Lighting Carlsbad Caverns

May 10, 2011

CarlsbadLights (2)

Photographer: Tommy Hornbeck
Summary Author: Tommy Hornbeck

May 2011 Earth Science Picture of the Day Viewer's Choice

The current lighting in Carlsbad Caverns is being replaced in favor of the new LEDs (Light Emitting Diodes). This is being done not so much as a cost-saving measure but rather because by using LEDs the exact light frequency or color emitted can be very carefully selected. Algae growing in the cave have been a problem since lights were first introduced. Algae blooms near and around the lights were not only unnatural and unsightly, but damaging to the cave as well. By adjusting the exact frequency of the light emitted to that which algae are insensitive, the algae can be stopped or greatly reduced. The park service has already converted one underground room as a test site and the results are very encouraging. The cave is now illuminated by a combination of incandescent, mercury vapor, and fluorescent lighting, each of which gives off very different colors. Up until now, as the light bulbs have been replaced, the whole feeling of the cave changed as the colors changed. The new LEDs will give a more accurate feeling for the natural color of the cave without the dramatic effects produced by the older lights.

The lower photo was taken in 2008; the upper one in 2011. In the upper photo, there's a bright light at bottom center, missing in the lower photo, but the lower photo shows a spotlight on the right center stalagmite, missing in the upper photo. Note that the overall illumination on the ceiling has changed from blue to yellow over the past three years.
  
Photo details: Camera Maker: NIKON CORPORATION; Camera Model: NIKON D80; Focal Length: 20.0mm (35mm equivalent: 30mm); Aperture: f/8; Exposure Time: 30 seconds; ISO equiv: 100; Exposure Bias: none; Metering Mode: Matrix; Exposure: program (Auto); White Balance: Auto; Light Source: Unknown; Flash Fired: No; Orientation: Normal; Color Space: sRGB. The colors in the two photos have not been altered or retouched in any way, although long exposures with digital cameras will intensify saturation somewhat.