Monthly Archives: December 2017

#Transformation Tuesday ft. The Big Guy

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By: Céline Wachsmuth

It’s #TransformationTuesday! And that means I get to show off a wonderful transformation that happened right in the Lower Egyptian gallery here at the Museum.

Before Treatment Shot of the Big Guy

After Treatment Shot of the Big Guy

Tah-dah! Looks great, doesn’t it? The Big Guy looks so much better. (I affectionately nick-named this block “Big Guy” because it’s the heaviest block on this side of the wall (it weighs approximately 720 pounds). If you’re in need of some context for this project, check out this Kaipure Catch Up)

Though there isn’t much visible difference between these two photos, in terms of the stability of the block’s surface, much has changed. All in all, this treatment took me about two months to complete and it was quite the journey.

I began my treatment by condition mapping the block in Photoshop and then surface cleaning with gentle vacuuming. Once the dirt immediately on the surface had been removed, I used a variety of sponges and erasers to clean the more stubborn grime. In just these first two steps I realized how fragile much of the surface was. Small flakes would break off easily and not always predictably. Swabbing with a cotton swab was no different and in some cases was more problematic. I proceeded slowly and carefully. Once the Big Guy had been safely cleaned, you could really see his brightly painted surface. The colors were more visible, but so were the fragile and lifting areas. I next faced the biggest challenge of this treatment: how to efficiently and effectively stabilize and consolidate the surface.

Photoshop Condition Mapping of the Big Guy

I began stabilizing all the lifted areas by injecting a dilute adhesive under the surface using an insulin syringe. This worked for some areas but caused some of the surrounding surface to darken. If it came in contact with the surface, the needle also had the potential to disturb it and cause a piece to break off. I then tried to apply the adhesive by brush; I saturated the brush with adhesive and gently tapped the exposed stone next to the prepared surface, wicking the adhesive underneath. This worked but had many of the same issues as the syringe. Both application methods would have taken a substantial amount of time, as almost all of the surface was in need of some consolidation. I began to explore other options for effectively consolidating the surface. In speaking with conservators in the department, we decided to try applying the adhesive via spray canister.

Preval Spray System

Before spraying the entire block, we tested it to see how even the spray application would be and if it would cause any darkening or staining. I was very happy with the tests but thoroughly discussed all the potential shortcomings of this application method with Kaipure project supervisor Molly Gleeson. Spraying the adhesive wouldn’t penetrate below the prepared layer and would only provide superficial consolidation. For those areas that were significantly lifted, I went around with a higher percentage of adhesive and used the brush method of application mentioned above. Once I was satisfied those areas had been stabilized, I sprayed a layer of adhesive on the surface, let it dry completely, and then applied a second layer in areas that were still more concerning. The Big Guy was much more stable and happier but you can’t see any evidence of this because the adhesive is clear!

(I bet if you ask him though, he’d tell you he felt much prettier!)

This figure grabbed a bunch of food to celebrate the Big Guy’s transformation! In actuality, this figure is bringing food for the REAL Big Guy, Kaipure

The Big Guy was almost complete but I had one more task to finish before he would be ready to be handled. Many areas of loss had unprotected edges at risk of being lifted off the surface. Take this area for example, there are quite a few spots with unprotected edges ready to break off with added pressure. 

Detail of unprotected edges

To solve this problem, I edged (put up a protective and supportive layer of material around the exposed edge) those spots with Modostuc. Notice the white spots now on his body?

Can you see the white areas?
Detail of area of edging on figure

I went around to the many places on the Big Guy with unprotected edges and did the same thing. Once I was satisfied all edges had been protected, I painted over all of them with watercolors, a process called “inpainting”. And, if I did my job well, you can’t see it!

Can you find the areas of edging?
Detail of inpainting

The Big Guy is now stable and ready to be moved off-site until the next phase of treatment: re-installing him in the Museum with his many brothers and sisters! This is all part of a larger picture of transformation (for more information on the museum Building Transformation Campaign, click here). It’s a transformation inside a transformation! Inception, anyone?

Two weeks ago, conservator Alexis North posted about one of her recent treatments where the before and after treatment photos are indeed worlds apart and more what you might expect from a Transformation Tuesday post (see her post here). However, don’t judge a book by its cover or an object by its treatment photos! Though you can’t always see the changes, rest assured that once an object passes through conservation it has been changed for the better. Stay tuned for more of our exciting (and perhaps surprising!) Transformation Tuesday series posts!

The Kaipure Conservation Project is funded through a generous grant from the American Research Center in Egypt (ARCE) Antiquities Endowment Fund (AEF) which was established though a grant from the United States Agency for International Development (USAID).

Coming clean

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by Alexis North, Williams Project Conservator

The renovation of our Mexico and Central America gallery will involve the conservation and installation of over 200 objects. Some are currently on display in the gallery, but many have never been exhibited before. One of these “new” objects (actually acquired from the World’s Columbian Exposition in Chicago in 1893) is this carved stone figure from Ecuador. It depicts a human man, possibly a king, seated on a throne.

Before treatment views of 12676, a stone figure from Ecuador.

It has an overall dark, somewhat shiny surface. At first glance, it looks like it may have been carved from a smooth black stone like hematite. However, once I was able to look at the figure more closely in the lab, I could tell there was something suspicious about its surface and overall appearance. The surface had a waxy feel, and upon closer inspection, I could see spots of wax on the surface. These waxy areas were very visible under ultraviolet light:

UV fluorescence image of the proper right side of the figure. The bright yellow-white spots are wax.

