Breakaway Destination Guides (International)

Neon colours do not loose their colour like spectrum colours do. Suit with neon red and "hot pink" will still send out their bright colours. When a neon colour is struck by the invisible ultraviolet it glows or fluoresces. Carry a flashlight when scuba diving, small light will reveal colours that are startling.

A large part of vision underwater is being able to distinguish different colours. Seeing colours underwater depends on the amount of light reaching the particular depth at which one is at. Another factor in seeing underwater is the condition of the waters and, more specifically, the conditions of the surface. There are several ways to make the colours easier to see. However, it is most important, to simply understand that colours change underwater and it is sometimes hard to distinguish between them.

One factor in seeing underwater is the fact that as light passes through the water it is absorbed, and much of it is lost in the process. This causes objects to lose their colour as they go deeper down or further away. To add to this, the wavelengths that make up our perception of colour are absorbed differently. The length the wavelength changes how fast the colour is absorbed. Red has the longest wavelength, after red comes orange, then yellow and so on, all the way down to the blues and purples which are the shortest.

Depending on the length of the colour's wavelengths you can predict how a colour will change underwater. For example, in clear water, the longest wavelength is lost first. So if you were in a pool swimming downward, the first colour that would be hard to see is red. Another factor in seeing colour underwater, is the condition of the water. However, something such as plankton can significantly change perception of colour underwater. This is because plankton absorbs violets and blues. So the presence of plankton would cause blue and violet objects to lose their colours much faster compared to red and yellow objects.

Understanding how colours change at different depths and in different conditions is the first step, understanding what they change to and how to work with that is the next. In clear water, if you go down far enough a red object either appears unlighted or black. The further down you go different coloured objects start to look the same colour. This colour tends to be the colour that is best perceived in that water conditions. For instance, if it was clear water, at a certain depth all the objects would start to look grey. So even before you reach a depth deep enough to make colours look black you can get easily confused between different colours. One way to distinguish between the differences is that of their relative brightness or darkness. Several of the most visible colours are light, bright colours that cause a good brightness contrast with the dark water background. If there was a different background, such as white sand, darker colours would be easier to see. Another good way to distinguish different colours is to use two colours that cannot be mixed up in any type of water. A good example would be orange and green.

If a diver is bleeding at 60', where there is no red light, the diver bleeds a greenish-black blood. Taking a photograph at 30' would result in most objects appearing green, blue, violet, and/or black. Taking the same photograph with a flash would reveal startling colours that were not seen by the diver. Carry a flashlight with you when you are scuba diving. Even a small light will reveal colours that are startling and would have gone unnoticed! Remember, the selective filtering by water occurs in any direction. So a camera's flash will also loose most of its true colour effectiveness after a distance of as little as five feet!

In open water there are several pollutants that decrease water's visibility and also change the colour and colour penetration. If the water has silt and/or clay in it, the visibility may drop to almost zero and will have a brownish colour. If water has an excessive growth of algae the colour of the water will be green. The more the algae, the darker the green and the less the visibility. Sometimes the growth is seasonal. Some bodies of water have great visibility in the winter, especially under ice where the affect of the wind stops and the bottom sediment is not stirred up. In the summer the extra sunlight and waste from summer visitors promotes algae blooms. There are other pollutants that colour the water. Tannic acid, especially from pine trees, can colour the water brown even though it may remain clear. Rotting vegetation and iron may cause a brown colour, and paper mill runoff can leave it looking similar to milk.

Beyond the red light there is a part of the spectrum that humans cannot see but can feel. It is infrared. It is also known as heat. Infrared cannot penetrate 1mm! So you might wonder how the oceans get warm if heat cannot get down into the water? It's not the heat from the sun that makes the oceans warm. It is all the colours that are selectively filtered by the water. They are "captured" by the molecules of water and are converted to heat energy because the molecules are made to move faster.

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