"Max Demian" wrote in message
o.uk...

I wonder whether people who work with colour a lot, like artists and
designers 'see' more distinct colours than the six that most (non
colour-blind) 'see', or only if they have extra words for the colours
(like teal and indigo).

It is alleged that women, on average, can determine finer differences
between near-identical colours than men. I've seen tests on web sites where
you are presented with several patches of colour, all of them identical
apart from one which is very slightly different.

I'm not sure whether the ability to see "that dress on the internet"
(https://www.independent.co.uk/news/w...-10074228.html)
as blue or gold is generally polarised men versus women. For the record, I
see it as gold and bluey-white: probably taken in the shade (which tends to
be blueish) on a camera that is set for sunlight. Given that the dress is
supposed to look like this
https://www.independent.co.uk/news/w...-10074553.html,
the photo that divided everyone is a spectacularly bad rendition of it and
I'm not surprised that so many people saw something different!

At school, when we were doing the spectrum, a colour-blind boy said he
could only see three colours. I think the teacher told him to shut up.

When I worked in a chemistry lab as a research assistant in my year off
between A levels and university, we were doing a lot of work with adding
tracers to proteins - either radioactive or colour-change. My supervisor
asked me "are you colour blind?", and when I said I wasn't, he told me about
my predecessor who kept getting different colour changes to those reported
in scientific papers. Eventually my supervisor looked over this guy's
shoulder and found that the colour changes were exactly as expected... but
the assistant was reporting them wrongly. "Oh, I'm colour blind - does it
matter?" he asked, innocently. Does it matter - just a little ;-)

Apparently the change in UK wiring colours from Red, Black, Green to Brown,
Blue, Green-and-Yellow (L, N, E) was partly for the benefit of colour blind
electricians: with most forms of colour blindness, the new colours appear
differently to each other, whereas the old colours made live and earth
appear very similar.

I remember hearing a colour blind person saying that he could not
distinguish between red and green traffic lights and had to rely entirely by
position, so he had to be extra careful at night when he couldn't see *at a
distance* whether there were two unlit lights above the one that he could
see was lit, to give context. That's partly why many (all?) traffic lights
now have a white rectangular border around the three-light head so you can
infer the position of the light that you can see.