Question about light absorption - Depth vs lateral distance

[Mark Carrig]

So we all know that certain frequencies get absorbed by depth, Red, orange, and yellow being the first to go in that order.

However, does that still apply, say if two divers are at 50' depth, approx 30' lateral distance with excellent visibility from each other ?

Reason I'm asking is I've got a night dive coming up next weekend, and rather that attach a standard green glowstick to my cylinder, I was thinking a red, orange, pink or any other color, so our dive group could tell who's who based on the color.

What do you think ?

 

[tursiops]

Yes, red is the first color to be absorbed by water, it matters not which way you look. 50 ft is 50 ft. Go for blue.

 

[rick00001967]

what a great question. i like how you think.

 

[Mark Carrig]

what a great question. i like how you think.

I think all crooked ! <LOL>

 

[OTF]

Light is absorbed at the same rate and wavelengths whether vertical or horizontal through water - we're just used to most of the light coming from above.

A blue or green glowstick will be visible marginally brighter/farther than a red or yellow one. But probably not a big difference for your purposes. Telling similar colors apart might be difficult though.

Adding something to help identify divers is a good idea. I always appreciate when my buddies have obvious brightly colored gear or different light setups so it's easy to tell who's who. Fluorescent colored gear works well underwater.