Re: OT: Colour blindness [Was: Re: "Shared" procedure division code]

"Alistair" <alistair@xxxxxxxxxxxxxxxxxxxxx> wrote in message
> I understand that there are about 6 different forms of colour blindness
> and the info I place here is relevant to the one that I suffer from
> (red/green I think).
> As fas as I know it is not a failure of the brain to distinguish
> between the signals coming from the colour receptors (rods or cones but
> which I can not remember) but a failure of the specific cells to
> distinguish between the wavelengths of light.

When you consider the TINY difference in frequency between red and green, I
think it is a miracle that any of us can see them...

> In my case I am capable
> of distinguishing between red and green colours where the colour is
> strong (eg when viewing traffic lights or flashing lights on vehicles
> from close range) but am less able to differentiate where the colours
> are subtle (olive drab as opposed to olive green) or at some
> considerable distance (flashing vehicle lights at 400 yards (metres to
> DD)). I do not see grey instead of the red or green.

So what exactly do you see? Is it just all red or all green? If you were
looking at a coloured bar with alternating red and green blocks on it, how
would it appear? Presumably, you still see the bar itself?

> As to lettering, I am amazed at the number of publishers (web and
> printed material) who choose colour combos such as lime green and pink
> for backgrounds and lettering. I have certainly encountered unreadable
> text on packages and leaflets (I could see the text, tell the colour of
> it and knew that it was lettering but was unable to read the letter
> edges and could not define the letters).

Ah, so it appears as a blur to you? But not a grey blur?
> I have a friend who is more disabled wrt colour blindness than myself.
> Britannia Music use him to proof read their brochures.

Thanks very much for this insight, Alistair. It is fascinating. I've often
wondered about what colour blind people actually 'see' but until now never
had the opportunity to ask.