Four divers are seen here cruising at about 40 feet along a typical reef in the Philippines, near the Capone Islands. The visibility was exceptionally good, at over 80 feet.
This photo appears to have a bluish cast, but without artificial (strobe) light, the reef, though naturally colorful, appears blue-green at this depth. The longer wavelengths of light are filtered by the water column above, beginning with red, then orange, yellow, green, blue, indigo, and violet, in that order (acronym ROY G. BIV).
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