I have a condition called synaesthesia - it can be where two senses 'join' so people associate sounds with colours etc. Mine is your average grapheme-colour variety so I perceive (not "see", I don't hallucinate) letters and numbers as having colours. The colour of a word is largely dictated by the colour of the initial letter.
en.wikipedia.org/wiki/Grapheme-color_synesthesia is a good link.
It's helpful in some ways - I am an excellent speller (cue Muphry's law) but a hindrance in others e.g. diagrams where letters/colours are linked in a 'key' but to me are the wrong combination.
This is a 100% genuine, fixed, testable (you could ask me what colour letters are at any age and I'd know) recognised condition.
Some people tell me that letters are whatever colour they are printed or displayed in. These letters probably appear purely black to you, because you're not special like me. In fact, I am starting to get quite annoyed when people insist they are black. It denies my experience of perceiving the beautiful colour in the world.
To fix this, people need to perceive the world as I do. I propose to request a law that it will be illegal to print any letter or number in the wrong colour. Writing a shopping list must be done with one of those clicky pens with ONLY the relevant shades of ink and you must select a new shade for each letter. Anything else is miscolouring and may cause a processing issue for me if I see it.
I understand that other synaesthetes also see the world in other colours. They are welcome to their view but need to be re-educated in their choices of colour. E is yellow, it always has been yellow and to suggest otherwise is actually quite offensive to me.
I'm glad I have your support.