Any outdoor event in Scotland is half about anticipating what the weather might do. Deep Time, the opening event of the Edinburgh International Festival, is no exception.

Expectations are high for the one-off projected performance on Edinburgh Castle. Winds have been gusting all day, and heavy rain in the early evening is more than enough to question if the event would go ahead.

But Edinburgh is no stranger to changeable weather and just as the gates open to admit a few earnest folk and photographers keen to secure a spot, the sun finally makes an appearance. By 10pm the streets under the western side of Edinburgh Castle are full and a hush comes over the crowd as a large ticking antique clock appears high on the Castle wall above. Thirty minutes remain before the event that will pay tribute to the ideas of one of the largest characters in the Scottish Enlightenment, James Hutton, the father of modern geology.

Through his theory, called Deep Time, Hutton proved the earth was constantly being formed through the changing layers of erosion and sediment. Edinburgh is a fitting place to stage Deep Time, being a cityscape of volcanic rock and distinct land formations that have amazed visitors for centuries. Using Edinburgh Castle as a canvas to showcase to the world both the historical work of one of Edinburgh’s own and the advancement of current technology is a magical combination, the perfect launch for Edinburgh International Festival.

It’s not the first time Edinburgh Castle has been used as a giant movie screen, as during the Royal Edinburgh Military Tattoo the opposite side is often used as a backdrop. Deep Time is on another scale altogether, the culmination of 42 projectors, 15km of cables, a highly talented team at 59 Productions and the epic music of Scottish band Mogwai coming together for this free twenty minute performance that thousands are now waiting for.

As the ticking clock melts away and the entirety of the western side of Edinburgh Castle lights up, the story of Deep Time commences. We are slowly carried back through the history of different constructions of Edinburgh Castle, before Castle Rock crumbled away to darkness and we begin again with the very heartbeat of time itself.

Volcanic eruptions, crashing tectonic plates, the beginning of organic life, dinosaurs, and fossilisation are all projected onto Edinburgh Castle in a whirlwind of colour. The soundtrack by Mogwai blends seamlessly into the visuals, creating a truly immersing experience.

Deep Time carries us through to the present day and hundreds of photos of people who have connections to Scotland are broadcast before an image soaring over Edinburgh appeared and we fly towards the Castle from above. We watch in fascination as the image of the Castle merges with reality and we are back in the present day. A huge beam of light shoots into the night sky and the simple words “Welcome, World” herald the opening of the Edinburgh International Festival. Chatter commences among the crowd once again and any worries about the weather are forgotten as the audience try to take in what they have seen.

A high quality video of Deep Time, the one off opening event of the Edinburgh International Festival, can be viewed on their website and Facebook page, and certainly sets the scene for what’s to come between now and 29 August.