The term “absorption” comes from physics and designates the weakening of radiation when it goes through different matters. In diving, this means the weakening and change of the colour of light under water.
The individual light particles are absorbed differently by water. Therefore light under water always becomes weaker and the colours appear to be changed.
Rules of absorption through water
Up to a depth of 9 metres, water absorbs the red components of light: That is the reason why the area directly under the surface of the water appears greenish.
Up to 30 metres, water also absorbs the yellow components of light, so that everything at this depth appears to be plunged in blue light.
As of a depth of about 90 metres, no more light gets under water, so that here “absolute darkness” prevails.
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