Today was the last day that the Ironbridge Gorge Museums would be open until March. I thought it would be a good opportunity to get up early and investigate the Tar Tunnels, a man made construction running 1000 yards into the hill at Coalport in the Ironbridge Gorge.
I’d seen a few photographs of this place and have been meaning to take a look since I moved here. The tunnel was built in 1787 as part of a coal mine, it’s about 5 ft high, widening to 6ft after the first 50 yards and lined entirely in brick. A railway track runs the length of the tunnel, but it is closed to the public after about 150 metres.
The story is that as the miners drilled into the hill, they noticed tar (bitumen) oozing from the walls. In fact you can see to the sides of the tunnel, quite large pools of liquid tar, gathering in natural caverns. The Victorians used this to waterproof boats that carried coal to Ironbridge where it fired furnaces used in constructing metalwork. Later, once the automobile had begun to make its presence felt, this stuff was used by John McAdam to provide a binding agent for his revolutionary road covering.
It is said that the people who made their living mining this area were permanently stained by constant exposure to this treacly substance. They were known locally as the “Black Imps”. I wondered how many cancers went unobserved or whether this naturally occurring substance is carcinogenic?
To the technical stuff: This place is pretty dark so I used a tripod and made a series of long exposures at f8 at various points along the tunnel, the aim was to get as much in focus as possible, front to back, along with maximum sharpness. Conscious of the likelihood of other people arriving to explore the site, I exposed for about 20 seconds adjusting the ISO between 100 and 400 to make those exposures possible. I underexposed a couple of stops less than the meter suggested, in order to minimise the effect of the lights. A little processing in Lightroom to get some more contrast and a tiny bit more saturation to emphasise the yellowness of the brickwork and invoke the atmosphere of the 1780’s.