EQUIPMENT TIP: BLACK LIGHT DIVING

Underwater photographers looking to add a new twist to the shots from night dives might want to look at them in a new light — and we mean that literally. The light we’re talking about is fluorescence — ultraviolet light sources trained underwater, creating whole new color patterns and displays. Some of this is visible to the naked eye. Water absorbs the colors from white light with increasing depth, with reds and oranges being absorbed first. At depths below 60', orange shouldn’t be visible. If you see an orange coral at this depth, what you’re seeing is the coral absorbing ultraviolet light, giving it an orange appearance. A photograph destroys the illusion, and the coral appears dull brown.

This effect can be enhanced with ultraviolet light. Shrimp take on an eerie blue glow, and hydroids, nudibranchs, and bristleworms luminesce with strange colors. Corals tend to be especially vivid under ultraviolet light, and critters that are good at camouflage can be exposed with fluorescence.

If the notion sounds intriguing, marine biologist Charles Mazel has developed a small u/v light source for divers, the NightSea UltraBlue dive light, which retails for about $140. Check out some of his strangely colored underwater photos at www.nightsea.com. For more information, call toll-free 877-436-9262 or e-mail NightSea at nightsea@nightsea.com.