Colour-to-smell synesthesia

A type of visual-olfactory or conceptual-olfactory synesthesia

This is a very uncommon type, despite often being cited as an example of synesthesia in general articles in magazines and websites that frequently begin with statements like “Some people can smell colours and taste sounds…”. However, in this case they are never backed up by interviews with such synesthetes or descriptions of real cases as they are actually very difficult to find.

From the few accounts I have been able to read and from my own experience, I’ve noticed the following patterns:

- although this type of synesthesia is highly consistent (same stimulus = same smell), it doesn’t occur every time the synesthete sees or thinks of the colour in question. This “part-time” nature actually seems to be quite typical of synesthesias with an olfactory concurrent.

-  fruity smells are relatively common.

- alternatively, they are often smells that are difficult to describe, not matching any known smells in real life.

- smells can be triggered in conjunction with tastes, and some synesthetes even have difficulty in distinguishing whether the perception is a smell or a taste.

Colour-to-taste synesthesia also exists, either coexisting together with colour-to-smell in the same synesthete, or separately.

Go to the page on colour-to-taste synesthesia

Here are some descriptions written by people with this type of synesthesia:

“I can sometimes smell them better than other times, and the smells are always something I’ve never smelled before.”

(Source: This comment on the online debate platform Reddit/Synesthesia. 2019.)

“They (the colours) usually have to be accompanied by a texture or pattern to make it happen. I sometimes smell and taste abstract art.”

(Source: These comments on the online debate platform Reddit/Synesthesia. 2020.)

“The purer the colour was and the larger the space it filled the more likely it was for me to smell it.”

(Source: Pau 365, my own  experience with colour-to-smell synesthesia which consistently occurred when I developed hyperosmia during a period of my life, greatly heightening my sense of smell)

The correspondences between colours and smells are idiosyncratic and vary according to the person in question. Here are the pairings of some synesthetes:

Dark blue = rain / Pink = Bubblicious gum, strawberry yoghurt / yellow = fruit, autumn / Light blue = clean clothes / Violet = fruit punch

(Source: Taken from this comment on the online debate platform Reddit/Synesthesia. 2020.)

Light blue = a smell of silk, dry late afternoon air / Yellow = the smell of the sun on a summer afternoon / White and also light grey = spaciousness, freedom, very neutral / Black: a dark, dry, square, low smell / Lilac = very synthetic, high, happy, like cheap yoghurt / Bright pink = like a perfume, hard to describe, roses and violets perhaps?, deliciously diagonal, a beautiful smell but strong

(Source: Pau 365, my own  experience with colour-to-smell synesthesia which consistently occurred when I developed hyperosmia during a period of my life, greatly heightening my sense of smell)

A few curiosities:

People who smell (or taste) objects after being blindfolded and “use synesthesia” to identify their colours are not synesthetes, or at least what they claim to do has nothing to do with synesthesia … for the simple reason that a person with this type of synesthesia needs to be able to perceive the colour in question (i.e. see it) before they can smell or taste it.

A few years ago, aerospace engineer Zachary Howard invented a “synesthesia mask” that lets people smell colours. It’s an interesting experiment that would be fun to try out, even though there are differences from what a colour-to-smell synesthete would actually experience!

Related types of synesthesia:

Colour-to-taste