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Old 30-07-2011, 12:30   #16
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there is an easy fix that I tested for a color blind friend a few years ago... small patches of Wratten filters affixed to glasses (red and green). I have some that I was thinking of productizing at one point... I'll dig it out (currently in the middle of a move) and see if I have enough to share with folks who need it.

Lights are easy to identify this way...

Steve
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Old 30-07-2011, 12:34   #17
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Re: Colour Blindness and Certification

sailed with a colorblind sailor for nearly a yr-- he did ok as the buoys are different shapes--yes he did require some aid in darkness as red lighted buoys are difficult to see even by those of us with intact color vision-- but we only hit the hard one time in a near year.
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Old 30-07-2011, 12:48   #18
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Re: Colour Blindness and Certification

have them memorize the sequences of numbers if its the splotch test or the lanturn test, thats the way I have seen it done ...ie. artificial means ...red and green means severe color blindness.Ive heard people say that color blindness means you only see black and white,thats silly.DVC
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Old 30-07-2011, 12:54   #19
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Re: Colour Blindness and Certification

guy i sailed with says he sees the lights, but not the colors -- the shapes delineate the kinds of markers they are-
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Old 30-07-2011, 13:53   #20
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Re: Colour Blindness and Certification

I'm red/green color deficient. I can differentiate them when they're bright, but when they're dim and/or small I can't tell green from white (or red from some other colors). I've tried all the color-vision tests that could be used to qualify me for the USGC licenses, but I just can't do it. Bummer. I didn't even realize I had this problem until I was in high school. I've been sailing since I was six years old, and I'm not going to stop now -- fortunately for me I don't need the license. All in all, I feel I'm a reasonably safe sailor, and I try to make up for my color problems by paying more attention than many sailors I've seen. Binoculars help make the lights bigger and brighter, so this helps.

I have seen, in a British sailing magazine, a set of red and green filters that can be used to help the color-blind sailor tell red from green. Don't know if they are an appropriate way to pass the RYA test though. I'm pretty sure that the USCG testing doesn't allow them.
[I see that Microship has mentioned what are probably similar filters]
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Old 30-07-2011, 14:13   #21
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Re: Colour Blindness and Certification

Of course, there's an iPhone app for that: Color Blind Aid - Augmented Reality for the colorblind
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Old 30-07-2011, 15:50   #22
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Re: Colour Blindness and Certification

I have no knowledge of optics beyond the layman level. I have learned a bit thru interest for medical purposes as referred to in my earlier post.
But we know that light, in the form of color, is only a frequency of ray.
Camera filters change these frequencies as does stage lighting.
There is a standing joke here, that if you sail westward in Bermuda's Dundonald Channel in the late afternoon, the port hand marks are casuarina green and the st/bd hand marks are sunset red. They disappear against the shoeside and oceanside background, unless you look for them thru red coated lens binocs.
City emergency vehicles are fitted with cameras that recognise red lights and change them to green.
3D glasses work on frequency rules, don't they?

How do YOU know that the shade of red you see is the same red that your crew sees?
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Old 30-07-2011, 16:13   #23
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Re: Colour Blindness and Certification

Filters don't change frequencies, they attenuate some more than others. They can do this by absorption, reflection, or a combination of these two.

Also, the emergency vehicles don't look at the color of the traffic signals. They do put out a specific infrared signal that is picked up by detectors at the intersections (these detectors look like cameras). The detectors then control the signal lights accordingly.

But yes, perceived color is a function of the frequency of the light ray. We know that we are all responding to similar wavelengths (frequencies) in a similar way, but the question of how we actually perceive these colors leads deep into psychology, metaphysics, and ultimately insanity. I'm not going risk thinking about it!
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Old 30-07-2011, 16:36   #24
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Now that is what I call a really useful app. I am going to use this in my next class. Thanks .... It may not be a complete solution but it's definitely what I am looking for.
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Old 30-07-2011, 16:36   #25
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Re: Colour Blindness and Certification

Thanks Paul,
I CMA by saying that I am a Layman.
If attenuate implies an alteration from original form, thats what I meant by change.
Having learned a bit about Lebers Congenital Amorosis and Optic Nerve Hypoplasia, I know that a color ain't necessarily the same thing to any two people.
This is just one of those subjects I find really interesting.
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Old 30-07-2011, 16:57   #26
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Re: Colour Blindness and Certification

If this is for non commercial qualifications, see no reason that they can't pass the needs of the qualification by other than color identification of various aids. After all, that's the reason that the various aids have different shapes and/or light sequencing. I would expect some accomodation would have to be made if the test is computer generated for only those with normal color vision. Commerical licensing would be another story.

If this was the USA, think the Disability Act would lay you open for a law suit which would be messy and expensive.
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Old 30-07-2011, 17:51   #27
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If this is for non commercial qualifications, see no reason that they can't pass the needs of the qualification by other than color identification of various aids. After all, that's the reason that the various aids have different shapes and/or light sequencing. I would expect some accomodation would have to be made if the test is computer generated for only those with normal color vision. Commerical licensing would be another story.

If this was the USA, think the Disability Act would lay you open for a law suit which would be messy and expensive.
Colour blindness is not classed as a disability in the UK AFAIK. But it's an interesting thought.
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Old 30-07-2011, 18:07   #28
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Re: Colour Blindness and Certification

my friend i sailed with for a near year said all reds and blues and greens were same shade of grey. proved it by buyin ga lovely lightpurple fishin g rod n reel he thought was blue. he said it was grey so had to have been blue..
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Old 30-07-2011, 23:48   #29
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Re: Colour Blindness and Certification

Surely everyone is colour blind at night, until there is enough light to stimulate the cones in the eye? I certainly have difficulty distinguishing between red and green lights until they are close, and I know I'm not colour blind as I have been regularly tested.
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Old 31-07-2011, 00:13   #30
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Re: Colour Blindness and Certification

If you cannot determine what a lit object is or it's relative heading you are obliged to give way...stay clear, no? So it's not a problem: the colour blind skipper gives way. As for collision avoidance: one should not rely on coloured side lights alone.
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