On Wed, 3 Feb 2010 17:42:23 -0800 (PST), John Dennis
wrote:

On Feb 3, 5:56*am, "Yokel" wrote:
"DW downunder" noname wrote in message

u...
|
...
|I understand the incidence of colour vision impairment is around 25% of
males
|and a low % of females, maybe 13% of the total population. Likewise, it's
|amazing how many maps are hard to read for this 13%, how many documents use
|nice red script over a beautiful verdant green tree background - even our
|local RAC has managed that one.
|

Is it as high as that? *That means you would expect two or three people in
each cricket team to be affected, but in all the time I have been at Cadnam
(over 30 years) only one person told me that they had a problem. *Trying to
pick a red cricket ball off a green pitch when both appear to be the same
colour (as I understand it, very few people see in black and white, most
colour-blind people see fewer different colours than the rest of us) must be
a challenge. *I have enough trouble and my colour vision is good (it was
tested when I joined the railway). *Perhaps many people either learn how to
deal with it (a normal red ball is a significantly darker shade than the
pitch, unless the grass has been left very lush) or they take up sports
other than cricket.

I'm red-green colour blind, and played cricket without any issues for
40 years. Seeing the red ball *moving* is easy. What was a challenge
sometimes was at practice, when fetching a ball hit into the outfield.
Once it stopped, if I took my eyes off it for any reason (often a call
from somebody else to field their ball) then I had difficulty finding
the ball.

I cannot readily see red flowers against green leaves (the poppies in
Belgium being a prime example, or the typical Australian flowering
gum) without stopping, perhaps having them pointed out to me, at which
stage, knowing what they look to my eye, I can see them easily enough
afterwards. Until next time...

Can't get a job involving safe-working on any railway - not even a
tourist (preserved) line.


I suffer from blue-green colour blindness. It is usually called
"blue-yellow", however that term is highly misleading because no-one
with the condition has much difficulty distinguishing between blue and
yellow.

There are no safety implications, thank goodness, and at work I am
able to avoid situations where it might become a problem.

"Basil Jet" wrote in message
news
DW downunder wrote:

You can get a job in railway operations as a
left-hander but not if you're standard red-green "colour-blind".

That would explain why there are so many red-green colour blind people
driving buses.

--
We are the Strasbourg. Referendum is futile.


You mean they get on a Green bus to do Red bus runs?



DW downunder

"Yokel" wrote in message
...
"DW downunder" noname wrote in message
u...
|
...
|I understand the incidence of colour vision impairment is around 25% of
males
|and a low % of females, maybe 13% of the total population. Likewise, it's
|amazing how many maps are hard to read for this 13%, how many documents
use
|nice red script over a beautiful verdant green tree background - even our
|local RAC has managed that one.
|

Is it as high as that? That means you would expect two or three people in
each cricket team to be affected, but in all the time I have been at
Cadnam
(over 30 years) only one person told me that they had a problem. Trying
to
pick a red cricket ball off a green pitch when both appear to be the same
colour (as I understand it, very few people see in black and white, most
colour-blind people see fewer different colours than the rest of us) must
be
a challenge. I have enough trouble and my colour vision is good (it was
tested when I joined the railway). Perhaps many people either learn how
to
deal with it (a normal red ball is a significantly darker shade than the
pitch, unless the grass has been left very lush) or they take up sports
other than cricket.

But if your figures are correct, then about the same proportion of the
population are affected by each "problem". I have seen somewhere that
left-handedness is also more prevalent in males although nowhere near to
the
extent as colour blindness, which is carried on the "X" chromosome so
women
have got two chances of having the genes for correct colour vision whilst
us
men only have one.

BTW there is DDA guidance on what colour combinations should be used. I
can
remember this from my time as a announcer at Southampton Central, where we
has rules as to what colour combinations we should and should not use on
display screens. Red on green is definitely a no-no and even people with
normal colour vision may struggle with this as the clash of bright colours
confuses the eye.

Unfortunately, because of the amount of information you need to get on a
map, and so the need to colour code some of it, it is much harder to avoid
problems there. But different companies use different colour schemes so
shopping around might find one which works for you.
--
- Yokel -

"Yokel" posts via a spam-trap account which is not read.



You know, the hardest part for me, apart from mistaking boundary lines for
roads, is the use of colour scales for altitude in topographical maps. I
wish there would be a combination of colour and texture to make colour
vision less of a handicap.

DW downunder

"Paul Corfield" wrote in message
...
On Tue, 2 Feb 2010 16:46:16 +0800, "DW downunder" noname wrote:

I think, Yokel, that there are more colour-blind (colour vision impaired,
or
colour-challenged) people around than southpaws (lefties, mollydookers).
You
can get a job in railway operations as a left-hander but not if you're
standard red-green "colour-blind". Haven't found a way around it, yet.

Well indeed. As a colour blind person I spectacularly failed the LT
colour blindness test but I this was not a surprise and I wasn't going
for an operational job. I have still driven trains though - albeit
under test conditions, not with passengers.

I
understand the incidence of colour vision impairment is around 25% of
males
and a low % of females, maybe 13% of the total population.

Those percentages look high to me. I don't know the numbers but the
instances of colour blindness in females is very, very low. I doubt the
overall proportion (of the population) is anywhere near 13%.

Likewise, it's
amazing how many maps are hard to read for this 13%, how many documents
use
nice red script over a beautiful verdant green tree background - even our
local RAC has managed that one.

While I can cope with the tube map without difficulty there are some
maps which are impossible to use because of poor colour choices or
excessive use of colour / cramming colours together. Complex schematic
bus maps where every route has a colour can be impossible to deal with.
I suspect the designers have no idea how unusable their end product is
for a small proportion of the population.

--
Paul C



Well, that's a fair percentage of the regulars at uk.r - already. It's
comforting in a way to know that I am not alone.

As to the numbers, I was going on data from a long time ago, and it could
have been 1:25 rather than 25% (we're not on gradient thread, are we -
checking - OK). So, sorry if my numbers were wrong.

Nonetheless, that's rather a high number. We seem to be getting similar
numbers for ADHD and autism, too. Mainly male-oriented. I wonder how much
overlap there is? Just idling thinking, really, as I'm ADHD, colour-blind
and flat-footed. That's why I don't play poker - genetically predisposed to
a lousy hand. G & bear it

DW downunder