We’ve had a few posts (this one by Chelsea Kim and this one by Christy Ching) on creating 3D models using photogrammetry, and I thought I’d give some examples of what we are doing with that data once it’s collected. For some objects we are creating ortho-mosaics and these 2D images are going into reports as after treatment images as well as going into the catalogue model as record photography that also shows up in the online collection database. This wooden coffin 2017-20-1.3 is an example of this type of imaging.
For other objects we are also producing ortho-mosaics, but they are before treatment images. For example with E641 a wall painting that was previously on display.
The wall painting is currently in two sections and each one has been imaged separately. These before treatment images have been used to create condition maps.
The maps go into our reports and help provide visual documentation to support our written reports. For large objects, these kinds of condition maps are often easier to understand than written descriptions and can provide more precise information on the location of specific condition issues. Here you can see the condition map for E641. The map is not yet complete, I am still working on documenting one of the sections but I have combined the two maps into one image so you can see what that process looks like.
The models can also be used to show surface distortion, so here in this screen shot of the 3D model of E641 you can see planar distortions in the wall painting where the fragments are not aligned. There may be a variety of causes leading to this distortion including poor alignment during the previous reconstruction or they may be the result of lifting/separation of the original material from its current modern backing.
I am currently working on learning how to create a 2D false color image where the colors reflect depth, so that we can have these planar distortions documented in 2D as well as being able to see them in the model.
So all together, this data is being used to document both the final condition of objects after treatment, as well as to document them before treatment. The models are also useful tools to assess complex condition issues and are valuable for evaluating next steps. For example, our current plan is to remove the wall painting from it’s current modern backing and put it on a new one. Our hope is to correct some of these planar distortions as a part of that process, and this model as well as one we make after treatment will be useful for evaluating the efficacy of the treatment and provide a base line for assessing its condition in the future.
Typically, at the Penn Museum when we are working on objects, even for display, we prioritize stability over aesthetics. This means that we are often do less cosmetic work than would be done at an art museum when it comes to putting in fills and toning out areas of loss. However, I recently undertook a project where I went further than I usually do to recreate lost material. This blog post is going to walk through why that decision was made in this case as well as some of the mysteries that I found along the way
The object in this case is an Egyptian cartonnage mask E1019. When it entered the lab it had a lot of condition issues, including the top of the head was partially crushed, it had been heavily treated before, and it was missing the inlays for its eyes and eyebrows. The missing eye inlays had been giving many visitors to the lab the creeps as the mask appeared to have dark empty eye sockets. Because of this, from the start I had been polling to my colleagues about what level of repair I should do to reduce the distraction of the missing inlays. I was not at this point considering replacing them, but was instead thinking about maybe toning out some of the other losses on the cheek to draw less attention to the eyes.
When it first entered the lab the mask was being tracked as E17632 but over the course of the treatment, I found a different accession number on the interior, E1019. With the help of our curators, we were able to piece together that E1019 was the original accession number, and E17632 had been assigned to it later. When I looked up the record for E1019 in the museum collection database, I found the record included two eye inlays! I was so hopeful that this would mean that I could reintegrate two inlays, one into each eye. However, when I reached out to the curators to get more information, I found out that they are two parts of the same eye, the white part of the eye and a pupil/iris.
Well, this left a new set of problems. Especially since you can see here, the white part of the eye was not very white anymore since it was covered with a dark brown substance. I was left with a lot of options, leave the eye inlays out, reintegrate them as they are, or clean them and reintegrate them, and if I reintegrated them should I then also create a replica set for the other eye?
Before making any decisions, I checked to see if they inlays fit the eye sockets in the mask, which they did. The inlays turned out to be for the masks right eye. After that, I spent some time characterizing the dark coating on the white part of the eye inlay. This included UV examination and comparing how the coating fluoresced with the brown modern materials I found on the interior of the mask from previous treatments. The results were not as clear cut as I was hoping. It seems that there is more than one brown substance on the inlay based on the UV examination. With this data in hand, I reached out again to the curators with the options of leaving the eyes out, reintegrating them as is, or cleaning and reintegrating. The curators indicated that they wanted the inlay reintegrated, and that they would like a replica for the missing inlay as well so that she looked even as one eye seemed worse than no eyes. Together we decided to clean the eye inlay, but to keep samples of the substances on the inlay for future analysis.
Once clean, I set about making a copy for the masks left eye to be a close but not identical match. Based on previous experience I decided to make the new inlay set out of a two-part light weight epoxy called Wood Epox as it is easy to shape and can be sanded and carved. To start, I made a paper template of the shape of each inlay. I made sure to mark what I wanted to be the front of each so that the shape would be a mirror image of the original inlay. The white inlay is slightly curved, so I also created a form that would have the same curvature using foam.
