Archaeological Conservation in the Museum








Today at the Kelsey Museum of Archaeology, we are working on artifacts for our next special exhibition, “Pearls of Wisdom: the Arts of Islam at the University of Michigan.” It features art and artifacts from the ancient Islamic world. In the conservation lab, we’re examining the artifacts to document their physical condition as well as details of their construction and decoration.

In these photos, Kelsey conservator Caroline Roberts is examining filters from the (broken) necks of Fatimid-period jars. The decorative filter designs were carved while the clay was still a bit wet, before firing. Many of the designs show animals, like this lion (below), and would only have been visible to the person pouring liquid into or out of the vessel. We like archaeological conservation because every day we’re looking at daily life artifacts and thinking about how people lived in the ancient world. As conservators, we look at artifacts in an especially technical way, looking closely for details of manufacture, evidence of use, and subsequent deterioration.

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The conservation of Pitt Rivers archaeological models

The conservatin of Pitt Rivers archaeological models from 1890’s

Part 4

Watch our conservation video:

An Aim Pilgrim Trust Conservation Project

This year, Salisbury Museum was awarded a grant from the AIM Pilgrim Trust Conservation Scheme to conserve the models. As these four models are so heavy and fragile, the Wiltshire Conservation Service moved some of its equipment to create an conservation laboatory at the museum and opened the doors to the public.

Conservation exhibition hall

At many museums there is only ever enough space to display a small proportion of the collection at any one time. These models are very large and although they provide a significant resource, they do take up a good deal of space within a gallery. To make the most of the gallery space, smaller examples of Pitt Rivers’ models have been on display.  By conserving these large models today, the Conservation Service will ensure that they will be protected and remain in good condition for the future.

The Pitt Rivers excavation models

The four Pitt Rivers models depict excavations at Cranborne Chase

Rotherley: a Romano-British settlement excavated by Pitt Rivers in 1886-7

The model of Rotherley is made of solid wood, whereas the other three are made of plaster of Paris supported by a wire frame. The largest model, the Woodyates hypocaust measures over a metre long and takes 6 people to lift!


Wansdyke: a bank and ditch earthwork probably dating to the C5th AD, excavated in 1889•

Woodyates Hypocaust: part of a Roman settlement, 1889-90

Woodyates Hypocaust: part of a Roman settlement, 1889-90

Bokerley Dyke a bank and ditch earthwork possibly of late Roman date, excavated in 1890

Bokerley Dyke a bank and ditch earthwork possibly of late Roman date, excavated in 1890

Condition of the models

The 3-dimensional model of Bokerley Dyke, for example consists of a wooden frame filled with plaster which has been painted to show details of the site and its contours. The model is dirty and dusty, with heavy deposits over much of the surface and cobwebs evident in some areas.

Dirt and dust has built up on the objects over time and in some cases, this has changed the colour of the models and stained other areas.


The wooden structure of the models has split and cracked in many areas. Wood shrinks and expands, reacting to the levels of humidity in the atmosphere. As the wood expands, this can force it to break and split giving it an uneven, damaged surface.


Where other materials, such as paint or plaster are attached to the wood, the uneven surface puts a strain on the paint; stretching or crushing it until the paint or plaster cracks and breaks off. Some fragments of paint or plaster have fallen off and been lost.


Three of the models have been attacked by woodworm. These are insect larvae, which eat their way through the wood and form complex tunnel systems inside the structure. Woodworm thrive in damp environments. If left untreated, the infested wood can be so badly damaged that it will crumble away completely.

Why is conservation necessary?

Our conservation treatment will help to make sure that the models survive so that future generations can see them. Without conservation treatment, the models would continue to deteriorate. The woodworm infestation would weaken the wooden frames to the point where they could collapse. The chips and paint loss mean significant details are lost. The surface dirt, dust and stains make the models harder to understand and appreciate for their craftsmanship and information.

Treatment Proposal:

  • Clean the wood and painted plaster to remove dust, dirt and staining
  • Consolidate areas of flaking paint
  • Adhere the separated fragments of plaster and paint
  • Fill areas of missing plaster where necessary for structural stability
  • Treat the woodworm infestation to prevent further structural damage

Conservation treatment

All solvents, adhesives and techniques were rigorously tested in the laboratories before treatment commenced to ensure that no ill effects would occur to the models. Solubility tests were carried out on paint samples and the suitability of each adhesive in terms of bond strength, appearance and penetration were assessed.

