Archaeology, Photography and HDR

Minard Castle. Photo (cc) Mike 138.

If it were true that the camera never lies, then photography wouldn’t be a problem. It does though. Or at least a photograph isn’t a wholly objective record of reality. A couple of years back I was happy with this and was discussing illustrating an event using a photo mosaic. The universal reaction to this idea was horror, which surprised me. What I was planning to do was take a photograph of a site and manipulate the sky behind it – and make clear that this was a reconstruction not an original image. The overwhelming negative reaction meant that I’ve never done this. The alternative, that I draw a reconstruction of the event, and throw in a few imaginary people, with speculative hairstyles and clothes, standing around in small groups – without any evidence for this – was considered fine. I assume that people are ok with drawings being highly speculative, but still expect photo-quality images to be ‘real’, whatever that might be.

Photo editing is a serious problem as programs like Photoshop make it easier than ever to mess around with the exposure or the colours of a photo. If you’re photographing the result of an experiment, where the amount of colouration is an important part of the result, like in biology, then changing those colours is effectively falsifying your result.

I am wondering how far this extends to archaeology.

Thanks to About Archaeology I found this bibliography about archaeological photography on the Wayback Machine. It’s useful if you’re interested in techniques, but I can’t see anything about ethics on it. In contrast you can read about ethical problems manipulating photos on photography sites. There’s also discussion about manipulating photos for astrophotography and microbiology. In contrast there’s nothing in academic archaeology. I don’t know if that’s a genuine lack of thought, or if that’s just me not reading much on the topic. I think there may be a problem, because if photography is an issue then it’s not just an issue for archaeological photographers, but for any archaeologist or historian wanting to interpret a photo. For some archaeologists it appears that photos just happen.

It’s not the case if you work in an archaeological unit. I’ve got an Archaeological Site Manual from MoLAS. It’s got a whole section on photography, including elements of what you should and shouldn’t do. So you clean up sections and dampen them to make colours more visible. What you don’t do is scratch lines in a section to highlight one stratum from another. Unfortunately it doesn’t discuss the photographic process much. It assumes that the important photography will be done by a MoLAS photographer, which not everyone will have around.

There certainly are books on specialist archaeological photography, but I don’t know of any which seriously tackle digital photography. Please point me in the direction of any useful articles in the comments if you can. Digital photography does pose new problems and HDR is a good example.

One of the many mistakes I make with photos is that I don’t get the lighting right. I aim at what I’m interested in and the exposure messes up. The focus is exposed correctly, but the shadows are too dark to see anything in and the light parts are washed flat. HDR is High Dynamic Range photography and it tackles this problem. In a perfect world the camera takes three photos at the same time. One is a normal photo. One is over exposed which reveals detail in the shadows. The last is underexposed, so you can see see detail in the lighter areas of the photo. A HDR print mixes these together so that the lighting works across the photo. You’re not putting anything new into the photo, or anything that wasn’t already there. Can you use these photos in academic archaeology?

Sound II. Photo (cc) Rob Ball.

Done well, they could be useful. Quite a few sites are not well lit, so being able to take a photo which could bring out details in shadowed walls, and still preserve patterns on walls lit by sunlight in the same room could be very useful. I like the photo above of a cloister in Winchester Cathedral by Rob Ball. It’s a HDR photo and it’s really rich in detail. There’s the tiling in the floor, the brick work which looks sharp in the distance, and the bricks on the lit side of the wall are distinguishable despite being a lot lighter. In a publication it would be a very compact and efficient use of space. At the same time is something lost when you remove light and shadow?

Antelope Canyon in standard exposure (cc) Mark Freeman and HDR (cc) Farol Tomson

If you want to capture details of the walls as well as the shaft of light then I’d say Farol Tomson’s photo is the better one. However, Mark Freeman captures a striking difference between light and shade. If you were working on a publication about Antelope Canyon which one would you use? I’d guess the one which best shows whatever it is you want to to talk about. At this point you’re almost cherry-picking your data to best fit your argument. Whichever photo you use will be constructed to show something to its best advantage. To photographers this is old news, but given archaeologists and historians agonise about the bias in other people’s writing, it seems odd to skip biases in photography.

Jodrell Bank Telescopes Mk2 and Mk1a.
0.005 sec exposure at f/3.8637
ISO 800 – see more.

It’s not been a problem in the past, but advancing and easier to use software could start including these kind of features as auto-enhance options. Galen Rowell, who seems to be very keen on real photography sees no ethical problem witj HDR (scroll down to Dec 2000 entry – h/t Random Alex) If it helps clarify something, then that may be no bad thing, but at the same time it may also be sensible to start talking photography more serious by noting basic details. EXIF files, standard on many camera now, automatically log many details. Hence the information about this photo stored on Flickr.

I clearly need to read more about photography, not just in archaeology but also art history and the sciences. Recommendations are welcome below.