I picked up Oliver Sacks’ book Musicophilia at the library the other day. I remember reading several favourable reviews of it when it first came out, and thought I might like to read it, but feared it may be too scientific for my taste. However, having dipped into it over the course of an evening, I find him an engaging writer, whose numerous case studies offer some fascinating insights into music and the human brain.

The chapter which interested me the most, initially, was the one entitled ‘The Key of Clear Green: Music and Synesthesia’. I am a ‘synesthete’, and, like some of the case studies referred to in the chapter, see the musical keys as colours.

Synesthesia literally means “a fusion of the senses”, and was not, until quite recently (i.e. in the last 100-odd years), considered a physiological phenomenon. Its incidence is considered to be about one in every two thousand people, though it may be far commoner, since its “sufferers” do not regard it as a “condition” for which they should seek help from a psychologist or neurologist. It is more common in women than in men. Oliver Sacks states that musical synesthesia is “one of the most common [forms], and perhaps the most dramatic”. It is not known whether it is more common in musicians or musical people, but musicans are more likely to be aware of it.

As far as I can tell, I have always had it, and, until not that long ago, assumed that everyone else had it too. I regard it as something perfectly normal, and indeed, it came as something of a shock to discover that not everyone experienced a fusion of different senses as I do. For me, letters, numbers, days of the week and months of the year all have their own distinct colours (for e.g. two = blue, five = pink, Monday = red, Wednesday = greenish-blue, January = pale orange), while others are more obscure: murky hues and shades which almost defy description. These colour associations are unchanging and are not dependent on my mood or state of mind at the time of thinking of them.

The same is true of the musical keys, each one having its own distinct colour or ‘colour scheme’. Reading one of the case studies in Dr Sacks’ book, I was pleasantly surprised to find that one of the people who contacted him experienced colours when thinking about the musical keys in exactly the same way as I do – though his colours were different to mine, which demonstrates it is very personal. The colours are also entirely inward and are never confused with external colours: for example, if I were to put D major (bright, sky blue) against a yellow background, I would continue to see it as blue, rather than green.

Here’s a selection of my ‘personal key colours’:

Major keys

C = Brick red

D = Sky blue

E = Orange

F = Mauve

G = Greenish with black

A = Red, brighter than C

B = Greenish-blue

E flat = Orange, but softer than E

A flat = Soft red

B flat = sea green

Interestingly, the enharmonic keys do not share the same colours, for they are all distinct (just as D flat major sounds different to C sharp major!):

C sharp major = Dark red

D flat major = Soft blue-green

F sharp major = purple-pink

G flat major = pale yellow-gold

The colours of the minor keys are always related to the major keys, but tend to be softer or more diffused hues.

Baroque and classical composers’ music seems to me, for the most part, to use a simpler palette than, say, the music of Schubert, Chopin and Schumann whose complex modulations and harmonic twists make greater demands on my synesthesia.

The opening movement of Schubert’s great, final sonata, the D960 in B-flat major, is, for me, a movement in sea-green and the colours of water. I see these colours when I hear the music, and when I play it, and it sits very well with my feelings about the music: that it suggests a great river, plotting its final course towards the sea. This metaphor, however, has nothing to do with my synesthesia, for the colours I see are not metaphors: they just are! And, incidentally, my colour schemes for the other movements are II: dark red and burgundy hues; III: yellow, fresh green, blue while the Scherzo changes to cooler colours; IV: cold greens and blues with occasional red patches.

In the opening movement of Beethoven’s Op 27/2, the colours shift with the harmonies, and thus, when the music is reharmonised into E major, I see strong orange hues replacing the deep, red-blacks of C sharp minor.

The word “chromatic” has taken on a fuller meaning for me while learning Chopin’s Etude Op 10 No. 3, for the chromatic passages in augmented 4ths in the stormy middle section of the piece are a riot of almost psychedelic colour as well as sound. Sadly, my synesthesia has not helped smooth the difficult path of learning this piece, but it does make it more interesting when I practise it! And by the way, this piece is mostly orange, green and red.

I have never found my condition peculiar or disabling in any way. Indeed, it positively enhances my experience of music, offering not just aural but also visual pleasures.

I would love to hear from any other musicians who experience music/sound in a similar way.

Composers who saw “key colours” include Rimsky-Korsakov, Scriabin and Messaien.