Wednesday, January 18, 2012

Thierry Hennet documents the colorful salt formations of Danakil Depression in Ethiopia's Rift Valley

Swiss biologist and nature photographer Thierry Hennet picked a very special place to visit in Africa recently. "The Danakil depression in North East Ethiopia is much like California's Death Valley, just deadlier. Both places are shaped by the earth's tectonic plates drifting apart. They feature salt flats and sand dunes, their lowest points are below sea level and they are extremely hot. Because of the torrid temperatures, Danakil is best visited in winter when heat seldom exceeds the 40°C (100°F) mark. Like Death Valley, the Danakil depression hosts impressive scenes that make it a favorite destination for photographers.

"Whereas Death Valley has no permanent residents, Danakil is the home of the Afar people, who live by rudimentary herding and by trading salt cut into rectangular slabs from the salt flats by Lake Assale. The salt then travels into the Ethiopian highlands by an almost continuous procession of camel caravans. The photo above captures the choreography of this salt trading industry as precisely orchestrated beginning with the arrival of the camel caravans to the small village of Ahmedela every evening.

"At dawn, the caravans leave Ahmedala and proceed to the salt flats. The view of the endless lines of camels on the salt flats is truly mesmerizing. In this image, my 3-stop soft-step ND Grad helped darken the sky while maintaining a bright line just over the horizon, thereby providing a strong contrast with the dark silhouettes of the caravan. I kept changing between my soft-step and hard-step Graduated ND filters while on the salt flats. With the rising sun low on the horizon, these amazing filters enabled me to achieve a wide range of effects.

"On the salt extraction sites the caravans meet the local workers, the salt breakers called 'Focolo' and the salt cutters, the 'Hadalimera,' who prepare square salt plates of exactly 7 kg (15.4 pounds). These men deserve great respect as they work using rudimentary tools under the burning sun and without eye protection against the blinding light. After loading their camels with salt plates, the caravan leaders head back to the highlands to deliver their precious load.

"After this day of photography, I was quite impressed by how well the Singh-Ray Graduated ND filters helped retain the vivid colors throughout my images, as clearly seen by the radiant sunburst. However, at this point of the journey I had not yet discovered a very different application for my 3-stop hard-step ND Grad during my visit to the next landmark of Danakil.

"The drift of the tectonic plates have turned the Danakil depression into one of the most active volcanic areas on earth. The local volcano Erta Ale even features one of the few worldwide active lava lakes in its crater. The view of this lava lake at night is absolutely breathtaking, but the extreme lighting conditions make it quite a challenge to properly expose. To capture both the incandescent lava in the foreground and the night sky, I rotated my 3-stop hard-step ND Grad by 180-degrees -- upside down -- to reduce the light intensity of the lava lake as shown on the image above. The 30-second exposure at f5.6 provided a way to highlight both the incandescent walls of the crater and the burning smoke against the dark blue sky. Unfortunately, the overhanging and unstable rim of the crater made any effort to capture of the whole lava lake risky. I certainly did not want to repeat Gollum’s fall.

"Whereas Erta Ale offers an exclusive spectacle, there's another volcano in Danakil that shines with a unique natural phenomenon. The volcano Dallol is located close to the border with Eritrea, meaning that the area is only accessible under military escort. To make Dallol even more intimidating, the site was awarded the world record of the highest average annual temperature by reaching 34°C (94°F). In spite of all this apparent hostility, the unearthly view of Dallol made my visit so exciting I immediately forgot the extreme heat and the reigning strong smell of sulfur gases. The surreal colors and the fantastic shapes found in the crater of Dallol gave the impression I was on another planet. The hot springs constantly transport minerals and salt to the surface, yielding saturated yellow and orange structures surrounding green ponds of sulfuric acid.

"To emphasize the saturated colors and to minimize the light reflection on the acid pools, I used the Singh-Ray LB Neutral Polarizer throughout my stay on Dallol. The following image shows how the Polarizer revealed the sulfur veins in the acid pools, thus giving an almost organic impression to the scene. The image was taken with a 16-35mm ZA zoom lens set to its 16mm focal length with an exposure of 1/125 at f/8.

"The next image was taken at Dallol using the same LB Neutral Polarizer again to underline the color saturation and the gradation of green tones found in the acid pools. This image was taken at noon under bright sunlight. The Polarizer managed to reduce the glare and reflections of the bright sunlight while maintaining the sharpness of all the details.

"Based on current predictions, the Danakil depression will be flooded by the Red Sea in a few millions years. This is definitively a good reason to pay a visit to Ethiopia before these unique landmarks become the floor of a new sea. If you do make the trip, remember to take your Singh-Ray filters!"

You can see more remarkable images from Thierry's Ethopia adventure here, along with many more images from his other travels. You can also keep up with him via his website.