Next, I rolled out some sheets of wood epox, and using the paper template trimmed out the shape I needed for both parts of the eye. The pupil/iris part I let set flat, what let the one fore the white of the eye set in the form I had made so that it would have the same curvature as the original. Once cured I sanded them to finish, with the final stages being wet sanding so that the replica inlays would also have a natural gloss.
The final step before assembly and placement in the mask was the paint them to resemble but not exactly match the originals. I used gloss medium for the pupil/iris as this inlay was especially glossy and I could not get that level of gloss with polishing and painting alone.
Finally, here you can see the end results after treatment. You will see though, that I have not attempted to recreate the inlays for the eyebrows. Because we had the one set of eye inlays, I had something to reference for making the replica set of inlays, however, there are still pieces missing which I had no frame of reference for. There were also likely inlays that went around the outside of the eye as well. These and the brows might have been made out of a variety of materials and without the originals for reference, there is no way to be certain about what their color and appearance would have been.
Over the past 18 months, I completed the examination and treatment of over 200 objects for the upcoming exhibit, The Stories We Wear, which will open at the Penn Museum in September 2021. The exhibit focuses on the idea that what is worn on the body tells a narrative about time, place, and culture. Ethnographic and archaeological material from Oceania, Asia, Africa, Europe, and the Americas will be featured. Alongside these objects will be contemporary ensembles with local connections.
One of the most interesting aspects of treating this group of artifacts is the extensive range of materials. I worked with metals such as gold and silver, fabrics made of silk or wool, organic material such as hair and teeth, and different types of wood. For an objects conservator, this was an ideal project to challenge and enrich my skills. Below are examples of the types of materials that came across my workspace in preparation for the exhibit.
Many of the objects in the exhibit that represent the various cultures of Asia are made of silk. Since silk is a fragile and light-sensitive material, these artifacts will be taken off display after a few months and replaced with similar objects to avoid over-exposure to light in the galleries.
This beautiful silk garment is part of the wardrobe of a married Khalkha Mongolian woman. The silk on the padded shoulders had become worn and thin and was torn at the highest points. These areas were covered with toned Japanese tissue. I toned the tissue with acrylic paints to match the surrounding material and slipped it under the edges of the broken fabric.
Another example of remarkable artifacts from central Asia are these 19th century silver hair ornaments worn by the Daur women of Inner Mongolia. These were used to adorn their elaborate hairstyles. When these pieces came to the lab, they were dark with tarnish, and it was difficult to see their details.
In a museum of archaeology and anthropology, tarnish is not often removed from objects, as it is usually considered part of the historic record of the object. In this case, I talked with the curators of the exhibit and we felt it was appropriate to safely remove the tarnish and coat the silver objects to fully reveal their details.
Many cultures around the world valued gold as a symbol of high status. One of several such objects in the exhibit is this gold diadem. The rosettes are believed to have decorated a headdress or garment of an elite Scythian woman. They were mounted on a modern rod in the 20th century. The rosettes are made of gold foil and wire.
One of the petals of the flower on the far right had broken off at some point and was stored with the object. The petal was attached on the back side with Hollytex fabric (a spunbound polyester) and B-72 (an acrylic copolymer in acetone).
OTHER ORGANIC MATERIALS
In addition to silk artifacts, other objects made of plant and animal materials will be on display, such as this weapon made by the I-Kiribati people of the Gilbert Islands. It is constructed of wood, coconut fiber, and shark teeth.
After cleaning the surface with soft brushes, the shark teeth were further cleaned with enzymes and deionized water. To stabilize loose cords and teeth, I added small pieces of cotton thread through the existing holes. The red circles indicate the areas of added thread.
Here is an example of what the shark teeth looked like before and after cleaning on a small dagger.
These are just a sample of the artifacts that will be on display in The Stories We Wear exhibit opening in September 2021. I hope visitors will appreciate the history and craftsmanship of these objects as much as I do.
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
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.
A question we often get asked in the Artifact Lab is, “what is your favorite thing that you have worked on?” Usually I find this question hard to answer because we work on so many different and fascinating objects, but at the moment, it’s a no-brainer. The trumpets from the Democratic Republic of Congo that are slated to go into the new Africa Galleries are by far some of the coolest objects I have ever worked on. As an example, here is AF5211:
After treatment photo of AF5211
This trumpet is carved from elephant ivory (identifiable by the clearly visible Schreger lines).
Detail of AF5211 showing Schreger lines: a feature used to identify elephant ivory
There is some type of reptile skin wrapped around one end and stitched together on the side, and animal fur that literally makes this object look like a rock star.
detail of AF5211 showing the reptile skin and fur
All these details make this object beautiful, but what makes it special is what is hiding beneath the skin. In a few spots where the reptile skin has shifted you can glimpse repairs.
