Photography in archaeology

[Dinosaur]

Photographing a site with UV or IR? Can't see why this would be of use on a site.....As for thermal imaging cameras, yes my dad used to use them in the firebrigade, don't know how they would be useful on an archaeological site, unless you are hunting for bunnies or hamsters.

Oh dear, and I thought you considered yourself something of a scientist... :face-crying:

Think we may need to run some basic science courses for the POs...

Years back I can remember an item on Country File where they were showing how 'real-time' IR satellite imagery was used by farmers to plan crop-spraying and the like - spent the entire piece fixated by all the archaeology that the IR was showing up - anyone have any idea where such imagery can be obtained?

[Dinosaur]

@BAJR - at least the section isn't half-obscured by a yellow bucket.... :face-crying:

[Jack]

Oh dear, and I thought you considered yourself something of a scientist... :face-crying:

Think we may need to run some basic science courses for the POs...

Years back I can remember an item on Country File where they were showing how 'real-time' IR satellite imagery was used by farmers to plan crop-spraying and the like - spent the entire piece fixated by all the archaeology that the IR was showing up - anyone have any idea where such imagery can be obtained?

Wasn't talking about satellite imagery.....think I mentioned that in my post? but again I ask thermal imaging camera?

[kevin wooldridge]

There were a few fundamentals that used to apply to analogue cameras that I think 'digitally minded' archaeologists have forgotten, basically focus, aperture and bracketing. Digital cameras are a fantastic (and cheap) tool, but I despair at the use of 'Automatic' settings and single shots of objectives.....

[Dinosaur]

Wasn't talking about satellite imagery.....think I mentioned that in my post? but again I ask thermal imaging camera?

Think you'll find the question was 'has anyone tried one?', not a recommendation - but then, have you tried one? Did it work? On the basis that light snow cover often shows archaeology even in a flat field with differential melting rates (earthworks are a different matter)), one might think that there's sometimes enough thermal contrast for it to work?

[John Wells]

Very interesting! It is difficult to know where to begin.
I must say that I envy the experience that Tezet has with his aerial work.
I do not want to discuss archaeological aerial photography, which, as an amateur photographer 'working' in a new field, is my passion.
I have posted about this before: http://www.bajrfed.co.uk/showthread.php?...-the-cheap

My impression is that photography is not generally taught on courses in archaeology. This may explain why the expertise for photographing sites, landscapes and buildings is to be found in other disciplines where photography is taught. This is especially true of 3D modelling, both virtual and solid via 3D printing etc. As pointed out by ZSilvia above, creating 3D models can be quite simple with modern software, especially for aerial work. Have a play with Photoscan which can be downloaded free: http://www.agisoft.ru/products/photoscan/standard/demo/

What I find sad is that the expertise for interpreting and recording a site is with the archaeologist and yet the simple tool of photography appears to be given such a low priority.

I find modern digital cameras a right pain in their complexity. But they have a wonderful advantage over film cameras. Usually, you can simply add a filter, or filter combo, to take photos outside the visible spectrum.

For example, point your TV controller at your camera lens and press one of its button. Does the near IR LED of the controller light up on your camera screen?

In most cases the answer is 'Yes'. So add an R72 filter (~?10 on e-Bay) to your camera, to block out the visible light, and you have a near IR camera. Exposure times will be long (greater than 0.5 sec.), so you will need a tripod.
Near UV is a bit trickier and the cheapest approach is to use unmounted filters on a compact camera (~?35). See http://www.armadale.org.uk/phototech.htm. Simple lenses usually let through more near UV than others and you do have to check that your camera can see UV.

Archaeologists often look at their excavation work and say 'nothing so far'. If a palaeographer looks at an old piece of vellum, papyrus, wood or parchment which may contain writing they do not squint at it and say 'Can't see anything' and throw it away. They will illuminate it with UV to reveal the faded ink. There are a range of wavelengths that are used outside the visible spectrum for this purpose. For bread and butter archaeology this may not be appropriate but on key sites, especially if there are trace residues, having a look outside the visible spectrum may prove useful, even where the residue is diffuse, like an ink pattern on blotting paper.

Currently, thermal imaging is more expensive and you would need to fork out about ?900 for a camera (ours cost ~?2K each). Thermal imaging is not as simple as some may think but it does pick out difference in soil characteristics. However, I have a better feel (if limited understanding) of its usefulness in aerial work.

My thoughts on this topic are not new. I was initially given advice by Christopher Brooke who has worked in both the near IR and UV.

[Dinosaur]

Given recent experiences where some archaeologists can see archaeology and others frankly can't on some types of subsoil (my main bugbear around here is gravel-backfilled features cut into alluvial gravels), anything is worth a try! Shame about the long exposure times for near-IR though, probably wouldn't work with our on-the-cheap kite rig where it would be most useful and I suspect mega-polecam wobbles too much except in a flat calm.....

@Kevin - yes, auto seems to be the default setting for most diggers, but then I've spent years despairing at finding the site cameras set on 1/1000second again every time I take them out of the box...the first thing I learnt about site photography was to throw the camera manual away and experiment - after all, the guy in a white coat in Japan probably never really expected his product to be used for photographing soil down a dark hole on a sunny day.....

[kevin wooldridge]

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

[Jack]

Hmmm, not sure. Would have to see it at work.

Would need lots of experimentation.

Have seen normal aerial photography (kites and poles) create the illusion of features, but also give a better view to see actual features.

Not sure that UV or IR photography or thermal imaging would help find features in plan on the ground any better than a dowsing of water would.

But prepared to be proved wrong.

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

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

Take geophysical survey as an example......the problems are still being ironed out.

[Dinosaur]

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

What, like snow for instance?}

Do keep up....