Photography in archaeology

[Jack]

Nah, differential melting of snow in a field is usually to do with earthworks, dips and shadows

Though I imagine a water-soaked pit fill would heat up slower and hold heat better than a dry subsoil.......but then you'd see that difference with your eyes.

Unless your getting blind from old age :face-stir:

But I suppose any tool that is of some use is useful..............though eyes are cheaper

[John Wells]

You can convert a normal camera so that it works at high shutter speeds in the near IR.
We shoot at very slow shutter speeds in the UV and thermal and get around this by shooting video and selecting the few good frames.
We have used a similar approach with poles. The camera is stationary for an instant when it is at the maximum amplitude of a swing.

[John Wells]

To use UV light on an open air site would you need to block out natural UV light?

You are photographing using the ambient UV light. See [URL="http://armadale.org.uk/phototech04.htm"]http://armadale.org.uk/phototech04.htm
[/URL]

[John Wells]

Nah, differential melting of snow in a field is usually to do with earthworks, dips and shadows

Here are example of images produced with both snow cover and melt:
http://www.armadale.org.uk/gormyre.htm

[John Wells]

Are the thermal/hydrological properties of natural and fill different enough to be detectable on anything other than an aerial/satalite image?

Under investigation: http://www.armadale.org.uk/dart.htm
With all the photographic techniques you are looking for any variations, including moisture content, reflectivity, emissivity and thermal inertia etc. In practice, it does not matter initially what the process is, all you want is variation.

[P Prentice]

Nah, differential melting of snow in a field is usually to do with earthworks, dips and shadows

Here are example of images produced with both snow cover and melt:
http://www.armadale.org.uk/gormyre.htm

Brilliant, bloody brilliant

[John Wells]

Maybe its something for the future when resolution improves and experiments have ironed out issues.

Resolution is not a problem in photography, even when working with a 320x240 pixel thermal imager on a kite:

(That's me at the centre!)
It is better than the usual 1 pixel equivalent per square metre of geophysical surveys.

An image which inspired me was this aerial one taken with a pencam......Yes! a 352 x 288 pixel pencam:
http://www.armadale.org.uk/cairnpapple050.htm

[John Wells]

If anyone strays into West Lothian our kite aerial photography boards are now up:
http://www.armadale.org.uk/historyheritageday.htm
along with some photos of Etna Brickworks before, during and after demolition

Or you can dig into:
http://www.armadale.org.uk/archaeologyindex.htm

[Dinosaur]

Nah, differential melting of snow in a field is usually to do with earthworks, dips and shadows

err, as I think I've already pointed out, try actually READING my original post and maybe you'll realise how stupid that post is in this context, I specifically exempted earthworks ! !

- on stripped archaeology snow seems to last longer on better draining stuff like gravel for some reason, maybe the snow on those bits isn't having warmth circulated to it from the meltwater it's sitting in? If you think of snow melting on a hard surface it's often melting from underneath with an overhang around the edges, which is perhaps part of a similar process?

@John - good earthwork/snow pics, but I'd been thinking more of semi-melted. Years back after a light snow shower the flattened part of the Rudston A cursus showed up beautifully as two white stripes (over the ditches, drainage again?) running across an otherwise melted landscape - only lasted for 10 mins and of course I didn't have a camera with me, but bl**dy brilliant!

[kevin wooldridge]

I have just received a copy of a MA dissertation from a Norwegian colleague Erik Kjellman entitled 'A photogrammetic revolution in archaeology' and detailing the use of PhotoScan as an archaeological recording medium. The dissertation is mighty impressive and I think I am now almost 100% certain that the technique works. Not quite sure how it can be applied to archaeology with even the simplest form of stratigraphic detail, but as a tool for mapping the vast open steppes of northern Norway it seems to have some advantages over traditional topographic survey (Though I would say that there is still an element of georeferencing requiring an external source).

Do you know John whether anyone is researching how to tie the images into the stratigraphic complexity of an archaeological site?

Erik's dissertation is available online at http://munin.uit.no/handle/10037/4306