Detail of AF5211 showing plant fiber repairs
The repairs are even more visible from the interior of the object. It seems that at some point, probably when this object was in use, the ivory split. It was then repaired by drilling holes into the ivory and stitching it together. There is also some type of resinous mixture that was put into the join.
Overall view of the interior of AF5211 showing repairs
Detail of the interior of AF5211 showing the repairs
The reptile skin may have been added to both hide the repair and support it so that the object could continue to be used. It is these glimpses of the life of the object that make it so special. It tells not just the story of its craftsmanship but also the people who used it and cared for it.
To see this object in person, visit the new Africa Galleries when they open in November of this year!
The treatment of the two Al’Ubaid Friezes has progressed since the last post. This post is going to focus on what we have been doing with the marching bull frieze (B15880). This frieze is made up of shell pieces for the bulls (probably made from large conch shells) on a background of black stone pieces with copper alloy borders at the top and bottom of the frieze.
B15880, frieze of 6 bulls
The archaeologists who excavated these materials in the 1920’s set the mosaic into plaster over a wooden backing. Overtime, this support had started to flex, causing the plaster to separate from the wood. This lead to movement of the mosaic frieze casing pieces to loosen and detach as well as causing breaks in the stone. Over the years detached pieces were re-adhered using a variety of different adhesives depending on when the work was done.
Diagram of B15880 showing the 1920’s backing materials in relation to the copper, shell, and stone materials of the frieze.
Because of these issues the mosaic has now been removed from the 1920’s support. One of the perks of having the pieces free from the support, is that we can see both sides of each piece. While we knew from the X-ray that in antiquity they had been attached to the original support using copper alloy wire twists, we can know see those twists.
Detail of the shell showing the remnants of a copper alloy twist/fastener
Detail of the stone showing the remnants of a copper alloy twist/fastener
Now we are working to stabilize each individual piece. The shell bulls are in very good shape, so that has just been cleaning to remove the plaster, areas of over-paint, and adhesive residue. The stone pieces are, however, in much worse shape. We have been consolidating them to restore the cohesion of the stone, joining broken fragments, and cleaning to reduce plaster and old adhesives.
Image showing the progress on cleaning and stabilizing the mosaic pieces.
The next step will be to adhere the clean and stable pieces to a new backing with new grouting around them to keep them in place. Exactly what materials we will use and how that will be done is something we are still working on, but here you can see some of the test tiles that we are making to help make that decision!
Test tiles with bone beads and different possible grouting materials.
Update – this post contains outdated language. We no longer use the term “mummy” and instead use “mummified human individuals” to refer to Ancient Egyptian people whose bodies were preserved for the afterlife. To read more about this decision, follow this link.
I didn’t take any photos during the talks, so I have less visual content to share for this post. For ease of sharing the information about the presentations, I’m going to list the talks here, with speakers names, titles, and brief remarks (all of the talks over the 2 days deserve way more attention than I give them here and in my previous post – hopefully a publication will result – see more about this below). Several of the talks had co-authors, but I’m only listing the co-authors names if they were present at the meeting.
“Evolving Attitudes: past and present treatment of Egyptian Collections of the Oriental Institute.” Alison Whyte, Associate Conservator, Oriental Institute. Alison shared many old archival photos which have helped conservators understand old restorations, and make decisions about how to revisit the conservation of objects that have been in their collection for a long time. Alison also shared the project of the guest curator Rozenn Bailleul-LeSuer of the special exhibit “Between Heaven and Earth – Birds in Ancient Egypt“. Rozenn’s work included CT-scanning and making a 3D print of an eagle mummy, and 3D replicas of its skeletal remains. She brought a 3D print of the eagle mummy to show us, but unfortunately it got lost on her way to the conference along with the rest of her luggage! Let’s hope that it eventually turns up.
“Mummy case saved by LEGO: a collaborative approach to conservation of an Ancient Egyptian cartonnage.” Sophie Rowe, Conservator, and Julie Dawson, Senior Assistant Keeper, Conservation, Fitzwillliam Museum, University of Cambridge. I was familiar with this project due to the fact that it was prominently featured in the news last year. This project was a collaboration between conservators and engineering student David Knowles, who designed a structure to support a cartonnage coffin upside-down during treatment, and devised a plan to use LEGO structures to provide long-term support for the coffin from the interior. To the right is an image of the LEGO structure (it looks a little different from the LEGOs we’re all familiar with).
“The importance of technical analysis and research for the conservation and display of archaeological garments.” Anne Kwaspen, Conservator of the Archaeological Textile Collection, Katoen Natie. I had never heard of Katoen Natie before – it is a company based in Antwerp that has invested in collecting art, through a program called HeadquARTers. They have a collection of archaeological textiles from the art market and private collectors. Anne discussed the study and conservation of their Egyptian wool and linen tunics, and their approach to display.
