Study on the Underwater Visibility of Net Twines by the Human Eye-I

Underwater Visibility of Black Twines and Grey Plates

Abstract

The visual range of black twines and grey plates was measured succesively in a tank water, illuminated by diffused light from flourescent lamps for varying physical conditions, namely, colour and reflectance of an object, turbidity of water and brightness which might have direct effects upon underwater visibility. The visual range of black twines and grey plates decreases with the increase of attenuation coefficient, and with the decrease of diameters. However, the visual range of grey plates has different tendency from that of black twines, namely, plates of smaller reflectance become more visible than large ones with the increase of attenuation coefficient.