flash light for diving what colour

what colour light would be best for diving in when the water is not crystal clear , or does it depend on the reflect substance that is in the water making it cloudy , i wanted to make a led light for a friend but wanted to know what could would be best , any info would help

Ant

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ant:
what colour light would be best for diving in when the water is not crystal clear , or does it depend on the reflect substance that is in the water making it cloudy , i wanted to make a led light for a friend but wanted to know what could would be best , any info would help<HR></BLOCKQUOTE>

Well, the Navy uses an argon laser for undersea illumination. The blue-green beam penetrates the normally somewhat turbid seawater farther than any other color.

Since you probably don't have a 20-watt argon ion lying around, I would suggest using a combination of white LEDs and blue-green LEDs. Personally, I might try some setup where you could switch between the white & the blue green plus run them simultaneouslly... or just make two lights, one blue-green and one white.

$0.02

With a dive light it is best to have a really tight beam if you are in murky water. Water will spread out the light and shine back in your face. So tighter is bettter. This is why true dive lights are not real useful out of the water, to tight of a spot.

Brock

so i would want a blue-green light with a narrow beam to work best under water when the water is murky , so the nicha blue-green 20,000 mcd leds would be a good choice ?


Ant

Well.... In murky water even 10 20,800 led's isn't going to do much. You really need a bright incessant, maybe a Pelican Stealth.

Brock

It's not an LED, but the PlasmaBeam is an ultra Thin beam light used by Deep-Sea Drivers working on oil rigs. Portable Daylight I think was a term used...

I expect the Pelican Magnum with what could be the world's thinnest beam would work very well underwater... Maybe replacing the bulb with an LED(s) - keeping the Reflector?

Hi Ant!

I made a divelight about 3 years ago and my experience was: You cant have enough power!

I dont think you can build a divelight with LEDs as you have a much too wide beam and WAY too little power. I made some experiments and came to a light using standard 50mm Halogen lamps with reflector. They can be obtainded in different beam angles. The narrowest was 10 degrees. They also are made with power ratings from 20W to 75W. You could also use a 35mm lamp (they rate up to 50W).

My suggestion for a diving lamp:

- One 50W halogen lamp
- A strong NiCad accupack, preferrable from Sanyo (2000 or 2400 mAh in SubC case) consisting of 10 cells. This should give you 20+ minutes runtime. If you need more runtime, add a second pack, which can be switched on seperately. (The weight of one SubC cell, both capacities, is 56 gramms).
- A watertight housing made from a aluminium tube with O-ring tightened plexiglass as lens (attached with many screws).
- A reed-contact switch, switching a MOSFET, that can handle the power (The magnetic switching is by far the most watertight construction).

Hope I could help,

Just buy your friend a Pelican Stealth light. 4AAs, bright as snot, really tight beam. It's made for diving, and has several other certifications, as well.

Hi Ant, I've got a little experience with dive lights (been mfg them for 12 yrs.). Murky water is not a suitable environment for LEDs as a primary light source (great back up, though). LED's are too wide, even with the 25% narrowing paralax through a flat port. Clear water they're great. Your friend probably has a light they like, if they're an active diver. A nice LED backup would be 10 white 20 deg. & 4 BL-GN. Use a light with a flat lens to tighten up the beam underwater.

Thanks for all the info about dive lights; it looks as if the power and a thin beam is best.

I was only asking about colour because I had read some where that fish who live in cloudy water see in the infrared light range , I know we can't see that , but just thought that maybe a led light of the right colour would work more efficiently than a white light led .

but i looks if a Halogen lamp is by far the best sort of light

Ant

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Size15s:
........the PlasmaBeam is an ultra Thin beam light used by Deep-Sea Divers working on oil rigs. Portable Daylight .......<HR></BLOCKQUOTE>

Sorry, just caught on to that - the PlasmaBeam is actually waterproof too !?!?
The mind *boggles*

lite-lover