Visualising lithic use wear traces – photo stacking

It is not always immediately apparent to non-specialists what we – use wear analysts – do and see and how we can be certain of our observations. This is partially due to the imagery many use wear analysts produce. In a recent paper A. van Gijn (2013) reflects on the current state of the field of lithic microwear or use-wear analysis and points out a number of aspects of our work in which improvements are possible or even necessary. These, in my opinion rightly, include an increase in sample sizes (e.g. by scanning tools with a stereomicroscope before moving on to higher magnifications); more incorporation of ethnographic data; a standardisation of practise and nomenclature; embedding the use wear traces in the cultural biographies of artefacts and providing better quality imagery.

The basal end of a Mesolithic scraper from Arconciel/La Souche, Switzerland (quartzit au grain fin/Ölquarzit). Left a normal photo. Right a composite photo of the same part of the artefact. Taken with a Keyence Digital Microscope.

The last point can be achieved by photo-stacking through the use of specialist software or microscopes, such as the digital microscope I use, which are able to make composite photos. The image above shows what photo stacking or composite photos allows you to do.

One major drawback of the microwear approach is the lack of convincing visual evidence. The pictures generally shown at meetings are fuzzy and lack depth of field. Usually only a small part of the photograph is sharp, namely the spot of polish we want to address. Although insiders may usually see and recognize what is being discussed, it is little wonder that the general audience has no idea what it has to look at and remains rather skeptical. There is much to gain from improving the visualization of the microwear traces. – A. L. van Gijn (2013 – p. 3)

Typically, it is difficult to make microscopic photos of larger parts of artefacts that are in focus. Photo stacking, however, allows exactly this: an increased depth of field with much larger parts of the artefact shown in focus. This way not only the traces, but also their contexts can be visualised. I find this technique does not work very well in all situations or for all raw-materials or for all traces. Nonetheless, it makes our work more effective and it will surely allow us to communicate our methodology and findings much better not only to fellow specialists, but also to non-use wear specialist archaeologists and the general public.

Gijn, van A. (2013). Science and interpretation in microwear studies, Journal of Archaeological Science, DOI: 10.1016/j.jas.2013.10.024

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Traversar III – a photographic record

Autumn has arrived in the Alps. The grass is losing its green lustre, leaves are slowly turning brown, farmers have moved their life-stock from alpine summer pastures down into the valleys and snow is expected later this week. Time to have a first cautious look back on this summer’s archaeological activities in the Swiss Alps.

I already wrote once about a small project we, a select team of expert alpine archaeologists (of course), started with the aim to study the archaeological remains at a number of the most important passes in the Grisons. This summer we were mostly active in the San Bernardinopass region. We also surveyed some areas in the Upper Engadin Valley which are to be subject to development in the near future. (For this we were officially commissioned by the Archaeological Unit of the Canton of Graubünden.)

We were lucky with the weather and were able to do all we set out to. We had some interesting results and although dating is difficult at this stage, we expect our finds to be both of medieval/early modern as well as prehistoric dates. While we are cleaning up the documentation, analysing the results and waiting for the C14 dates, I thought I posts some photos giving an impression of the fieldwork.

And if you are interested in the archaeology of the Alps, why not have a look at the alpine archaeology blog? Students of the Alpine Archaeology: tools and techniques e-learning course at the Universität Zürich will be blogging here this semester (DE).

During the fieldwork we discussed archaeology and bandes dessinée. We talked about the book Le soleil des morts, by comic artist A. Houot and archaeologists A. Gallay. (I believe it is not in print anymore.) I would be very interested in hearing about other good examples (in any language), so do get in touch!

Remains of one of the many old incarnations of the road leading from the north over the San Bernardinopass.

Documenting a – probably early modern age – animal pen.

Test trenching under an abri.

Near the pass there are number of quarries for building material for the pass road. Presumably this building once housed road or quarry workers.

One of our many constant companions in the field.

View from the San Bernardinopass to the Valserhorn, near which we also surveyed.

Two archaeologists and the remains of a probable shepherd’s shelter.

Often, modern finds like these from an abri-sous-bloc in the Upper Engadin, are indications that there might be remains of older occupations as well. Sadly not this time.

Archaeology and sardine tins: lunch breaks through the ages

“A deserted camp with empty sardine tins gave proof of Newcombe and Hornby.”

T. E. Lawrence – Seven pillars of wisdom, 1935, p.250

In the Swiss Alps for many hunting is an integral part of life. When doing archaeological survey work and excavating in the Alps one often comes across little sites dating to the 19th and 20th century: the remains of hunters’ camps, sheltering from the elements, most often under abris, or rock shelters. These sites mostly consist of varying combinations of beer bottle shards, bottle lids, a cartridge or two and drinks cans and – particularly Swiss – small metal pots which contained paté. Sometimes we even find the remains of a fire. The sardine tin, however, is almost always part of these assemblages.

The presence of such assemblages often coincides with us archaeologists finding older traces of humans using rock shelters while hunting or shepherding. These can date back to any period from the Mesolithic to the early modern era.

The photo below I took in 2012 in Lisbon, Portugal. Sardine tins: the universal sign of past human lunch breaks.

Sardine tins on a building site in Lisboa, 2012.

Photograhpy – First adventures with an Agfa Synchro Box

My first camera was red with a big separate flash, 35mm of course. As an archaeologist I have used a large array of cameras over the years. They range from normal analogue 35mm SLRs and very early digital cameras (I hardly dare to think about the quality of those photographs!) to high-end DSLR’s. On the site I’m working now we even use a  120mm film Hasselblad!

Most archaeologists seem to have some affinity with photography. And I guess that is true of me as well. It was thus fun to find this AGFA Synchro Box (produced from 1951-1957) in a box in my parent’s house. It must be the very camera with which those little childhood photographs of my Father and his family were made.

So, we cleaned it and we tried a film. It is truly amazing how simple these boxes are! The camera takes a bit of getting used to, though. It is quite tricky to use the viewfinder and determine what will actually be on the photo. Photos 1 & 2 are the results of that first film. The rest come from the second attempt.

Not very happy with the processing of Photos 1 & 2: Ilford Delta 400 Pro, b & w processing, the format of the prints is wrong (lost some at the short sides) and colour printing. Photos 3, 4 & 5 are better (Ilford FP4 plus, b & w processing and printing) even though they are just contact prints. (I then scanned all of them to be able to post them here.)

Church, Unterseen, Switzerland, Mai 2012. Afga Synchro Box, Ilford Delta 400 Pro

Excavation Unterseen/Untere Gasse. Mai 2012. Agfa Synchro Box, Ilford Delta 400 Pro

Laatsch, Switzerland, Mai 2012. Agfa Synchro Box, Ilford FP4 plus

Carolingian Church in Mistail, Switzerland, Mai 2012. Agfa Synchro Box, Ilford FP4 plus

Carolingian Church in Mistail, Switzerland, Mai 2012. Agfa Synchro Box, Ilford FP4 plus

There is a colour film in the Synchro Box now and I am curious to see the results of that.

Recumbent Stone Circles, Castles and a Shell Midden – archaeological photography

I came across these photos. They are contributions to Picturing The Past – Capturing Aberdeenshire’s Archaeology, a photography competition focussing on archaeological sites and monuments in Aberdeenshire.
They brought back good memories of fieldwork in Aberdeenshire, Scotland, digging and surveying Recumbent Stone Circles such as those on some of the photos. I also love the photo of the Mesolithic Shell Midden Sands of Forvie, Newburgh by Erin Taylor Sharp (Children’s category)!