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  1. #1
    Join Date
    Jul 2003
    Location
    Helston,Cornwall GB
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    214

    Question LED's in navigation lights will change their color.

    I have searched for this subject without success. That is the GREEN light turning a definite BLUE ....So am asking if anyone has had this interesting problem.? I know it is to do with the spectrum composition of LED light.
    I am interested because the manufacturers of navigation lights must be well aware that this happens and anyones thoughts on it would be appreciated.
    I rectified mine very quickly by putting some Green acetate sheet inside the lens. Chris.
    c

  2. #2
    Join Date
    Jan 2005
    Location
    Me Edinburgh, boat JWD
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    4,989

    Default Re: LED's in navigation lights will change their color.

    Which bulb is this? It took a lot of R&D to produce blue (and hence white) LEDs; greens were around for a long time. Perhaps you could patent this development?

  3. #3
    Join Date
    Mar 2015
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    Isle of Eigg
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    6,747

    Default Re: LED's in navigation lights will change their color.

    Sounds a bit bizzare really, since LED colours are defined by the chemicals in them, which will not change.
    It would be very VERY interesting to see a picture of an old and new one side by side...

  4. #4
    Join Date
    Aug 2013
    Location
    SW Scotland
    Posts
    18,586

    Default Re: LED's in navigation lights will change their color.

    Quote Originally Posted by Dougal Tolan View Post
    Sounds a bit bizzare really, since LED colours are defined by the chemicals in them, which will not change.
    True, and so a single LED can only produce monochromatic light. To produce white light they generally use a blue LED with a phosphor covering which absorbs the blue light and re-emits white. Arrays of red, green and blue LEDs have also been used but I think the phosphor route is more common now. Either way you get a spectrum which is significantly different from the spectrum of an incandescent filament. Less yellow/red, basically, so when you pass it through a green filter the output is biassed towards the blue end of the green





    It would be very VERY interesting to see a picture of an old and new one side by side...
    The light from my pulpit bicolour with warm white LED installed is definitely a blue-ier green than when it had an incandescent bulb. This worries some people a lot, but since it's still definitely green I can live with it. Free Mumsnet membership for anyone who replies "but it may invalidate your insurance".
    Last edited by JumbleDuck; 03-09-17 at 10:06.
    "Seamen are always wanting to do things the proper way; and I like to do them my way."

  5. #5
    Join Date
    Mar 2011
    Location
    Ipswich
    Posts
    194

    Default Re: LED's in navigation lights will change their color.

    I seem to recall when I changed all of ours, I had to specify whether the LED was for port, starboard or stern light - they were not interchangeable. Silly question but you gave fitted the right one? Although i have no idea how the others would make a blue light.
    Two people, two cats, one dream
    http://www.Mariadz.com/

  6. #6
    Join Date
    Oct 2011
    Location
    Plymouth
    Posts
    643

    Default Re: LED's in navigation lights will change their color.

    Quote Originally Posted by JumbleDuck View Post
    True, and so a single LED can only produce monochromatic light. To produce white light they generally use a blue LED with a phosphor covering which absorbs the blue light and re-emits white. Arrays of red, green and blue LEDs have also been used but I think the phosphor route is more common now. Either way you get a spectrum which is significantly different from the spectrum of an incandescent filament. Less yellow/red, basically, so when you pass it through a green filter the output is biassed towards the blue end of the green







    The light from my pulpit bicolour with warm white LED installed is definitely a blue-ier green than when it had an incandescent bulb. This worries some people a lot, but since it's still definitely green I can live with it. Free Mumsnet membership for anyone who replies "but it may invalidate your insurance".
    The green defined in the col regs can be quite blue anyway.

  7. #7
    Join Date
    Aug 2013
    Location
    SW Scotland
    Posts
    18,586

    Default Re: LED's in navigation lights will change their color.

