting on C gives us G Major’s 4th mode: C Lydian.

So another way to say that G Major is brighter than C Major is in modal terms:

C Lydian (of G Major) is brighter than C Ionian (of C Major).

The Ionian mode has the scale degrees
1        2         3         4        5        6        7

The Lydian mode has the scale degrees
1        2         3     ♯4        5        6        7

So we say the C Lydian is one degree brighter than C Lydian. Or, more generally that Lydian is a brighter mode than Ionian.

Let’s have a listen,

This is the C Ionian mode
This is the C Lydian mode

This difference of the 4th degree (F and F♯) between C Ionian (C Major) and C Lydian (G Major) gives us a good idea of brightness in scales and modes.

By raising scale degrees (individual notes in a pitch set), we brighten a scale or chord. And, in the same fashion, if we lower any scale degrees, we darken the scale or chord. Remember that it’s all relative. When a scale is bright or dark, it’s in reference to another scale, or to some idea of neutrality.

So, is there a good reference for neutrality?

The Dorian Brightness Quotient

A tool I like to use is called the Dorian Brightness Quotient (DBQ). It is a number we assign to scales to relate their brightness to the Dorian mode.

Dorian is a good reference point, as it has 3 notes to either direction of its root on the circle of fifths:

Brightness and Darkness

The DBQ only applies to heptatonic scales but is still a useful tool for thinking about brightness/darkness in scales and modes.

Basically, for each raised or lowered scale degree relative to Dorian, a mode gets a +1 or -1 added to its DBQ.

Let’s look at a chart of the modes of the Major Scale from brightest to darkest that includes DBQ values:

Dorian Brightness Quotient

So we can see that Lydian is the brightest mode and that Locrian is the darkest mode, with Dorian sitting perfectly in the middle.

Modal writing in music relies heavily on establishing a root, or tonal centre. It’s this sense of “home” the root provides that also affects the brightness of the mode.

For example, F Lydian and B Locrian have the same 7 notes. The only difference in the root note. However, Lydian is very bright compared to Locrian.

Let’s look at the modes of the C Major Scale presented on the circle of fifths to better understand modal brightness and darkness.

The Modes of C Major Scale Represented on the Circle of Fifths
F Lydian (Brightest)Brightness and Darkness
C IonianBrightness and Darkness
G MixolydianBrightness and Darkness
D Dorian (Neutral)Brightness and Darkness
A AeolianBrightness and Darkness
E PhrygianBrightness and Darkness
B Locrian (Darkest)

Brightness and Darkness

Looking at these modes with the roots highlighted furthers the importance of the Circle of Fifths as a tool for determining brightness and darkness.

Notice that Lydian (the brightest mode) only has notes clockwise of its root? Or that Locrian (the darkest mode) only has notes counter-clockwise of its root? And how about Dorian, our neutral mode. It has an equal amount of notes in either direction of its root!

The Modes of the Major Scale Represented with Scale Degrees

We touched on scale degrees when we discussed the Dorian Brightness Quotient. The table, once again:

Dorian Brightness Quotient

By raising scale degrees, we make a scale brighter. And by lowering scale degrees, we make a scale darker. This is especially obvious in the Major Scale’s modes since we only change one note at a time as we move through the modes from bright to dark and dark to bright.

There’s another way of looking at brightness that I’d like to mention here that has to do with scale degrees:

Gravitational Pull to Consonant Intervals

An interesting way to think about a scale’s brightness is in how its scale degrees “pull toward” or “push away” from the root, fifth, and octave.

The three most consonant intervals are perfect unison (if you call that an interval), the octave, and the perfect fifth.

If we think of these intervals as important gravitational centres in the scale, we can grasp yet another idea of brightness.

Modes of the Major Scale can be described quite well by their 2 sets of semitone intervals. Notes involved in semitone intervals have a strong tendency of leading us from one to the other. The major 7 in the Diatonic Scale is even referred to as the “leading tone” since it leads us up to the root.

With that in mind, if a semitone in a mode “lifts” us to the fifth or the octave, that mode will sound bright. Conversely, if a semitone in a mode “drops” us to the root or the fifth, that mode will sound dark.

Examples:

  • Lydian’s ♯4 lifts us to the fifth and its 7 lifts us to the octave.
  • Phrygian’s ♭6 drops us to the fifth and its ♭2 drops us to the root.

Locrian doesn’t even have a perfect fifth. Since its fifth is diminished, it can be thought of dropping us toward the root as well. Locrian has a strong pull downward. Another reason it is the darkest mode of the Major Scale.

Another very important interval is the third. And we’ll notice that three brightest modes have a major third, while the 4 darkest modes have a minor third. The third is important since it is a triadic chord tone.

That brings us right along to discussing the brightness and darkness of chords:

Brightness and Darkness of Chords

If we take our four triads, we have another opportunity to describe brightness. From darkest to brightest, the triads are:

  • The Diminished Triad – 1   ♭3   ♭5
  • The Minor Triad            – 1   ♭3       5
  • The Major Triad             – 1       3       5
  • The Augmented Triad – 1       3   ♯5

So we can see that the closer the notes are to the root (the smaller the intervals are), the darker the triad is. This plays into the idea of the gravitational pull toward the root mentioned earlier.

Major is brighter than Minor. This is a good starting point for understanding bright and dark. These two triads are both considered consonant, and their difference in sound captures the idea of brightness and darkness and its relativity.

Have a listen,

Here is a major triad
Here is a minor triad

In my opinion, no words can describe the idea of brightness and darkness as well as listening to a major triad (brighter) followed by a minor triad (darker).


I’ll note here that darkness and brightness do not mean consonant and dissonant, as both the diminished triad and augmented triad have a dissonant sound.

Here is a diminished triad (darkest triad)
Here is an augmented triad (brightest triad)

Both these triads sound pretty dissonant to my ears. So “bright” doesn’t necessarily mean “happy” or “consonant,” when compared to “dark.”

I won’t get too into chords in term of brightness and darkness since they are much more ambiguous. This is due to the number of notes, the different voicings, the keys they belong to, and many other factors.

I presented the triads simply to give a solid idea that chords may be considered bright or dark compared to other chords.

In Closing,

The idea of brightness and darkness is an interesting one to impose upon keys, scales, and chords. This added layer of thinking can help us to better understand the theory of music and aid us in our compositional work.

Remember that the most practical application of “musical light” is that moving in a bright direction tends to open our sound, and moving in a dark direction tends to resolve our sound.

How do you apply brightness and darkness to your playing and writing?

Is there a certain key change, modal modulation, or other compositional technique you enjoy that involves brightness or darkness? Please leave a comment below, I’d love to open a conversation about this!

As always, thanks for listening and for your support,

-Art