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Whay do so many people still choose red night lighitng?

5K views 31 replies 16 participants last post by  Omatako 
#1 · (Edited)
Why do so many people still choose red night lighitng?

Reading the LED thread I was struck by how many people still use red light, and I was just wondering what the rationale for that choice was since the scientific consensus for decades seems to be that dim white light is far superior for visual acuity and takes only slightly longer to recover night vision than red.

This is compounded by the fact that a great many of the red light solutions out there, LED or otherwise, are radiating at 600nm to 650nm, where you will get all of the drawbacks like no detail vision and central blind spot with very few benefits with regard to preserving night vision. You want nothing shorter than about 700nm if you do go with red night lights.

Considering all of that (and leaving aside the topic of cyan lighting and active light amplification devices) I have always tended toward continuously dimmable white light in environments where I will need to switch between detail-oriented reading or working and using my night vision.
 
#7 ·
Do you have an article or paper on the topic we can read?
Nothing I can reference off the top of my head, although googling does come up with some good stuff. That article sixpoint linked a few posts below yours has a ton of references at the end.

I was in high school the first time I had cause to read up on this topic (theater geek, was part of a project to re-rig the catwalks and lighting control systems), and have revisited it for various reasons a few times since then.
 
#3 ·
I wasn't aware of that either... my military and law enforcement training would suggest contrary to your statements, but I'm always open to new (even if just new to me) schools of thought.

Guess I need to research this further.

Thanks for the tip. :)

SP
 
#5 ·
The problem is that there really is no useful light source that won't destroy our night vision. If we need light to be able to see detail, then we pretty much are going to sacrifice our night vision. On the water at night, even the bit of reflected light from your stern light is going to wipe out your night vision. The rods are incredibly sensitive and are quickly and easily overloaded.

It is true that if you use a dim enough light source of a wavelength shorter than 650nm for a short enough period of time, then you can spare your night vision. The problem is that there are very, very few tasks where you need light that it will provide enough.

Being old doesn't help a bit either.

Dave

Reading the LED thread I was struck by how many people still use red light, and I was just wondering what the rationale for that choice was since the scientific consensus for decades seems to be that dim white light is far superior for visual acuity and takes only slightly longer to recover night vision than red.

This is compounded by the fact that a great many of the red light solutions out there, LED or otherwise, are radiating at 600nm to 650nm, where you will get all of the drawbacks like no detail vision and central blind spot with very few benefits with regard to preserving night vision. You want nothing shorter than about 700nm if you do go with red night lights.

Considering all of that (and leaving aside the topic of cyan lighting and active light amplification devices) I have always tended toward continuously dimmable white light in environments where I will need to switch between detail-oriented reading or working and using my night vision.
 
#6 ·
"Dim" is a relative and subjective concept, while "red" is less variable from one person to the next. And then again, too many folks have seen too many WW2 movies and "know" that night lighting MUST be red. [sic]

Myths die hard.

Ever heard that carrots are good for your night vision?
Yeah, well, that was intentional disinformation started by the British during WW2, so the Nazis would think all the carrots being fed to the Allied fighter pilots (and they did serve them!) were the reason the Nazi aircraft were being "seen" at night. The real reason was RADAR, new and top secret, and by saying carrots and night vision were the real secret...Disinformation works.

Here it is, 70+ years later and still working.
 
#9 ·
It may be a matter of chart contrast. As printed, NOAA charts for example would be more legible under red light than they are under dim white light. That and a definition of "dim white" differs. Is it dim incadescent, which is mostly yellow or dim led which is more "blue"? Few lights are actually white.

Personally, I simply like the appearance of dim red more than any other light under circumstances - it feels "warm" and more pleasant.
 
#12 ·
I'm not sure that tracks with the sort of background data we've been discussing. If you are using active devices then there are reasons not to use red ambient lighting, but in what way are you suggesting that not using active devices is a reason to prefer red ambient?
 