    Quote Originally Posted by JohnGC View Post
    The green defined in the col regs can be quite blue anyway.
    Good point. I'd guess that my bicolour has moved from (01,06) to (01,04) on that diagram ... as it appears on my screen, of course.
    "Seamen are always wanting to do things the proper way; and I like to do them my way."

  8. #8
    Join Date
    Oct 2001
    Location
    Surrey & boat in Dorset. Both have pubs
    Posts
    3,518

    Default Re: LED's in navigation lights will change their color.

    I used a sector'd LED which had green red and white LED's for the tri-light and through the coloured lens looks very good. If you have used just a warm white LED through a coloured lens then there is I believe a colour issue.

  9. #9
    Join Date
    Mar 2015
    Location
    Isle of Eigg
    Posts
    6,747

    Default Re: LED's in navigation lights will change their color.

    Quote Originally Posted by JumbleDuck View Post
    True, and so a single LED can only produce monochromatic light. To produce white light they generally use a blue LED with a phosphor covering which absorbs the blue light and re-emits white. Arrays of red, green and blue LEDs have also been used but I think the phosphor route is more common now. Either way you get a spectrum which is significantly different from the spectrum of an incandescent filament. Less yellow/red, basically, so when you pass it through a green filter the output is biassed towards the blue end of the green







    The light from my pulpit bicolour with warm white LED installed is definitely a blue-ier green than when it had an incandescent bulb. This worries some people a lot, but since it's still definitely green I can live with it. Free Mumsnet membership for anyone who replies "but it may invalidate your insurance".
    Quote Originally Posted by JohnGC View Post
    The green defined in the col regs can be quite blue anyway.
    Quote Originally Posted by JumbleDuck View Post
    Good point. I'd guess that my bicolour has moved from (01,06) to (01,04) on that diagram ... as it appears on my screen, of course.
    Thinking on.....
    LED green isnt ColRegs approved...
    Mebby the device uses a white (made by R,G, and B LEDs) and then a green filter over that (or fades each RGB separately or mixes the appropriately (by power) as designed. The symptom of "turning blue" may just be the green element kicking the bucket.

  10. #10
    Join Date
    Oct 2011
    Location
    Plymouth
    Posts
    643

    Default Re: LED's in navigation lights will change their color.

    Quote Originally Posted by Dougal Tolan View Post
    Thinking on.....
    LED green isnt ColRegs approved...
    Mebby the device uses a white (made by R,G, and B LEDs) and then a green filter over that (or fades each RGB separately or mixes the appropriately (by power) as designed. The symptom of "turning blue" may just be the green element kicking the bucket.
    Nor is any light source. What are defined are the colours.

    Some years ago, when our local library had a subscription for BSI and I was free to look at all the standards I desired (on-line) in the reference library. I went on a hunt for the navigation light colour definitions. I don't remember the exact details, but it went something like this;

    I began with a reference in the col regs to a British or Euro-Norm standard.
    That led to a chain of other standards with each one deferring the colour definition to the next. I think there where about 4.
    The final reference was back to the appendix in the col regs which defines the colours as polygons on the CIE curve (there is a table of XY co-ordinates for each colour).

    The most interesting of these is for white; it can be quite yellow which I presume allows for oil lamps.

    This was before blue was introduced for temporary wreak markers and I haven't checked since.

    To meet a standard, a manufacture of lights must ensure the light (however created) falls within the region defined for a colour. How the colour is generated isn't/wasn't defined.

    There are two caveats I remember;
    1. There is a limit to the intensity of other colours a light may emit. For filament lamps this effectively defines the quality of the filters.
    2. Light can not be electrically dimmed. No doubt because the colour shifts. (This is true of LEDs unless the dimming is done with PWM.)

    I did that around 2003, no doubt the standards have been updated since. After all, no standards writer ever says, "We don't need any more standards, that it!".
    Last edited by JohnGC; 03-09-17 at 14:25. Reason: Filters not filers

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