3D scanning and the future of clay tablets

By Nicky van de Beek

In June, Annelies Van de Ven (Melbourne University) joined us for a week to 3D scan a number of cuneiform clay tablets from the Böhl collection at the Netherlands Institute for the Near East. At the end of the week she gave a workshop to present the first results. We interviewed her during her work.

What is it you are doing?
I am digitally mapping a small part of the Böhl collection using photogrammetry and RTI [Reflectance Transformation Imaging].

What is the difference between those techniques?
Using photogrammetry, you essentially create a 3D model based on photos. You move the camera around an object, shooting it from all sides, and the software calculates the position of the camera. With RTI you rather move the light source while keeping still both the object and camera. The software calculates how the light is reflected, which gives you a very clear 2D image that allows you to see the texture of an object in detail.

At the moment, RTI cannot yet be converted to 3D, so it’s useful to apply both techniques. A 3D model of the tablet, to study the material context and spatial rendering of the text, and the RTI image that is more easily readable.

What other techniques can be used?
An often used technique is blue light scanning, for example with the handheld Artec scanner that combines photography with a laser. But these machines are expensive and can break down in the field. It’s easier and cheaper to bring a camera, white sheets and some lamps to your excavation. Custom officials of some countries are also not too fond of strange electronic devices such as blue light scanners.

Why is it important to 3D scan clay tablets?
The clay tablets in the Böhl collection have been baked. Many clay tablets in the field however are unfired, very brittle and disintegrating in front of your eyes. You want to map them as efficiently as possible, without moving them. Sketching takes a long time, and you can miss details. At the site of Ur in Iraq the tablets are brought to the museum at the end of each field season, so what do you do when you find 20 tablets on the last day? With photogrammetry and RTI you could capture everything and send the digital files to experts all over the world for interpretation. Your options are much less limited that way.

Also, it can be difficult to get access to archives and tablets in museums. Imagine if you are living in Iraq, and would like to visit the NINO, but cannot get a visa. In the near future, much more material will be digitised. I think we should strive to put everything online and provide access to everyone. Sometimes that is not possible. Museums say: If we tell everyone what’s in our archives, we will be a target for looting. But on the other hand there is the importance of sharing. People will also gain more understanding of why clay tablets are important if they can see them and learn from them.

In a museum exhibition, a visitor may see a tiny piece of baked clay. It is hard to imagine how such an object was made, used and stored, and why it is important to us now. Online we can present the tablets with much more context, really paint the bigger picture. That way you can more easily attract the interest of the public.

This tablet (LB 2043) is a Late-Babylonian legal document from Sippar. The enigmatic text records the transfer of *something* from the house of one man to that of another. On the reverse is a list of three witnesses.

What can we learn from clay tablets?
At Ur, we were excavating a house. Was it the dwelling of an ordinary person? An elite official? We know little about houses from this period. Most of the material culture was taken away, the site had been abandoned by its inhabitants. In the house we found a bunch of tablets with two names: the owner of the house, who was a general, and the name of a priest. Mostly they dealt in silver and goats. The priest worked in a temple a few hundred meters away. Suddenly we had a much better idea of how the city was laid out and how things were connected. It was a eureka moment: we knew who lived there, whom he was in contact with, what he did. That is something architecture fails to tell you.

What would you love to do in the future?
Teach digital methods to archaeologists in the Middle East. It is interesting for them to learn this extra skill, that they can apply in excavations and museums. They can teach it to others in turn. No need to import expensive scanners, just use a camera, tripod, and the material you have readily available. We have difficulty financing excavations, and for them it is the same.

How can we learn these skills ourselves?
Try it yourself to get the hang of the basics, do a lot of searching and testing. Watch a lot of tutorial videos, read a lot of forums. Much trial and error.

Learn more about photogrammetry:
Photogrammetry using Agisoft Photoscan
Cuneiform tablet photogrammetry workflow

Learn more about RTI:
CHI (Cultural Heritage Imaging) has developed the RTI method, and they have an excellent forum. There is also a very good course by Kathryn Piquette at UCL, but there are costs involved.

The resulting 3D models will be made available online and used within the Persia and Babylonia outreach project Archives in Context.