Dry cleaning of the model surface

Stable areas of the surface were dry cleaned first with a museum vac and soft brushes to removes loose dirt and debris.

Smoke sponge cleaning

The stable surface areas were then cleaned with smoke sponge (vulcanised natural rubber) to remove more ingrained deposits of dirt and dust. Any smoke sponge debris was removed with a museum vac and soft brush.





Model – partially cleaned


Consolidation Consolidation1

Fragile flaking areas of paint were consolidated with an acrylic solution with distilled water.

Plaster and Japanese tissueAreas of exposed plaster were stabilised using a facing of Japanese tissue adhered with acrylic adhesive. Areas of unsupported plaster have been stabilised by filling underlying gaps using Japanese tissue and injecting a acrylic solution with distilled water.


Areas affected by woodworm infestation where cleaned with a museum vac and soft brush to remove any loose frass from the infestation. These areas where then sprayed with a water-based insecticide.

Why aren’t the models going on display?

Made-to-measure storage crates are being constructed for the models so that they are protected from the environment and pests which will prevent any further damage happening to them in the future. The bespoke crates will make it much easier to manoeuvre the models around the museum, without causing further damage.

For more information:

Visit our website:

Or contact us:  Tel. 01279 705500

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Itchy trowel syndrome

Jude Jones and Dr Yvonne Marshall in the finds hut

Jude Jones and Dr Yvonne Marshall in the finds hut

I went along yesterday to our Basing House excavation (currently underway in partnership with students and staff from the University of Southampton).  Officially I had my Conservator hat on, but once the duties of handing over a dry box and some silica gel were performed, and having found the finds hut running like clockwork I confess to whipping the trowel out and jumping in the nearest pit 🙂

Claire Woodhead, Conservator

For  more detailed progress reports, follow the dig on

A Day in an Archaeological Conservation Program

I’m a Conservation Specialist for the UCLA/Getty Conservation Program, a graduate conservation training program specializing in the conservation of archaeological and ethnographic materials.  In our 3 year course, we train students in the methods and techniques used for the examination and preservation of objects and have them understand the properties of materials, how they deteriorate and ways to slow down or prevent further deterioration.

In a typical day our students attend lectures in the morning on various aspects of conservation and then follow that in the afternoon with work in the lab.  We just had an intake of a new class in the Fall of 2011 and they spent their first year learning about and working on materials such as archaeological ceramics, glass, metals, and  textiles.

In one course they learned about the deterioration of archaeological ceramics and the damage caused by soluble salts. Students then determined how to identify the salts and remove them. Here a student is taking a conductivity reading of wash water as she desalinates a small ceramic vessel.


Archaeological Conservation in Northern Highland Ecuador

I spent this summer working as a conservator for the Pambamarca Archaeological Project (PAP), located in northern highland Ecuador, near the town of Cangahua.  As the conservator on the project, my job was to examine and conserve the finds excavated to ensure their long term preservation and to aid in archaeological research.  Most of the work taking place here is focusing on sites and fortresses located on various hilltops in the region.  The research hopes to understand the indigenous cultures known as the Cayambes, that lived here before the Inca conquered this area in the 1500’s, and also to look at the interactions between the groups after that conquest.

Most of my work is based in the lab and focuses on processing the finds that come in each day.  This can be something as simple as washing some sherds to something more complicated like reconstructing an entire ceramic vessel.  I also sometimes work on site helping archaeologists excavate and lift fragile artifacts.  This is my second year working on the project and here are some of the things I do during a typical work day:

Area where we work


The site of Quitoloma, one of the hilltop fortresses excavated by PAP.


Finds that come in, such as pottery sherds in bulk, need to be washed daily.


When enough of a ceramic vessel is preserved, we reconstruct it. Here I am starting to reconstruct the neck and rim of an aribalo, a vessel form used to hold liquids.


This a painted aribalo that was reconstructed. The rim and neck are missing.


