Color Synesthesia goes something like this: When a synesthete sees a 6 printed in black ink, she knows it is black and sees it as black but she also has the experience of greeness. That experience of green is automatic and involuntary. For some, the experience is internal(Green in the mind’s eye), For others, the color may have a location (say, superimposed on the letter). Typically, it is a little disconcerting for a synesthete to view a letter in the “wrong” color – For example, looking at a red 6 when it seems to that individual that only 3 can be red.
Similiar to colored numbers are colored letters: these forms of synesthesia typically occur together and collectively are referred to as grapheme-> color synesthesia. The color associations for each grapheme differ for each synesthete and typically have very precise hues.
We earlier mentioned David Starr Jordan’s 1917 report of grapheme – Color synesthesia entitled ” The colors of letters” Source : Jordan DS 1917. The colors of letters. Science 46(1187):311-312.Jordan, a Stanford psychologist, presciently wrote,” It has been misunderstood by writers, who have imagined that the peculiar individuals having this trait actually see the color on the letter, which is not the fact. It is a mental association, not a false vision.” This description holds true today, even though a minority of grapheme -> color synesthetes do experience their color as having a particular location. Even in that case, synesthetic colors are readily distinguishable from real colors in the outside world.