Bristol is a city built on the rise and fall of the tides. Historically, the tides would make their presence felt, right in the heart of the city, lifting boats up to the quaysides at high water and stranding them in the mud below at low tide.

From the beginning of the 19th century, however, with the creation of the Floating Harbour, the water level was kept constant and that connection was lost.

‘Tidelight’ symbolically re-established that dynamic connection between the city and the sea.

The interior of Bristol’s glass-fronted M Shed museum was filled with light that changed colour in direct response to the rise and fall of the tides. At night the whole building became a giant ‘lantern’ on the waterfront, responding to the sea beyond.

To make Tidelight happen, continuous, real-time water level data from tide gauges out in the Bristol Channel was sent back to a computer inside the building. 

A piece of software converted this data, on-the-fly, in to a form that directly controlled the colour value of RGB lighting, already installed throughout the building as well as additional temporary lighting in the glass fronted foyer.

Very low water was translated in to red light. As the water rose on the turn of the tide, the sensor data gradually caused the hue to transition through shades of orange, yellow, green and blue, all the way to violet at very high tide.

The full tidal range out in the Bristol Channel corresponded to the full colour spectrum.

And as the tidal ranges varied over time, so more or less of the spectrum was reproduced accordingly. During a neap tide, the tidal range is low. The high tides are less high and the lows less low.

On these occasions the coloured lights in M Shed only ranged between orange and green. On very high spring tides, though, the building was lit in a particularly intense violet, and during particularly low spring tides, the ‘lantern’ it glowed a deep, blood red.

Bristol’s connection to the sea has always been a big part of its identity. And the coming and going of the tides has been inextricably woven in to its story.

From John Cabot and his crew waiting for the tide to lift the Matthew off the mud to allow passage along the Avon Gorge – and out beyond the Bristol Channel in to the blue toward that infinite horizon.

To the tides that determined the passage of ships in and out of Bristol during the most shameful chapter of its history – the Transatlantic Slave Trade.

To the network of connections, across the globe, of legitimate trade, that brought such a rich diversity of people, objects, ideas and innovations to the city.

All these things, brought in on the rise and fall of the tide are woven in to the fabric of the contemporary city. In the place names, in the buildings, in the quaysides, in the diverse communities, in the music, in the food, in historic works of art and works of contemporary street art.

This project aimed to be a small part of this ongoing story of Bristol’s connection to the sea, as an inland maritime city, and prompted conversations about its history, its geography and our vulnerability to rising sea levels in the face of climate change.

Tidelight used low energy LED lights which consumed less than 5% of the energy produced by solar panels on the roof of MShed over the same period. See the Tidelight website FAQ page for details.