Because of the missing upper section of the vessel, some of the joins are not well supported. This fragment only attaches on one side and needs extra support. Conservators sometimes do something called “gap-filling” to fill missing areas to keep certain fragments in place. The red arrow points to an area where a fill was placed (made up of a mixture of a resin known as Paraloid B-72 mixed with a material called glass microballoons to make it thicker) to fill the gap below the sherd to support it.


Sometimes conservators are called to the site to help archaeologists excavate and lift fragile material. Here I am preparing to lift a fragment of a burnt reed mat.


Here is a section of the burnt mat in situ. It was found on the floor of an Incan store room with a thick layer of burnt corn on top. Organic materials don’t often preserve well, but luckily this mat was burnt allowing it to survive this long in the soil.


The mat was very fragile and in a lot of pieces so it could not easily be excavated and lifted.  I needed to do something called block lifting where you excavate around the object and then lift it out in a block of soil. Here is the mat after a facing of Japanese tissue and a reversible resin are applied on the exposed surface. This helps to hold all the fragile fragments together during lifting.


Once lifted and back in the lab, the mat could be carefully excavated from the soil and consolidated with a dilute resin when needed to strengthen it.


Here is the mat after treatment. It can now be examined and studied to identify the materials and methods used in its construction.


Not all of our work is just treating artifacts. Conservators spend a lot of time documenting and recording the treatments they undertake on artifacts. Here a student helps to enter data about artifacts excavated into the project database.


We also spent time labeling the artifacts in the lab. We used a barrier coat of Paraloid B-72 applied to a discrete area of the artifact to write the catalog number on using an archival ink pen. This would allow the artifact to be linked to its catalog number, and the archaeological information in the database, in case it ever got disassociated from the label in the bag it was packed in.


Since the excavation is run as a field school, it means that students are on the project as part of a course to learn about archaeolgy and archaeological field methods. This gives me an opportunity to teach students about conservation and have them help me in the lab if they are interested. Here a student helps me find joins for a vessel I was reconstructing.


So as you can see, archaeological conservators are kept really busy on excavations doing a wide range of activities.  If you are interested in learning more about conservation and what conservators do, or think you might be interested in pursuing studies in conservation, you can check out the website for the American Institute for Conservation or the International Institute for Conservation for more information.



Can you tell what is it yet?

A day in the life of an archaeological conservator – part 2

Its been slow, hard work but have managed to reveal more of the iron object.

Not quite halfway

Woo hoo looks like we might have an early Roman miltary sheild boss.  Want to crawl off home as now really tired, plan to sleep on the tube, but not bad for a days work on the air abrasive.

Archaeology Conservation at HCC Museums Service

We are lucky at Hampshire Arts and Museums Service to have a group of trained and professionally accredited conservators, looking after our collections in store and in our museums across Hampshire.  We are spread over the different disciplines – my responsibility is mainly archaeology.  Although I initially trained as a historic objects conservator at the University of Lincoln, I have a background in amateur archaeology which was what spurred me to go into conservation.  I wanted to know what happened to the objects once they left the site!  My working days are varied, and can include bench conservation work, stores work (repackaging etc.), environmental monitoring, mount making, outreach, training and exhibitions work.  Some of that will be happening during the course of today!

Archaeological Conservation at the Kelsey Museum

At the University of Michigan’s Kelsey Museum of Archaeology, my colleague Claudia and I provide conservation for the Museum’s daily activities as well as for two of its excavations. Today we’re working on objects from Karanis, a Graeco-Roman farming town in Egypt, where the University of Michigan excavated in the 1920’s.

These objects will be shown in an upcoming exhibition here at the Kelsey Museum, Karanis Revealed, and they are currently undergoing conservation.

Two of these objects, the knife and the inkwell (top), will need conservation treatment before they’re exhibited. The knife blade, made of iron, has active corrosion that could get worse during the exhibition. The inkwell, made of faience, has cracks and areas where the surface needs to stabilized. The painted bone on the lower right just needs extra TLC; low light to protect the paint from fading, and special handling since the paint is powdery and comes off easily when the bone is touched.

The research and examination undertaken by conservators can help archaeologists understand the materials they excavate, but the primary goal of archaeological conservation is to preserve excavated artifacts. It would be sad if something that’s survived for 2,000 years fell apart after excavation for lack of care!