Judgments of the Visibility of Colors Made from an Underwater Habitat

Judgments of the relative visibility of colors were made during the La Chalupa dive from the habitat located in 100 ft of Caribbean water. Judgments made with colored targets viewed against the water background were in agreement with previous studies that is, bright colors were the easiest to see and dark colors disappeared the most readily. However, when the colors were viewed against a light gray background, dark colors were the nost visible. It appears that negative contrast under water is superior to positive contrast of the same amount. In addition, small diurnal changes were found with green increasing in visibility and orange decreasing as the day wore on.