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




"Alistair" <alistair@xxxxxxxxxxxxxxxxxxxxx> wrote in message
news:1123802211.132493.44710@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
<snip>>
> 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.

Pete.


.