Lights underwater

[Brodie.davis]

No doubt a really noobish question.. but hey I am curious.

When I was at 22m looking around a reef, whenever I turned my light on the beam and spot seemed to be either red or pink. Is this normal or was I going even more insane. The beam is your traditional yellow torch beam at the surface.

I am guessing this is because the amount of natural red light down at that depth is nearly nill, and yet everything still looked normal colors (obviously my brain has adjusted for the color differences on the way down to maintain some form of normality), so when a full color spectrum beam is visiable it looks red.

 

[Ed Marshall]

I have a UK pocket dive light that I use in the lake where I dive. It has a xenon flashlight bulb that is yellow-white at the surface, but underwater it turns to a lavender-violet color. I've always assumed this was because of the dissolved and suspended matter in lakewater. I know that doesn't really answer your question; I guess I'm adding my own parallel question...

Ed

 

[Manta Aria]

Usually this is due to particulate matter in the water column I believe. The beam will seem pink or orange due to Phyto or zooplankton in the H2O. I'm not absolutely certain of this but 95% sure. If it's a yellow beam ( or white) at surface, this does does not change, instead the conditions around you do. What kind of light is it?

 

[TheYellowSubmarine]

Even at 22m, a lot of red light from above the surface has dispersed. So your torch is providing heaps more red light than is already around. If you want to test it, take something bright red down with you. You'll see that it looks dark blue as you go down. Now shine your torch on it. It'll be bright red again.
The best example of this that I've seen is of diadema's. Underwater they look black, but shine a torch on them, and they look amazing!
This is what they look like with a light on them:
http://www.seathings.co.nz/divelocations/whiteisland/whiteisland.htm

 

[1_T_Submariner]

Good Question Brodie I'll be watching the responses too.

 

[grod101]

It has to do with the light spectrum. at different depths you lose certain colors of the light spectrum. So you inducing light brings out certain colors that you couldn't see with natural light at that depth

 

[Jim Kerr]

It has to do with the light spectrum. at different depths you lose certain colors of the light spectrum. So you inducing light brings out certain colors that you couldn't see with natural light at that depth

This was taught in your OW course. Your light is bringing out the natural colors that are lost due to the ambient light at debth.