Underwater lighting experts Keldan lights have produced two short animated videos that show how filters can be used to improve the quality of both ambient and video lighting. They also serve as an excellent primer on underwater lighting and the issues associated with it.
Keldan’s Ambient Light filters attach to Keldan’s 4X and 8X lights and correct their output to match the spectrum of light that actually occurs underwater:
Their Spectrum filters attach to the camera or lens and correct the spectrum by filtering out the blue/green end of the spectrum. They are designed to be used without lights/strobes or to be used in conjunction with lights equipped with the Ambient Light filters above. The Ambient filters correct the spectral distribution of light underwater to allow white balance to be achieved in a natural looking way.