One of the earliest known forms of writing is cuneiform, a wedge-shaped script developed by the Sumerians, around 5000 years ago. It is preserved on stone carvings and clay tablets. The survival of the clay tablets is amazing, given that most were of unbaked clay – essentially mud. Today’s Conservation Confidential (1 pm EST on Penn Museum’s Facebook page) will feature conservator Tessa de Alarcon discussing the preservation of these earliest written records.
This week’s CC will feature Julie Lawson discussing some monsters she grew fond of while working for the exhibition “Beneath the Surface” Julie will be available to answer questions via the Penn Museum Facebook page between 1 and 2 pm EDT on Friday, October 30.
Greetings from the Penn Museum’s Conservation Lab Annex (CLA)! You may remember from our first post the scale (large!) and types of objects we are going to be working on over the next few years. We are mostly working on architectural elements like doorways, windows, and columns that were part of the palace complex of the Pharaoh Merenptah, who ruled Egypt from Memphis from 1213–1203 BC. To put things in perspective, the doorway we are currently working on is over 12 ft tall and many of its fragments weigh hundreds of pounds. That means we have had to add a few new tools that are not typically found in a museum’s conservation lab. Most recently we’ve started utilizing a lot of new tools including a forklift, a gantry, and large-scale sandboxes.
As with any job, having the right tools is really important, for success and safety! We look forward to continuing to share the progress we’ve made on this project from our home offices, as we continue to work from home.
by Tessa de Alarcon
Documentation of conservation treatments undertaken in the lab is a very important part of what we in the conservation department do at the museum. One of the main reasons we document our treatments is so that conservators in the future don’t have to try to figure out what was done to an object. Instead those future conservators can read our reports and start off knowing the treatment history.
We are also sometimes those future conservators, looking back at previous treatments. This means that not only can we see an object’s treatment history, we have the opportunity to evaluate and learn from the decisions made by conservators decades ago. Some of these treatments were successful, and some were not. Now we know to avoid those treatments that clearly did not work.
I recently completed a treatment on an object that is a good example of this process. E11151 is a carved wooden figure from Nubia. It was treated before I worked on it by a conservator in the 1970’s. The photo below is how the object looked when it entered the lab at the end of last year.
In the case of this object, it was noted in the 1970’s as having a slightly powdery surface. The conservator conducting the treatment decided to apply a consolidation method that is frequently used on waterlogged wood: immersion in a solution of PEG (polyethylene glycol). PEG treatments are still done today and are very effective at consolidating and stabilizing waterlogged wood before it dries out. But because of this treatment and others done at the museum around this same time period, we have learned that consolidation with PEG is not effective on dry wood, even if it once was waterlogged. E11151 was dry wood and did not come from a waterlogged context.
The photo above is a publication photo of the object before it was treated in the 1970’s. While there is no photography with the 1970’s treatment report, there is a sketch which suggests that the object looked similar to this photo when it entered the lab at that time. As you can see there are quite a few differences in the object’s appearance as it entered the lab in 2019 and how it looked before it was treated in the 1970’s.
Two different molecular weights of PEG were used on this object, a hard high molecular weight one that was used to consolidate the powdery wood and looked white on the surface where it was very thick, and a low molecular weight one that was used to join pieces of the object together and left the surface tacky and sticky. The sticky PEG also trapped a lot of dirt and dust on the surface of the object.
The detail above shows the top of the head of the object. The report from the 1970’s states that during treatment the object began to crack and fragment. PEG is typically dissolved in water or ethanol. Both solvents were used in the PEG treatment of this object. These two solvents can be mixed together and during a normal PEG treatment the wet wood starts with PEG in water and then moves to PEG in ethanol: this helps start the drying process. As the waterlogged wood is also already wet, the PEG can penetrate fully into the swollen wood. However, in the case of dry wood, these solvents (ethanol typically has some water in it) introduce moisture into the object, and it starts to swell as wood is very responsive to moisture. It then has to dry out again after the treatment, causing the wood to shrink. This is stressful for the object. This stress is what likely caused the cracking documented in the report and visible in the image above.
