Colours are dependent on light, the primary source of which is sunlight. It is difficult to know what light really is, but we can observe its effects. An object appears coloured because of the way it interacts with light. A thin line of light is called a ray; a beam is made up of many rays of light. Light is a form of energy that travels in waves. Light travels silently over long distances at a speed of 190,000 mi (300,000 km) a second. It takes about eight minutes for light to travel from the sun to the earth. This great speed explains why light from shorter distances seems to reach us immediately. The spectrum of white light consists of six basic colours arranged in a specific order: red, orange, yellow, green, blue and violet. Although Newton understood that a beam of light of a particular colour is always deviated by the same amount, he did not appear to understand why this is so. So, your shiny new ‘Pink Pop Up’ is not what you perceive it to be when its underwater. The deeper the water, the less effective the colour is.

Light penetration (sunlight) for which each color effectively disappears is surprisingly shallow. Colour loss underwater is due to the phenomenon known as; ‘Selective Absorption’. Visible ‘white’ light is composed of the following spectrum of colours: • Violet • Blue • Green • Yellow • Orange • Red (Given in the order of increasing wavelength). Underwater there is a rapid (exponential) loss of light intensity which depends upon the wavelength of each component. This phenomenon is due to vibrations and deformations of water molecules excited by the absorption of light. The absorption is strongest at longer wavelengths, the exact values depending upon the water's transparency (sediment, pollen, weed growth, aquatic detritus, water quality / minor pollutants, etc). Red, the most affected colour, is reduced to 1/3 of its intensity after just 1 Meter. Yes just 1 Meter underwater and it AINT RED any more. It is essentially lost after a distance of 4 meters underwater. ( Yes folks. Red disappears and is gone, at 4 metres. That’s 16 foot-ish, and it’s totally gone, it is in fact changing colour constantly depending upon the depth. So when the industry is selling you its new Gucci Coloured Pop Up, be careful. Very careful indeed. Tight Lines. TT.