Architecture, Archaeology, and Iraqi Palaces – An Interview with Dr. David Kertai

By Uzume Wijnsma

Dr. David Kertai is an expert on the Assyrian Empire and the architecture of Mesopotamia (present-day Iraq). He is currently affiliated with the Martin Buber Society in Jerusalem, and he is conducting research on the architecture of ancient Babylonian palaces. David recently visited Leiden for a conference on Nineveh at the National Museum of Antiquities. Persia and Babylonia met with him there to discuss his work, the (im)possibility of excavating in Iraq, and how he ended up in the discipline of Near Eastern Archaeology in the first place.

First things first: you once started as an Architecture student at the TU Delft (the Netherlands), but you eventually switched to ancient history and to the architecture of ancient buildings. How did that come about?

During my studies at Delft I realised that I wasn’t that interested in personally creating a building – something an architect probably should be interested in. I, however, was more drawn to the theory and history of architecture. So I decided I wanted to study architectural history. But in the Netherlands that’s only possible as part of (Art) History, and I didn’t feel like doing another general study. In the discipline of Ancient History, however, it was possible to specialise immediately: you had to choose between Roman, Greek or Assyrian.

So you just sort of stumbled into it?

Yes. Ancient History was the most specialised study I could find.

Why did you choose Assyrian over Greek or Roman?

I think Greek and Roman architecture is relatively boring. So many people have already worked on that. The Middle East, however, seemed interesting to me.

So what’s the difference between ancient architecture and archaeology?

I think the difference is that I’m not much concerned with archaeological details when I look at architecture. Those details are always very problematic with old excavations (editor: many sites in Iraq were excavated in the 19th and early 20th centuries, with methods and tools far below modern archeological standards). In the case of the ancient palace at Babylon, for example, they’re now looking at all of those details anew. That will surely result in all kinds of small chronological changes: perhaps a few doors or walls of the palace should be re-dated to Phase A rather than B, and perhaps certain renovations were conducted at an earlier rather than later time. But I’m ignoring those details at the moment. I look at the palace as if that were the palace.

What are you looking at exactly? How big the palace was, in what style it was built, which colours were used on the walls..?

No, not quite. I’ve always been interested in how people shape their lives through architecture, in this case at the Babylonian court. The idea is that the way in which you shape the space around you influences the way in which people interact with each other. For example, the big difference between the palace of Babylon and the palaces of Assyria is that movement in the latter is extremely concentrated: everyone has to walk through a handful of hallways to get from A to B. You can’t simply walk from one room to the other. You always have to go outside and use the same hallways and open courts to reach another part. So if you close off one hallway, you’ve practically closed off an entire section of the palace. In the Babylonian palace, however, everything is connected with everything. Almost all of the rooms lead to yet another room and there’s almost no room with a dead-end. There are infinite ways to get from one part to another. That’s actually quite comparable to European baroque palaces. We might think that a bedroom is an isolated room, but in ancient Babylonia and European baroque the bedroom is just one of the many rooms you can walk through to get to some other place. In other words: there are no isolated areas.

Why do you think they chose for that style of architecture?

I’m not sure. What you can see in baroque palaces is that the way the architecture was used partly depended on someone’s rank. For example, there were small spaces within the walls themselves: they (rather than the regular rooms and hallways) could be used by servants. But they could also be used by the most important people, such as the king: kings had the right not to be seen when they didn’t want to be. But everyone else had to use the regular rooms and hallways. I don’t think Babylon had this sort of hierarchy. There are no hidden doors or hallways in Babylon, nor are there obvious servants’ quarters. So: I don’t know yet!

You’ve said that you see yourself more as an archaeologist than an Assyriologist; so what kind of excavations have you been to?

I’ve been to about five or six excavations. I started with a Dutch excavation team in Tell Sabi Abyad. That site was essentially of Neolithic date, so about 8000-7000 years old. Lying on top of the site were the remains of a small Assyrian farm of Middle Assyrian date (ca. 1200 BC). I’ve also done an excavation at Tell Kazel at the Syrian coast, near Lebanon (ca. 1200 BC), and in Tell Halaf where I excavated the Late Assyrian period (ca. 900-600 BC). But in the last two years I’ve mainly been to Iraqi Kurdistan as part of the Iraq Emergency Heritage Management Training Scheme of the British Museum.

That’s quite a time-range, from the Neolithic to the Middle Assyrian period! Is that all equally interesting to you?