Here you can see what the object looks like now that I have finished my treatment. Consolidation is a very permanent and tricky to reverse treatment, even when adhesives that remain soluble, like PEG, are used. There is currently no way to remove the PEG from this object. All I have done is reduce the PEG on the surface by cleaning it with ethanol. I also used the previous documentation to figure out where small detached fragments went so that it looks more like it did originally. While the treatment that was undertaken in the 1970’s seems to be over-treatment as it caused new problems, some more severe than the problems the object had to begin with, I do also want to recognize that it is because of past experiments like this one that I know not to use PEG on dry wood.
Because wholesale consolidation is a fairly permanent and risky treatment, I think long and hard when I choose a consolidant. I also remain aware that there is a chance that someday, some future conservator, will deem some of my treatments mistakes as well. Hopefully my mistakes will be ones that they can learn from too.
To learn more about PEG treatments for waterlogged organic materials, check out these links:
Ellen Carrlee Conservation blog: High Molecular Weight PEG for basketry
Queen Anne’s Revenge blog: Waterlogged wood – Gotta bulk it up!
Cardiff University Conservation: Newport Ship Workshop
This project was made possible in part by the Institute of Museum and Library Services.
by Anna O’Neill, Julia Commander, and Jessica Betz Abel
Hello from the Penn Museum Conservation Lab Annex (CLA)! Since Lynn’s introduction, we’ve had a little bit of time to settle into our new, off-site facility and get started on some seriously big projects. Our primary task here is working on architectural elements that were part of the palace of the Pharaoh Merenptah, who ruled Egypt from Memphis from 1213–1203 BCE. We have doorways, windows, and other objects from the palace which will be displayed in the new Ancient Egypt & Nubia Galleries to give visitors the experience of being in an ancient Egyptian building. But first, we have to put them together!
We have four doorways that will go into the galleries, all of which are very large and in many pieces. They are made of limestone and intricately carved, with traces of inlay and paint. Our first project is Doorway 1, which will be about 12 feet tall once it’s all together. It’s never been displayed before, but it was partially treated in the past. Some fragments are joined together with adhesive and metal pins, and we can tell that some of the decorated surfaces were coated with a consolidant. The fragments are also very dark and dirty from almost 100 years in storage.
Doorway 1 is in thirteen major pieces, which were all on different pallets when they were moved to CLA. With a little bit of effort and a lot of maneuvering with pallet jacks, we grouped the fragments together. It was very satisfying to figure out how all the pieces fit together and form a door!
Since we’re using Doorway 1 as our pilot project to figure out how we’ll treat the rest of the palace objects, we’ve spent a lot of time testing different conservation approaches. Since the doorway is discolored with dirt and one or more old coatings, we’ve been experimenting with gel cleaning and found two methods that work well for what we need – hot agar and Nanorestore gels® Peggy. We’ve talked about using other kinds of gel before.
Agar is a product of red seaweed and contains a polysaccharide called agarose. When it’s dissolved in water and heated, agarose forms long molecular chains – that means that when it sets, agar becomes a rigid gel that can be peeled up as a sheet without leaving problematic residues behind. The long agarose chains create pockets that hold solvents on the surface of the object, allowing them to work on grime or coatings without soaking in too deeply. You can add different cleaning solutions to agar, but plain deionized water gave us the results we wanted. We dissolved agar in deionized water and heated it in the microwave to form the solution, then poured it directly onto the surface of the stone and allowed it to cool. Applying it as a liquid means that the gel conforms well to the irregularities in the object and lets us get into all the nooks and crannies.
The Peggy 6 gel is made of poly (vinyl acetate) and comes as a thin polymer sheet. It feels a little like the gummy hands you can stick on windows – stretchy and flexible but strong. Like agar, the Peggy gel can be used with different cleaning solutions but we stuck with deionized water. The gel is laid on the surface of the stone to let the water do its work on the grime. Because the Peggy is a stretchy sheet, it can skim right over delicate carvings that might contain pigment. Another advantage of the Peggy gel is that it’s reusable – we just rinse it out in deionized water and use it again.
To clean Doorway 1 we used a combination of the agar and Peggy gels. Both gels soften the dirt and coating, and often looks pretty grimy when they’re peeled up. Once the gel is removed, the stone is wiped with cotton and more deionized water to remove even more dirt. We were pretty pleased with the difference between the cleaned and dirty surfaces, and using the gels meant that the process was much more efficient and gentler on the stone than using swabs.
