:: Color Correction with Adobe Photoshop - Part 1

Problems with Underwater Photography

Underwater photography has been around long enough for all of the problems to be recognised and most of the solutions discovered. The result is that for every problem there is an equal and opposite solution even if a compromise is sometimes needed.

LOSS OF LIGHT

Water acts as a very efficient mirror and a sponge. Any light rays which hit the surface of the water at greater than 45 degrees are reflected back into the air.

The light which does penetrate is then absorbed far quicker than on land because water is much denser. The result is that light levels drop drastically the deeper.you go.

In addition to its density, water holds matter in suspension which scatters light around and hinders its path into the deeper water. This ability to suspend matter causes "visibility" problems. The poorer the visibility, the harder it is to obtain quality results.

The solution is to try and dive when the water is clear and calm as choppy seas reflect the light back much more. In addition, if you dive at midday, the light will be at its brightest and if you keep in shallow water there should be plenty of light.

LOSS OF COLOUR

The next problem is that water affects colour. The clearest purest water has a strong cyan or bluey/green cast and absorbs different colours at different rates. As a general rule, the result is that red is absorbed at approximately 15 feet, oranges at 30 feet, yellows at 60 feet and greens at 80 feet. This only leaves blue and black which doesn't leave much scope for colour photography.

The solution is to stay shallow where none of the colours are affected or if you wish to go deeper, take your own light with you to restore the colours. This is done by using flashguns or continuous lights. The colour cast can be reduced by using filters ? red to reduce the blueness associated with tropical water and magenta to reduce the greeny British waters.

LOSS OF CONTRAST

The next problem is that the visibility underwater reduces your horizons. 100 foot vis on land causes major aggravation but would be ideal for the underwater photographer. Not only does it limit your horizons it also reduces the contrast and this in turn affects the clarity of your shots. With black and white film the blacks are grey and the whites aren't clean whilst with colour film the colours are muted.

The solution is to keep the water between you and your subject to a minimum so that the contrast is as high as possible. Adding extra light will also increase the contrast but may cause further problems by lighting up suspended matter. Fortunately, modern films are much more contrasty than before.