“Problems and possibilities for the Petrie Museum’s pottery display.” Susanna Pancaldo, Senior Conservator, UCL Museums and Collections. Susanna spoke about recent upgrades to the pottery room at the Petrie Museum. Their pottery room has approximately 3400 objects on display in 36 cases, and was suffering from issues with light, extremes in relative humidity and temperature, lack of mounts and damaging mounts, lack of space, and outdated/minimal labels. In 2014 they received funding to make improvements, including new lighting, new interpretive information, the addition of an introductory showcase showing Petrie’s sequence dating technique, and to carry out conservation surveys and treatments, among other things.
“Innovations for the display of Dynastic textiles using existing designs at the Metropolitan Museum of Art.” Emilia Cortes, Conservator, Metropolitan Museum of Art. Emilia’s presentation focused on the remounting of Egyptian textiles on exhibit to allow for easier access. She showed how she was able to modify existing mounts for elaborate, intricate objects, including this incredible floral collar from Tutankhamun’s embalming cache. Her retrofits included the innovative use of food-grade silicone for preventing movement of objects on exhibit.
“King Menkaure in Motion: the metamorphosis of a Monolithic royal sculpture from the Old Kingdom.” Susanne Gansicke, Conservator, Museum of Fine Arts, Boston. Susanne described the monumental task of moving their King Menkaure statue from one gallery to another within the Museum of Fine Arts. With 2 years lead time, they were able to do gamma radiography of the sculpture in the gallery to help prepare and make decisions about the move, which involved setting the statue on a lifting frame, with 12 wheels attached, and then moving it with the assistance of 2 lifts. It was a very thoughtful project and an impressive feat!
“On not exhibiting a corpse: the Mummy Chamber, Brooklyn Museum.” Lisa Bruno, Head Objects Conservator, Brooklyn Museum of Art. In preparation for the museum’s new “Mummy Chamber“, conservators at the Brooklyn Museum worked on 2 unwrapped mummies, Pa-seba-khai-en-ipet and an anonymous man. The anonymous man, who was methodically unwrapped in the late 1950s, with the procedures documented in the book Wrapped for Eternity, was rewrapped in the conservation lab for display. The decision was made not to display the remains of Pa-seba-khai-en-ipet due to his poor condition, and ultimately, because displaying his remains would mean displaying a corpse, not a mummy.
“Reflecting on Egyptian Pigments: the use of Fibre Optic Reflectance Spectroscopy (FORS) for pigment analysis at the Fitzwilliam Museum.” Jennifer Marchant, Antiquities Conservator, and Abigail Granville, Pigment Analyst, Fitzwilliam Museum, University of Cambridge. Jennifer and Abigail discussed their use of FORS to analyze pigments using a FieldSpec 4 spectroradiometer, which measures in the UV/visible/near IR range. They are building their own reference library, and finding that it is useful as an initial non-invasive examination method, and may be used in the examination of varnishes and binding media as well.
“A case for keeping: the life and afterlife of ritual metal statuary in Ancient Egypt.” Deborah Schorsch, Sherman Fairchild Center for Objects Conservation, Metropolitan Museum of Art. Deborah spoke about examples of Egyptian metal statues in collections around the world that show evidence of reworking for various reasons, often for the purpose of the object serving a new ritual function, or removing details in order to retire objects. One example she spoke about at length was the copper and gold Hierakonpolis falcon in the Egyptian Museum in Cairo. This statue had 4 different phases, with new material being added in each phase of its life.
“Bringing it all together In the Artifact Lab: Conservation, research, display, interpretation.” (Me! I spoke about working on Egyptian material and mummies in a public space, and some of the unique interactions and investigations that we have carried out as a result of the working environment.)
“Ancient Worlds: Open data, mobile web, haptics, digital touch.” Stephen Devine, Digital Communications Officer, and Sam Sportun, Collection Care Manager/Senior Conservator, Manchester Museum. Stephen and Sam introduced us all to Haptic technology and how it is being used at the Manchester Museum to allow visitors to “handle” artifacts. They also spoke at length about the importance of mobile technology and the development of an app to allow visitors to explore and provide feedback about their Ancient Worlds exhibit.
Ashmolean Head of Conservation Mark Norman gave the closing remarks, and expressed their interest in producing a publication from the conference. All of the talks were also filmed, and the conference organizers are planning on making the talks available via iTunesU.
I also should mention that there were several posters at the conference, which were presented on a monitor as a slideshow, and the poster presenters were given ipads to share their “posters” during the breaks. I’m sorry to say that I didn’t have a chance to see several of the posters, so I’m hoping this content will be made available in the future as well!
It was a short, but very worthwhile trip to Oxford. I hope to have the opportunity to return soon.