Other parts of the treatment include reversing old repairs (or deciding when to leave them be), assembling fragments, and figuring out how to display the doorway in the gallery. We’ll check back in later with more monumental updates!
por Teresa Jiménez-Millas
Durante el pasado mes, he tenido el privilegio de poder trabajar en un cartonaje egipcio, y ¡no menos es la suerte que tengo de poder escribir este artículo en mi lengua materna! Me han consentido mucho en este equipo.
Poco o nada sabemos de la procedencia de la obra, fue una donación a la colección egipcia del museo por parte del Sr. Thomas A. Scott en el siglo XIX, y es un estupendo ejemplar para estudiar tanto la técnica del cartonaje como el tipo de intervenciones que se hacían en el pasado.
La nomenclatura es una derivación del francés “cartonnage”, término usado en egiptología para hacer referencia a la técnica en la que finas capas de yeso se aplicaban sobre un soporte que podía ser fibra (lino) o papiro, permitiendo la flexibilidad suficiente para moldear y obtener las formas deseadas de la silueta del difunto, algo parecido al papel maché para que os hagáis una idea. Sobre este aparejo de yeso se elaboraban la policromía y el dorado.
Esta pieza ocupaba la zona pectoral de la momia. La imagen representa una figura alada con el disco solar sobre la cabeza, posiblemente Nut, quien junto a su hermano Geb eran los padres de Isis, cuya historia es central en la resurrección de los extintos.
En cuanto al proceso de restauración de esta obra, lo primero que nos llamó la atención fue el soporte adherido al reverso, que no formaba parte del original, y por otra parte el gran número de fracturas y pérdidas que presentaba el anverso.
Por la tipología de esta obra sabemos que no era plana y que tenía cierta curvatura, pues su función era decorar y descansar en el pecho de la momia. En este caso, parece que la persona que intervino la pieza en el pasado no tuvo en cuenta esto y añadió un cartón con mucho adhesivo en el reverso, de manera que la pieza ¡quedó completamente aplanada!
En este tratamiento de conservación lo fundamental era eliminar ese soporte trasero para relajar la obra, pese a que esto supusiera que los fragmentos antes unidos quedaran sueltos y desprendidos. Este paso se hizo mecánicamente con la ayuda de un bisturí y bajo las lentes del microscopio.
Se quiso evitar cualquier contacto con un medio acuoso, pues ante una obra tan frágil cualquier fluctuación de humedad podría afectar negativamente al soporte, a las capas pictóricas y al dorado.
Con el paso de los días se pudo observar cómo cada fragmento iba recuperando su forma primigenia, recobrando cierta curvatura y relajándose. Esto determinó el resto del proceso, pues se decidió no forzar la unión de las diferentes áreas. Cada una presentaba en este momento un diferente perfil y tratar de reunirlas provocaría mucha tensión innecesaria.
Se consolidaron y protegieron todas las zonas por el reverso y se estudió la mejor manera de realizar un soporte para cada una de ellas que permitiese también su futuro montaje y exposición.
Tras muchas pruebas, preguntas y mucha paciencia de mis colegas, se decidió que lo mejor sería hacer tres soportes para las tres áreas con resina epoxídica de madera; de esta manera cada uno soportaría un fragmento, un planteamiento respetuoso para la obra que nos hace entender que el paso del tiempo y las intervenciones del pasado dejan su huella.
Tengo que agradecer a Jane Williams, jefa de conservación y restauración del “Fine Arts Museum of San Francisco” por sus consejos y su ayuda inestimable para el tratamiento de esta obra que tanto respeto me causaba.
Con mucha gratitud por haber tenido la suerte de trabajar con tan generosas personas y haber aprendido tanto en este fantástico proyecto, ¡espero algún día poder ver este cartonaje expuesto en el museo!
Este proyecto ha sido posible en parte por el Instituto de Servicios de Museos y Bibliotecas.
By Tatiana Perez
I am an undergraduate Classical and Near Eastern Archaeology student at Bryn Mawr College and this past summer, I began as a conservation intern within the Penn Museum’s Museum Practice Program. I am continuing this work through an independent study in the Museum’s Conservation Department this Fall. During my time here, I have treated a group of Egyptian faience shabtis.