#11 ·
Having a light as dim as possible is the most important thing, but red is better at preserving night vision. This is not a myth. Our Scotopic (night) vision is much less sensitive to red light than our Photopic (detailed) vision. This is basic ocular physiology.

Unfortunately red light is unsuitable for some applications (you cannot see colour for example) so for some tasks, particularly military based, another colour , or mixture of colours is used. If, however, you want to optimally preserve your night vision for general tasks a red light as dim as possible(fit a dimmer and lower the brightness as you dark adapt) is the best option.
Night vision is important and once lost it will take about 20 mins to regain so its worth preserving.
 
#13 · (Edited)
In general theoretical terms I'd agree with most of that (cyan may be better than red where preserving dark adaptation is the absolute priority), but in practice people tend to run the red lights far too bright and at too short a wavelength and so they wind up much worse off all around than if they used suitably dim white light in the first place.

In regards to the other comments along the lines of "'dim' and 'white' are subjective", that is true but it doesn't really matter. "Dim" is "as dim as you can possibly make it and still do your job" and "white" can be anything from very warm to very cool without it making much difference.
 
#20 ·
"As printed, NOAA charts for example would be more legible under red light "
Except for the magenta lines that disappear because they are too close to red.
As "the red myth" link says, "Unfortunately there are a number of drawbacks using only night vision."

But instead of debating what might be, since none of us has the exact same eyes, try buying a couple of LEDs and a dimmer, and see for yourself how amber, white, and red compare in terms of function, and interfering with your night vision.
 
#21 ·
I quit using red light areas long ago...:p
 
#23 ·
Hopefully this post will encourage people to think about their night vision a bit more. Many people sail at night with poor levels of dark adaptation and some simple steps can improve this significantly and enable us to use our most importance sense better.

For example many people note and/or plot their position once an hour. This is promoted as an essential part of good seamanship. While in some situations this is true, the cost in loss of night vision when in open ocean is often greater than anything that is gained.
If you are concerned about loosing GPS info a bearing and distance to a waypoint is easily remembered without being written down and would serve as a stating point for DR or celestial navigation.
 
#26 ·
Write down you lat/lon in the dark after looking at the gps with one eye covered maybe?

Regards,
Brad
 
#29 · (Edited)
Since I suspect it was my post on the other thread that prompted this thread, I thought I'd chime in. Based on my personal experience including 10 years in the infantry reading maps huddled under a poncho using a red light, I know that red light affects my night vision and is difficult for detailed tasks like determining a contour line or grid coordinate. I know that white light makes detailed tasks like that hella' easier, but truly clobbers my night vision. I once stepped into an uncovered fighting postion (Foxhole in the pre PC military) after "cheating" and using white light to determine the mag az to my next objective.

While really dimmed white light MIGHT be better, there are no readily available fixtures that provide that while dim red light has proven to work for me to an acceptable extent and fixtures are available that provide it. I have no doubt the Alpenglow fixture I'm installing will be too dim on the low setting for a task like plotting a course, but it will be enough to allow you to move around the saloon while not being so bright as to disturb someone trying to sleep. On the bright setting, I could probably do detailed tasks but I suspect it will adversely impact my night adaptation about as equally as dim white would. The difference being I dont have a lightswitch I can flip for "dim" white light and dimmable lights could easily be set too bright while trying to set them if I went to the effort to rig one up.

That said with my eyes as they are at this point in life, if I have to do a detailed task, I'll have to use light bright enough that I will likely loose some if not all of my night adaptation, and it won't matter that much whether its red or white. That's just the facts with my eyes, so I have to live with it.
 
#32 ·
I know this much - the white lights in my compass were a continuous source of irritation. When I painted them with red nail varnsih life in the cockpit at night improved immeasurably. I also know that after being down below and working with white light, I am still able to see a ship with lights on the horizon.

I guess when you're navigating coastally close to unlit obstructions the night vision issue is of more importance but at sea it makes little difference (to me anyway).
 
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