Grapheme-colour synesthesia

Another less-used name is “colour-graphemic” synesthesia

It includes letter-colour, word-colour and number-colour (digit-colour)


People with this type of synesthesia involuntarily associate letters, words and/or numbers with certain colours. They perceive these associated colours when reading the letters, words or numbers or thinking about them.

It is one of the most common types of synesthesia. In fact, it can probably be considered the most common of all, as it is estimated that more than 60% of synesthetes have this type. It has also been extensively studied and is very well-known, as in addition to being common (and therefore relatively easy to find subjects of study) it is highly consistent and invariable and quite easy to verify by online testing.

Despite being one of the commonest and best-known types of synesthesia, it does not fit in with the definition that synesthesia is “a crossing of the senses”, which was popular at one time but has clearly been superseded by more up-to-date definitions. Like many other types, grapheme-colour does not involve perceptions in two different senses but is a conceptual type of synesthesia, where the concept of the letters or numbers triggers a visual perception of colour.

How are the colours of the letters and numbers perceived?

Some synesthetes, who are called projector synesthetes, actually see the colours physically as if they were real. So, if they look at a page of text, they perceive the colours to be floating in space over each letter or word or the words seem to be written in ink of that colour rather than in black. Projectors account for about 10% of synesthetes. The others are called associators and see their photisms in the mind’s eye. These may take the form of a block or blob of colour or the colouring of the letter or number symbol itself, or they might simply be an association: the synesthete “knows” that the number, letter or word is that colour but doesn’t see anything visual at all, not even in their mind’s eye.
How projectors and associators perceive letters, numbers or words.
(from The Illustrated Synaesthetic Experience Questionnaire (ISEQ); Skelton, Ludwig, & Mohr, 2009, a questionnaire to determine whether grapheme-colour synesthetes are projectors or associators.) The first and second girls would be projectors and the rest associators. 

How are whole words and multi-digit numbers perceived?

When someone with this type of synesthesia reads or thinks about a word they might see each individual letter in its corresponding colour, but few grapheme-colour synesthetes actually perceive words in this way. It appears to be much more common for the whole word to take on the colour of its initial letter, as the first letter has a more forceful presence in the word. Alternatively, the word might take on the colour of its first letter but be nuanced by the tones of one or more of the letters following it. It can also happen that one of the other letters in the word bears a particular weight for the synesthete in question, even though it is not the first letter, meaning it will “colour” the whole of the word in general. This is often the case for vowels.

For numbers, the situation is often similar: if the digit 2 is blue, for example, the compound numbers starting with 2 – 24, 250, 2000 and so on – frequently also appear as blue or some variant of it. However, for some people it is the last digit that determines the colour of compound numbers, and in other cases each number has its own unique colour even if it has two or more digits.

Is there any consensus about the colour of specific letters and numbers?

In general, no: letters and numbers can be any colour at all and it can safely be said that no two synesthetes have the exact same colours for their entire alphabet or number system. However, it is true that some colours seem to be more “popular” for certain letters and numbers. The letter ‘A’ being red is the best known case perhaps (in a study conducted in 2004, researcher Sean Day discovered that A is this colour for 44% of grapheme-colour synesthetes). White ‘I’ and black ‘Z’ also occur more frequently than dictated by chance, for example. As to numbers, ‘1’ often tends to be white and zero either transparent, colourless or with no association, although there is little consensus for the rest.

The most common colours experienced by English speaking synesthetes, as shown on Sussex University’s "Synaesthesia Research" website. 

Approximate percentages of colours for the grapheme ‘T’ (from the study Trends in synesthetically colored graphemes and phonemes by Sean Day, 2004)

Emotional importance

People with this type of synesthesia tend to feel annoyed or uncomfortable when they see the symbols represented in colours different from their own. So, for example, if C is apple green for one synesthete a C written in that colour will look harmonious and “right” while a C that is blue, red or any other colour will usually give them the unpleasant sensation that it is “wrong”.


This refers to spoken words, i.e. words that are heard rather than read. A grapheme is the smallest unit of written language (a letter), while a phoneme is the smallest unit of speech differentiating one word from another (a sound). Grapheme-colour for letters and phoneme-colour synesthesia are similar, but in phoneme-colour synesthesia the colour experience on seeing the letters is related to how they sound in a word rather than just their written form.

Go to the page on phoneme-colour synesthesia

Lexeme-colour and morpheme-colour

People with this variety have colour associations for the different parts of the word: the lexeme and the morpheme. The lexeme is the root of the word. It may be accompanied by one or morphemes, which are the part of the word that is joined to the lexeme to add grammatical meaning (tense, person, number, etc.):

MILLION    (lexeme)

MILLIONAIRE     (lexeme + morpheme)

MULTIMILLIONAIRE    (morpheme + lexeme + morpheme)

Go to the page on lexeme-colour and morpheme-colour


For some synesthetes, letters, words or numbers have not only colour but also texture and other features, or they can even automatically evoke a complete image.

Go to the page on grapheme-shape/colour/texture/image


More on NUMBERS as a synesthetic inducer

For people with grapheme-colour synesthesia, numbers can have colour associations. However, there are other types of synesthesia relating to numbers: the mathematical synesthesias. These are much less common and are more complex, involving visualisations of other mathematical concepts.

Go to the page on mathematical synesthesia

Go to the page on grapheme-shape/colour/texture/image

Go to the page on phoneme-colour synesthesia

Go to the page on lexeme-colour and morpheme-colour synesthesia

This page is about grapheme-color synesthesia

This page is about grapheme-colour synaesthesia

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