Shabtis are statuettes that were made to be placed within ancient Egyptian burials for the purpose of assisting the deceased in the afterlife. The shabtis I worked on are made of Egyptian faience, a material made from silica, alkaline salts such as plant ash or natron, lime, and metallic colorants. The faience could be hand-shaped or pressed into molds, that when fired, would self-glaze. Although faience was made in many different colors, it is most often associated with a bright blue/turquoise color (using a copper colorant) as seen in many amulets, beads, and figurines.
The specific group of shabtis I worked with this summer differed in size, shape, and color. Many were previously repaired and some of these old repairs were failing. Unfortunately, these objects had become disassociated from their accession numbers and records, so there is no information on their provenance or previous conservation treatments. I was tasked with documenting their condition, and treating those that were broken or in need of re-treatment, either to remove failing old adhesives or remending those that were previously mended but now broken. As adhesives age, especially those used in the early 20th century, they can become discolored, may shrink or expand, or may become stronger. All of these conditions pose problems to the objects that can affect their future stability and ‘health’.
Since no record of the treatments existed, I used various methods to determine what worked best to remove the adhesives that were used. First, I used UV light to identify the type of adhesives. After observing that it was possibly shellac or animal glue, I spot-tested the adhesives using a variety of solvents. I found that acetone, ethanol, and deionized water worked best, so I left the shabtis in acetone vapor chambers for a few hours to allow the adhesive to dissolve.
After the old joins were taken down, one particular shabti caught my eye immediately. This lighter green-blue shabti had metal adhering one of the joins, with some adhesive underneath as well. After consulting with various conservators about this unexpected find and with help from the handheld pXRF instrument, we found that it was lead solder that was used to join these pieces. This is a very unusual (and outdated) technique for mending pottery and as head conservator Lynn Grant said, it’s likely whoever treated it last “struck when the solder was hot”. In other words, the person who last treated this object might have used the solder because it was nearby and ready to use. This conservation method was not the best way to mend the shabti and doesn’t reflect current methods we use. The body, or core, of faience objects is very porous and absorbs whatever adhesive is applied. When the solder was applied it seeped into the body of the body of the object, and made it very difficult to remove.
Though this conservation treatment doesn’t affect our understanding of the shabti, it got me thinking about how conservation ethics and practices have changed over time. As stewards of cultural heritage, conservators have the important job of fixing objects in a way that is reversible and that doesn’t compromise the object’s cultural integrity or future use. Conservators do their best to maintain the integrity of objects, for both research purposes and to preserve a piece of the culture these objects came from for future study and display. This means that conservators must also apply these ethics to objects that were treated before these standards were enforced, and take caution to prevent any further loss of information no matter how small.
With the shabti group I worked on, I used a technique that is commonly used to repair porous or low-fired ceramics. Before using an adhesive to repair the fragments, I applied a low concentration adhesive solution on the break edges to create a less porous surface and to prevent the adhesive from seeping into the body of the faience. I then used a higher concentration adhesive to put the pieces together. This specific treatment is reversible and will ideally last a century or more!
Mending artifacts can be a slow process in which a conservator attaches one piece a day. While working on this small group of shabtis for many weeks, I’ve grown very attached to them. They are all unique pieces with their own quirks, and I can’t wait to see them back together and ready for future use.
We have been notably quiet on this blog lately, but that doesn’t mean that we haven’t been making a lot of noise elsewhere!
We also have some BIG imminent deadlines, which have kept us very busy, and some of our monumental projects are so BIG that they can’t even be worked on within the Museum building. More on that soon.
All of that aside, we continue to work on projects in the Artifact Lab, that are not as big, necessarily, but are just as important. Most of the artifacts we are working on are to prepare for the future installation of our new Ancient Egypt and Nubia Galleries.
To hear more about all these projects in REAL TIME, check out our 1-hour #AskAConservator Q&A session next Monday, November 4th, on the Penn Museum’s twitter account, or visit us when the Museum is open, where EVERY day is Ask a Conservator Day!
by Adrienne Gendron
I am a graduate student at the Conservation Center at the Institute of Fine Arts at New York University, and I’m spending the majority of my summer here at the Penn Museum as part of my training to become a professional conservator. In late June, I took a break from the Artifact Lab and traveled to Villa La Pietra in Florence along with fellow classmate Andy Wolf to work on a conservation project.
Villa La Pietra houses an expansive and diverse collection that came into the ownership of New York University from the Acton family in 1994. The Actons were art collectors from England and the US who lived in Florence from the early 1900s onward. Every year, NYU students from a variety of programs travel to Florence to work on educational projects at the estate.