Well, I think the Assyrian period is the most interesting historical period, but sites of Neolithic date are actually much more interesting to excavate. Because they are so much more unpredictable. For example, Assyrian walls are made of standard clay-bricks and are mostly built at a right angle. So you can pretty much predict where you can find the next standard brick; there’s not much variation. Neolithic walls, on the other hand, go into all kinds of directions. It’s harder to excavate, but also more exciting.

Are you primarily excavating temples and palaces, or also smaller houses, farms and shops?

That depends. Neolithic sites are often villages, or storage facilities. But Assyrian buildings are almost always monumental. That’s partly because it’s difficult to find smaller buildings. One reason for that is continuous occupation: the lower-town of Tell Halaf, for example, is still inhabited today and can therefore not be excavated. The only part of the site where we can excavate is the citadel, which largely consists of monumental buildings. But another reason is: we don’t really know how middle or lower class people lived in antiquity. Maybe they didn’t even live in houses. Maybe they lived in huts. And those are much more difficult to find and excavate.

You often hear that 19th century archaeologists focused on monumental buildings (temples, palaces) at the expense of domestic architecture. That can result in quite a lopsided view of Assyrian life. What is your take on that?

Well, first of all, the archeological techniques of the 19th century were not yet good enough to find non-monumental architecture. So even if they’d wanted to, they couldn’t have. It’s only at the end of the 19th century that they’re able to recognise mudbricks. And when the Germans excavated Assur, the old Assyrian capital, they also actually found all kinds of houses. So the interest was always there. As for more recent times: the political situation in Iraq has made excavations difficult. At Nineveh, for example, almost nothing has happened for the last 100 years. I mean, I know some people went there in the late 1980s, but almost all work ceased after the First Gulf War. And some people excavated at Assur in about 2000, but that stopped after 9/11. So we’ve had little chance to rectify and add to the excavations of the 19th century. We essentially know little about Iraq. And that’s also why we know much more about Syria, a country which early archaeologists paid much less attention to. Until recently, of course.

The political situation in Iraq and Syria is of course tragically well-known. But some parts of the region seem to have become more stable. Are any archeologists working there at the moment?

Most people are now excavating in Iraqi Kurdistan; but there are also a few people in south Iraq. Not a lot, but a few. But, yes, it remains a tragic fact that the original core of our discipline – Iraq – is also the place where the least amount of work has been conducted in the past generation. Most of the people who have excavated there are now around retirement age. So there’s a huge gap.

And there’s probably still a lot to dig up…

Yes, but not only that: when excavation projects reappear, students will reappear as well. More people will be engaged with it, and old things will be put on the table again and discussed and debated. Now, our knowledge is often based on what archaeologists were thinking 50 or 100 years ago. There has been some reinterpretation, but still… Archaeology is primarily based on where archaeologists are excavating. Most of the students will work on that material. And as there have been almost no excavations in Iraq in the past couple of decades, it has also suffered from a lack of interest generally.

What about archaeologists from Iraq itself?

There have always been Iraqi archaeologists and students. Even in the 19th century: the person who excavated the most was Rassam, a local Iraqi from Mosul – even though he wasn’t always considered a ‘worthy’ colleague in England, simply because of his nationality. Nonetheless, he has actually done a lot of the work. But it has been tough the last couple of years. Iraqi archaeologists and student have done enormously life-threatening work to protect the excavations, to keep a close eye on what was happening there… It hasn’t been easy.

To what extent has the political situation in Syria and Iraq influenced you own work?

Well, all excavations in Syria have stopped. And extensive damage has been done to some of the archaeological sites and museums. Some colleagues, such as Olivier Nieuwenhuijse (Leiden University), are putting in a lot of effort to chart the inflicted damage, and to save what can be saved. But it’s hard. Most people in Syria and Iraq have better and more important things to worry about, of course… But, yes, I think it is the duty of archaeologists to concern ourselves with the tiny part of our own expertise, and to focus on the small area where we can make a difference.

Thank you for your time, David. I just have one last (happy) question for you: is there anything in your work (e.g. any site that you’ve been to) that was especially interesting or beautiful?

If I had to choose, that would be Tell Sabi Abyad, a village of Neolithic date. The structures there were especially well preserved, from 1 to 8 meters high. So you could really stand in the old streets and houses. And that felt pretty special after 8000 years…