This week I’ve had a rush on finishing up my paper for next Wednesdays’ archaeology seminar at Glasgow Uni where I’ll be talking about the St Kilda blackhouse for the first time. When I get to this stage with a model I always feel like I want to do more, but for the meantime I’m happy with the scene as it conveys enough of what I want to discuss in my thesis as it stands.
With the blackhouse I wanted to construct a narrative around the 18th and 19th century written accounts of the island together with the vast early 20th century photographic archive. The model is still ongoing, but the scene is beginning to take shape. We see a woman (I like to think its Mrs Gillies from the archive photographs!) sat at the central hearth boiling a kettle, surrounded by various items essential to life on the island. A quern stone sits near the door ready to grind cereals into flour. Ropes lay waiting to be untangled and fish hang from the ceiling to smoke over the peat fire. As all these little details are added, it’s beginning to feel a lot like home. The more depth the image has the more an audience will be drawn in and will engage with the site.
On the more technical side of things some of you may remember the tricky business I had with the roof before Christmas, a problem I solved by taking James Hephers’ wise words from TAG 2011 to heart. He said “If you can’t draw something, if you can’t observe it then put pen to paper, then you don’t understand it.” Back in December I definitely fell prey to that! When I began to model the roof and consider the structure in detail something didn’t quite sit right. After careful study of the archive photos I noticed that the blackhouse roofs had at some stage been replaced with a more makeshift bitumen structure. After comparing the 1930′s photographs with much earlier photographs of the Street, I came to the conclusion that the gable ends of the blackhouses were modified to accommodate these replacement roofs. Presumably the thatch took too much upkeep on a structure which was no longer inhabited once the cottages were built in the 1860s, and as such they were modified.
So in order to understand the structure in more depth I turned to Chris MacGregor from Historic Scotland who sent me a series of books on the construction and maintenance of the Arnol blackhouses on Lewis.
Although the blackhouses on St Kilda are smaller than the ones on Lewis, the principal is the same.
I used the manual to base my model on, and modelled each element separately.
In the case of the blackhouse gable ends, I realise of course that I’m not the first person to notice the discrepancy between the remains still standing today and the photographs showing low rounded roof ends. But regardless, this example goes to show that it was my process of visualising that aspect of the structure that led me to the conclusion.
It wasn’t until I consulted the maintenance document for the blackhouses at Arnol on Lewis which had detailed diagrams of roof construction that I realised the gable ends couldn’t possibly have been peaked. I was stumped initially because I found I couldn’t model the roof with what the scans were showing me – it just didn’t make sense structurally. Naturally I didn’t understand it until I considered its construction in detail. Scanning essentially produces a 3D surface model, not a digital surrogate for the site, which is why it is vital to add interpretation to the digital record and not just to accept the data as it stands.