got a light?

[scubafire]

I am curious....I know that at various depths, your eye loses the ability to discern certain colors beginning with red. If you are diving at those depths, should you bring a light so you can see those colors or does that not help? I also hear that using a tinted mask helps....but I have never seen anyone use one. Any ideas?

 

[fppf]

Its not your eyes, its the water. Water acts like a filter, first to go is red. At 60 feet red will look black. Bringing a light will bring back the true colors.

 

[fisheyeview]

I am curious....I know that at various depths, your eye loses the ability to discern certain colors beginning with red. If you are diving at those depths, should you bring a light so you can see those colors or does that not help? I also hear that using a tinted mask helps....but I have never seen anyone use one. Any ideas?

If you want to see the colors (other than blue) then a light will do the trick. The reason you lose the colors at depth is because the water is filtering out (refracting) the light. The deeper you go, the more light that is filterd out. If you add an artificial light source, you add the light back in that has been filtered out.

A tinted mask will add some reds back in, but this is only because you are looking through a red lens. I tried one once, and it bugged the cr*p out of me, but YMMV.

 

[diver 85]

I am curious....I know that at various depths, your eye loses the ability to discern certain colors beginning with red. If you are diving at those depths, should you bring a light so you can see those colors or does that not help? I also hear that using a tinted mask helps....but I have never seen anyone use one. Any ideas?

You are correct, the longer wavelengths 'go' 1st ie reds @ about 760 nm. then down the line orange, yellow, green , blue. indigo, & last violet @ about 360 nm......Knowing that, I never carry a lite unless we're known to be going into alot of caverns etc........that's what a camera is for, take your shots with a flash & enjoy the colors on the surface.......

 

[jefffalcone]

If you want to see the colors (other than blue) then a light will do the trick. The reason you lose the colors at depth is because the water is filtering out (refracting) the light. The deeper you go, the more light that is filterd out. If you add an artificial light source, you add the light back in that has been filtered out.

A tinted mask will add some reds back in, but this is only because you are looking through a red lens. I tried one once, and it bugged the cr*p out of me, but YMMV.

Not to be picky, but this isn't actually refraction. Refraction is when light bends from passing through different mediums, like in a prism. Refraction is what causes objects to be magnified underwater when viewed through a mask, but the lose of color is caused by absorbtion.

 

[fisheyeview]

Not to be picky, but this isn't actually refraction. Refraction is when light bends from passing through different mediums, like in a prism. Refraction is what causes objects to be magnified underwater when viewed through a mask, but the lose of color is caused by absorbtion.

It sounded good until it was discovered to be incorrect.

 

[diver 85]

It sounded good until it was discovered to be incorrect.

But,........he's pretty close..........

 

[Temple of Doom]

Also worth noting that a tinted lens is not going to be 'adding' reds back in, merely it reduces the amount of blues, while leaving the reds unchanged, making it appear like there are more reds. Unless it's really bright out, you're going to be getting less light into your eye with a tinted lens.

Though, if it is really bright out, then an amber/reddish lens can actually increase the reddish and overall amount of light entering your eye. It does this by filtering the high-intensity blueish light that your pupils react to limit. With less blueish light entering your eye, your pupils are able to dilate a little wider, and allow more reddish light in.

Craig

 

[GA Under Water]

Even when it’s very clear, water absorbs light passing through it, transforming it into heat. However, water doesn’t do this uniformly because wavelengths with less energy absorb more easily. Therefore, it absorbs colors toward the red end of the visible spectrum more rapidly than at the blue end. This is why red tends to disappear very quickly as you descend. Usually you don’t see much red below 4 metres/15 feet because little light of that wavelength reaches any deeper. This doesn’t mean that the color red suddenly blinks out at 4 metres/15 feet, but that practically speaking, red is gone. Color absorption is a continual process, so there’s less of all colors at 2 metres/6 feet than at 1 metre/3 feet. This gradual filtering process affects the weaker wavelengths faster.
In order following red, water more readily absorbs orange, yellow and green. The loss of color is why underwater photographers use flash even in very bright conditions. The light from the flash doesn’t travel through much water, so it restores the absorbed wavelengths for a colorful picture. This is necessary for good quality underwater photos, even with modern digital cameras that can partially correct for color absorption

sorry forgot quotes.

 

[Temple of Doom]

Here's an interesting graph that illustrates the absorptive characteristics of water for different wavelengths (from this page):



You can see water's absorbency is quite low for visible light (hooray for divers!), though it does have a fairly steep increase as you go through the spectrum from violet to red.

How the absorption coefficient affects the light absorbed is described by the Beer-Lambert Law.