For the span of a week, Andy and I worked under the supervision of Pamela Hatchfield (Robert P. and Carol T. Henderson Head of Objects Conservation at the Museum of Fine Arts in Boston) to perform a complex treatment on a 17th century majolica pharmacy jar. The jar had fallen off a high bookshelf during an earthquake in 2013 and broken into 40 major pieces and innumerable tiny flakes and chips. Conservators often need to differentiate between different types of physical changes that may occur during an object’s lifetime and may choose not to intervene if an object is stable. In this case, because the damage caused by the earthquake was very recent and extensive, we decided to proceed with reconstructing the jar and minimizing the damage as much as possible.
After documenting the damage and finding the locations of each major fragment, it was time to assemble. Andy and I realized that because of the geometries of the fragments, we would have to build most of the jar in one session so the adhesive would remain tacky enough to make necessary adjustments. So, after some deep breathing exercises and words of encouragement from our supervisor, we began the assembly process.
Typically, conservators like to reassemble broken ceramics from the bottom up. That was not possible in this case because half of the jar’s foot had been completely shattered in the earthquake damage. Instead, Andy and I decided to assemble the piece upside down starting from the rim.
The assembly of the main body of the vessel took about 3.5 hours from start to finish. Andy and I worked closely together during the entire process, using pieces of black electrical tape to secure the pieces in place while they dried. We were fortunate that the outer surface was stable enough that the tape could be used safely.
After the main part of the assembly, it was time to work on the shattered foot. This was the most challenging part of the entire treatment. After many hours of searching through a sea of tiny fragments, I was able to reconstruct the profile of the missing outer edge of the foot from sixteen individual pieces.
Andy and I worked together to take a mold of the intact side of the foot to use as a guide for matching the curve of the shattered side. Then, we put the missing outer profile in place, using a stable fill material to bridge the gap between the outer edge and the interior of the break line.
There’s only so much that can be accomplished in a week, and by the end of our trip Andy and I had just begun filling the remaining losses. The pharmacy jar will be waiting for another team of students next summer, who will take it to completion by disguising the cracks and losses associated with the earthquake damage.
Somehow, on top of our work with the pharmacy jar, we managed to visit six museums and churches! And, of course, we ate plenty of delicious pizza, pasta, and gelato. I’m so grateful for the opportunity to work at the Villa this summer, and I’m excited to return in future years.
by Tessa de Alarcon
So I have written before about desalination to stabilize ceramics with soluble salts, but this time I’m going out into the world, and setting up a desalination station for the Naxcivan Archaeological Project in Azerbaijan.
I had been given a heads up from colleagues Brittany Dolph Dinneen (the previous conservator on site) and Jennifer Swerida (project registrar), that soluble salts may be an issue with the ceramics from the project’s excavations. Salts can be tricky to identify with freshly excavated material, as the ceramic vessels won’t have visible issues until a while after their excavation; once the salts from the burial environment have had time to go through a few cycles of crystallization and deliquescence.
Here at on the Naxcivan Archaeological project, the salts are mostly manifesting as a white haze over the surface of ceramics.
A few are also showing clear crystallization, but the hazing has been the more frequent symptom of the salt problem, especially as this hazing was not observed when they were first excavated.
To confirm that what we were seeing was in fact soluble salts, I poultice the surface.
Once the cotton poultice was dry, I removed it from the surface, re-wet and checked the conductivity, and tested it for nitrates and chlorides with test strips (there are lots of other types of soluble salts, but these are two common ones that are easy to test for). The results were positive, and as you can see the poultice also removed the white haze clearly showing how soluble these salts are.
The next step is getting the water, and while we used to use a similar system at the museum to make deionized water, the scenery is pretty different.
The pot then soaked for a day, while I checked the conductivity until it reached the end point of the desalination process.
Once it was removed from the water I rinsed it with fresh clean water, blotted it dry, then left it to air dry.
Finally, here is the bowl after desalination. As you can see it is now white haze free. Most importantly, it can now be handed over to the Naxcivan Museum with no risk of damage from ongoing salt cycles.
As a final note, it has not been all work, I did get to hike up to the current excavation and I wanted to end on this photo taken from the site, as Azerbaijan is stunning, and I can’t resist the opportunity to share.