Colour of Light for Best Night Vision

[zeehag]

Originally Posted by noelex 77

Most boaters have never seen what full dark adaptation is like. Our modern world and our modern boats have too many light sources.
Next time you are on night sail away from shore lights, do me a favour Zeehag, turn off all light sources (other than your navigation lights). After 20 -30mins you will see what full dark adaptation looks like.
You can then decide if its worth taking steps to preserve night vision in the future.
If nothing else you will be amazed at the stars.

ROFL.
btdt.
only 7500 recent miles cruising under sail ....i KNOW what full dark is-- try a dark and stormy night no moon and rain.... no light ferom anything except the gps which lights up way too bright--is a white light---
and on my boat-- pacific ocean in dark moon time is BLACK out except stars. have YOU been there???

YES i DID compare, and i reported to you that which i found to be true.
maybe you forget that i AM out cruising and i am relaying my experience to you.....
of course, everyone is able to do these tests themselves--just make sure you really do it, not just talk about it. there is a lot of difference between research and doing.
i researched many many years before i left. i found after i left that much of my research was bunk. there is a huge difference between sailing in the dark in a sea and research on land--go out and do it, then see what you think--each of us is different in reactivity and nothing is written in stone.
if the light is brighter than a glow, it will, yes, damage the night vision. if is just a glow, as is my lamp, is good. each of us accommodates differently. use your own eyes to see, and use your own eyes to figger out what exactly you need in your own boat...
.i learned by DOING, and well after my research said to buy all red lights for night sailing--that was a waste of money to a degree, as i could not see well enough to find anything with the red lights.
enjoy.

[S/V Antares]

Great thread, While working with a large instrument Mfg. We designed a marine line that we backlighted with bi-color LED's. By reversing the polarity on the lighting circut you could change from Red to Green. The green was much less suseptable to flare when using NVG. In green (530nm) or red(680nm) the LED, being a single freq. appeared very soft. Adding a current limiting dimmer gave dramatic resaults.

We currently have a 12" plotter/radar in the nav station and an 8" in the cockpit. When using the radar down below you keep the cockpit unit very low so you do not loose night vision. Helps alot.

[zeehag]

the lowest setting of light on a garmin 498 is way too bright for my tastes in the bludi dark.. glares and is a white based light. actually pains me in darkmoon situations. the low yellowish glow from my interior lamp causes much less pain and doesnt require my accommodation defects to interfere with my ability to see immediately upon entering cockpit from interior.
i do not use any other lighting in boat--i refuse to have a tv and i donot suffer from usa-itis, or overuse of stuff with lights in it.
i LOVE sailing in the dark , and i love sailing iwth full moon and milky way lighting my path. i donot drive a catahuntebenalina, and i enjoy my oldie even with her electrical defects.
is too bad the manufacturers dont allow for use of non white lights in their products....

[noelex 77]

Originally Posted by zeehag

ROFL.
btdt.
only 7500 recent miles cruising under sail ....i KNOW what full dark is-- try a dark and stormy night no moon and rain.... no light ferom anything except the gps which lights up way too bright--is a white light---
and on my boat-- pacific ocean in dark moon time is BLACK out except stars. have YOU been there???

YES i DID compare, and i reported to you that which i found to be true.
maybe you forget that i AM out cruising and i am relaying my experience to you.....
of course, everyone is able to do these tests themselves--just make sure you really do it, not just talk about it. there is a lot of difference between research and doing.
i researched many many years before i left. i found after i left that much of my research was bunk. there is a huge difference between sailing in the dark in a sea and research on land--go out and do it, then see what you think--each of us is different in reactivity and nothing is written in stone.
if the light is brighter than a glow, it will, yes, damage the night vision. if is just a glow, as is my lamp, is good. each of us accommodates differently. use your own eyes to see, and use your own eyes to figger out what exactly you need in your own boat...
.i learned by DOING, and well after my research said to buy all red lights for night sailing--that was a waste of money to a degree, as i could not see well enough to find anything with the red lights.
enjoy.

I did not intend to criticize your sailing credentials. No offence was intended and accept my apologies if you felt any.
I have sailed on a lot of boats with experienced skippers and very few are set up to preserve night vision well . Things like a white GPS will not allow full dark adaptation.. If you read the numbers in the previous 15mins you will defiantly not be at full dark adaptation. Unfortunately sailing experience cannot alter the eyes physiology.

For the record, I have sailed for 20 years, the last 4 years I have been cruising full time ( at least 300 days a year). I have done many nautical miles sailing under the beautiful south pacific night sky.

[GordMay]

Originally Posted by zeehag

... I researched many many years before i left. i found after i left that much of my research was bunk.
There is a huge difference between sailing in the dark in a sea and research on land ...

Which might say more about the quality of YOUR research, than research in general.
Dark is dark. I cannot imagine what the practical difference between (dark on) land & sea might be. Of course, that may just speak to a lack of imagination, on my part.

