What colour will my swimming pool be?

Probably the most common question asked by clients when it comes to choosing their pool lining material is “what colour will the water be?” In the recent past this was a relatively easy question to answer, until recently the vast majority of materials suitable for the purpose were shades of blue. That is no longer the case, advancements in production technology and a shift in the demand from clients means that there are now a large number of alternatives available to suit all tastes.

A glass of water appears to us as transparent and colourless, so why when we see it in a swimming pool or indeed in a lake or the sea does the water appear to us to have a colour? Water’s blue colour is due to an effect known as the “Rayleigh scattering effect” named after a British Nobel prize winning physicist working at the turn of the 20th century. The basic principals of his conclusions are as follows.

• We all know that “white light” is in fact a mixture of seven wavelengths of visible light from Violet at one end of the spectrum to Red at the other.
• A body of water absorbs the long wavelength colours in light (Red, Orange, Yellow) much more easily than the short wavelength colours.
• The same body of water reflects the short wavelengths (blue & Violet) which is why the water appears to us as blue.
• This effect increases with the volume of water, which is why the glass of water appears clear and the shallow end of a pool will always appear lighter than the deep end.

Of course natural light will change depending on time of day and our location on the planet the perceived colour of the pool water will not be exactly the same at noon in the Caribbean as its is on a cloudy November day in the UK. The basic principal of the “Rayleigh scattering effect” remains incontrovertible though wherever we are.

So, in principle we are always starting with a shade of blue when we fill a pool with a volume of water. The question then is how can we alter the perceived colour by choosing our pool lining material. We will endeavour to explore this further with particular products from the range but the following principles represent a good starting point.

• White pool linings will produce a pale blue/turquoise pool water.
• Grey pool linings will darken this blue/turquoise colour.
• Dark grey to black linings will produce a dramatic dark inky blue pool water colour.
• Blue materials with intensify the natural blue colour, the darker the blue the more pronounced the effect.
• Pale green pool linings will shift the perceived colour to turquoise, darker greens will provide dramatic dark green pool water.
• Stone colours and anything towards the yellow end of the spectrum will shift the perceived colour to turquoise greens. The darker the colour the more pronounced the effect.

Following are some examples to help explain this:

Here a near white tile (Iconic white) produces a turquoise water colour. Note how the colour intensifies as the water deepens.

A grey tile (Serena Grigio) produces a deeper tone of turquoise.

Tresor Java a near black tile produces this inky blue water colour.

Here shaded iron blue produces a rich blue water colour.

Tresor Bali provides this rich green pool water colour.

Mallorca mosaic was used in this pool to produce this turquoise green pool water
effect.