It is situated 300 metres above sea level, in the Rock of Gibraltar, and has caught the imagination of visitors to the area since Roman times. The Cave was often reputed to be bottomless, or part of a link to Africa, 15 miles away. With a lighting and sound system in need of updating, the Government of Gibraltar issued a very broad invitation to tender, seeking ideas for the refurbishment of the lighting and sound systems - with a short 'day' show for visitors walking through the caves and an 'evening' show for special occasions. Since the Tourist Board of Gibraltar, which manages the caves and the project, wanted a single supplier and a 'turnkey' solution, audio-visual company Electrosonic was called upon to put together a team of specialists.
Electrosonic's involvement neatly completed a cycle started nearly 40 years earlier, since one of the first projects of the newly-founded Electrosonic was a son et lumière show at the cave. Over the years, the system was upgraded piecemeal, but in 2002 the Government of Gibraltar decided on a complete refurbishment. Because of the unique nature of the project, Electrosonic assembled a team of experts which included Paul Bason of Pure Media as the show's creative director, David Atkinson as lighting designer, Richard Northwood of Coms to work on the sound system, and Lauren Lloyd to handle all the electrical and installation work.
The challenge for all was working to an open brief, while being able to visualize the final result for Government approval. Working in a space with dampness, high humidity and salt corrosion was also providing its fair share of headaches.
Lighting designer David Atkinson's brief laid down that his designs should enhance the beauty of the space, whilst also tying in with the script and specially composed orchestral score for the son et lumière elements. The12-minute son et lumière presentation in the main auditorium, delivered with all the general lighting off, plays a key role in helping tell the story of the caves. The fixtures (all the lighting was supplied by A.C. Lighting Ltd), consisted of Martin MAC and Exterior units and a host of generic lighting (Par 16s, Par 64s and AR111s), as well as halogen floods fitted with toughened glass filters. The latter are controlled by Helvar Ambience dimmers with DMX input. Other special effects come courtesy of six high-powered fans, a Cirro Lite haze machine and Diverstronics strobes.
"Working in this magnificent space gave me lots of opportunity to utilize Exterior 600 and 200 sources positioned at strategic points around the cave," explained Atkinson. "These produce deep, dramatic hues of colour, ranging from ultra-violet to deep saturated reds. MAC 500E and 250+ fixtures are used to produce an array of beam effects such as projection, water ripples, fire and dappled light, and simulated laser effects.
High-powered xenon flash tubes set below and inside crevasses simulate lightning and gunfire, while atomized water haze, used at set points to accentuate the shafts of light, simulate laser effects, creating a surface for projection." Both the MAC 500E and MAC 250+ units are fitted with custom gobos produced by Projected Image.As mentioned, the cave presented its own problems, the main one being the dripping stalactites. "During the summer months, the humidity gets extremely high, which is probably worse than actual droplets of water as it can impregnate the equipment," explains Atkinson. "Hence I chose to do trials at an early stage in the caves with various sources, before opting for the Martin Exteriors.
Projection was also a concern, as the fixtures (Martin MAC 500E and 250+) would need to pan and tilt. Therefore, they are slotted inside Tempest 'Tornado' protective domes fitted with a fan and heater to keep a constant pre-set te