[zeehag]

i read all the stories about how you HAVE to have ONLY red lighting in your boat at sea.
sorry, that statement is hogwash.

[sck5]

My own experience is that ruining night vision is more a function of the wattage of the bulbs than it is of the color. Having said that, the red lights seem to bother sleeping crew less than the white ones do.

[Lars_L]

If I have a very low intensity of light, it doesn’t care the colour, then it will not ruin your night vision. In that situation it’s only the rods that work (they how can’t see colour). If you have a blue-green (507 nm) colour, were the rods are most sensitive, you can have the very lowest intensity of light. But you’re blind where you have your focus.

If I go up in intensity so my cones start to work (they how can see colour) I should have red light (more than 650 nm) to best preserve may night vision. Is it possible to go up in intensity so much so I will be able to read a book without ruin my night vision?

[noelex 77]

Originally Posted by Lars_L

If I have a very low intensity of light, it doesn’t care the colour, then it will not ruin your night vision. In that situation it’s only the rods that work (they how can’t see colour). If you have a blue-green (507 nm) colour, were the rods are most sensitive, you can have the very lowest intensity of light. But you’re blind where you have your focus.

If I go up in intensity so my cones start to work (they how can see colour) I should have red light (more than 650 nm) to best preserve may night vision. Is it possible to go up in intensity so much so I will be able to read a book without ruin my night vision?

That’s a very good summary.
Just a couple of points to clarify if you are using a very low intensity blue-green light the light has to be of such low intensity that even large figures on say your depth display will not be readable. Rods cannot see detail well enough to resolve the numbers.
If you can read the numbers you are using your cones.

If you are using your cones unless you are using a red light (which your rods cannot see) you have bleached out your rods. It will take another 15mins or so until you regain their full function. This does not mean you have lost all night vision as cones can still see in lowish light levels, but you have lost your best low level night vision.


If you can set the boat up so that you can preserve your rod vision(your best low intensity vision) and still see the depth, log, basic gps info and make a cup of coffee etc you have a useful option. Very few boats can do this, so very few sailors ever sail at night having full dark adaptation and use of there rods. This is not an option you will use all, or even most of the time sailing at night. The chartplotter and radar are very useful tools and often, but not always, its worth sacrificing your rod vision to use these devices. If you turn the brightness down as low as possible on your chartplotter you will still help keep some night vision, but its very difficult to use the devices and preserve your rod function

[Chief Engineer]

From Zee "catahuntebenalina,"

good for a laff....thanx

[TeddyDiver]

Originally Posted by noelex 77

It will take another 15mins or so until you regain their full function. This does not mean you have lost all night vision as cones can still see in lowish light levels, but you have lost your best low level night vision.

Actually it will take over half an hour to do that..
Any night light that helps you see "better", what ever the colour, worsens your night vision. The dimmer the light the shorter the adaptation time, but it's allways at least ~>10min whatever light is used.
One trick thou, an eye pad...

[Trekka]

One advantage I have found to using red in the summer months is that it attracts far less bugs than other colors. And more critters are willing to keep their eyes wide open watching you and thus reveal their presence.

[Adelie]

The thing I took away from this article, Night Vision - The Red Myth, is that for reading charts when night adaptation needs to be maintained as much as possible, a dimmable white light set to the lowest level that works for the person using the light is the best.

Doing things where there is no need to distinguish colors or much detail, i.e. moving around in the cabin, then a dimmable cyan light is best (cyan aka blue-green or teal) for quickest recovery.

If you need to see detail, (charts with no color), a very deep red at extremely low intensity is best., but you will need to read the chart in peripheral vision instead of central.

[noelex 77]

Originally Posted by TeddyDiver

Actually it will take over half an hour to do that..
Any night light that helps you see "better", what ever the colour, worsens your night vision. The dimmer the light the shorter the adaptation time, but it's allways at least ~>10min whatever light is used.
One trick thou, an eye pad...

The rod / cone break occurs at about 10 mins. Full dark adaptation takes 25mins.
If you start from reasonably dark adapted cones 15 mins is about the time it takes to achieve full adaptation.
Most boats operate at a brightness level where they have reasonably dark adapted cones therefore to achieve full dark adaptation will take about 15 mins from there normal night time illumination to full dark adaptation.

Rods are very insensitive to far red illumination so if you are using dim red the time to full dark adaptation is very short.


Closing one eye or an eye patch is certainaly a useful trick.

[noelex 77]

Originally Posted by Adelie

If you need to see detail, (charts with no color), a very deep red at extremely low intensity is best., but you will need to read the chart in peripheral vision instead of central.

The idea with red illumination is to use your photopic vision without bleaching your scotopic vision. Photopic vision has good central acuity so there is no need to use peripheral vision when using red light.