When I looked at the bottom of the figure, my suspicions were confirmed. Here you can see the bottoms of the feet of the figure and chair, which appear lighter and grey, and much more like stone than the odd waxy sheen of the rest of the surface.

Before treatment image of the bottom of the figure, showing the true surface and appearance of the stone.

I talked to the American section curator, keeper, and other conservators here in the lab, and we all agreed that this type of figure would not have had any sort of surface coating applied during its original use. It is likely that at some point after excavation, the piece was coated to give it more of an even, dark, shiny surface, which was seen as desirable by art dealers and collectors at the time, followed by a wax as a “protective” layer.

In order to prepare this object for display in our new gallery, the old surface coating had to go. It was misrepresentative of the object’s appearance, and the wax was collecting dust and grime. After our incredibly successful gel cleaning workshop with Professor Richard Wolbers, I decided that an emulsion gel would be ideal for removing this old coating.

I started by testing a number of aqueous cleaning solutions in a rigid agar gel. Small punches of gel with each solution were placed on the surface of the figure, and allowed to sit for 20 minutes. The small pores in the agar gel help it act as a sponge, holding the solutions against the surface and pulling the surface coating into the gel using capillary action.

During (left) and after (right) testing different cleaning solutions with a rigid agar gel.

The agar gel samples, after removing them from the figure’s surface.

And the results of my tests were pretty clear! All the solutions tested were successful in removing some of the surface coating (which is unusual!) but Solution A (deionized water with 0.5% citric acid, buffered to a pH of 6.0) clearly pulled the most grime and surface coating away. I performed a second test using Solution A in a xanthan gum gel, which is viscous but not rigid, resists penetration into the surface it is applied to, and has an emulsifying behavior when agitated which helps to pull out and hold on to the material being removed.

I also tested several solvents on the surface, and found that iso-octane would remove the wax, and acetone and benzyl alcohol both cleared some of the grime. I decided to make a xanthan gel mixture utilizing both cleaning Solution A and a combination of iso-octane and benzyl alcohol. This mixture, when tested on the surface, very successfully removed the surface coating better than Solution A on its own, revealing a lighter, gray-green micaceous stone underneath.

The results from testing xanthan gel mixtures by swabbing them on the surface.

Once the cleaning method was identified, it was simply a matter of systematically removing the coating. I worked in sections, by first applying a layer of octamethylcyclotetrasiloxane (D4), a silicone-based solvent which does not mix with water or the solvents used in the gel. The D4 fills the pores of the stone, and acts as a barrier that keeps the gel, solvents, or surface coating from penetrating into the stone during cleaning. Then I brushed on the xanthan gel mixture, and gently agitated it with a paintbrush over the surface to pull up the surface coating. Once the gel had turned a dirty brown, indicating that it pulled up the coating (see below), I removed the gel with cotton swabs and then cleared the area with deionized water. It was an extremely satisfying, if a bit goopy, process.

Left: After the left side of the seat was cleaned using the xanthan gel. Right: The cleared gel, you can see how dirty it got!

And here are some before and after photos of the figure. The difference is so clear! I believe the coating may have been applied to obscure the scratches you can see on the front of the figure, but overall it looks so much better now that the original material is visible.

After treatment images of the figure.

Front view after (left) and before (right) cleaning.

You can see this figure when we open our new Mexico and Central America gallery in late 2018!

Transformation Tuesday

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Inspired by our Building Transformation campaign, we are starting a series on this blog called Transformation Tuesday. At least one Tuesday a month, we will write a post featuring conservation projects underway that are contributing to the Penn Museum’s Building Transformation, along with interesting tidbits that we are learning about the collection and the Museum building as we work.

For instance, we are in the process of fully documenting the architectural elements of the palace of Merenptah currently on display in the Lower Egyptian Gallery, in preparation for the future reinstallation of this material on the 3rd floor of the museum. This includes documentation and research on a variety of levels, and just last week, the palace elements were laser scanned** in order to document them as accurately as possible before they are moved.

Black and white targets placed around the Lower Egyptian Gallery as part of the laser scanning process (left) and the scanning of a column in progress (right)

To supplement the laser scanning, we are creating condition maps of each of the architectural elements. These are big pieces, so it requires us getting up on a lift so that we can examine all surfaces of the columns, gateways, and doorways.

Last week, we began by examining and documenting one of the palace doorways. We always thought that this doorway had been up since 1926 like the rest of the palace, but in the photographs from the opening of the Lower Egyptian Gallery in 1926, this doorway isn’t there!

Lower Egyptian Gallery in 1926 (left) and in 2017 (right). Note that the doorway on the far right in the 2017 image (indicated by the red arrow) is not in the 1926 photo.

We know that the Lower Egyptian Gallery opened on May 19, 1926. So when was that doorway installed? Well, when we got up on the lift to examine it from above, we could see that there were some very minor differences in the way that it was installed, but we also saw a scrap of newspaper stuck between the plaster restoration on one side and the wall.

A piece of newspaper wedged between the wall board and plaster restoration and the wall behind the doorway.

And this piece of newspaper has a date on it! It is a scrap from the Philadelphia Bulletin dated to Thursday July 22, 1926. So it seems that they intended on installing the doorway for the opening, but may have run out of time, and installed it just a couple months later. This isn’t a huge revelation, but it is an example of some of the fun investigating that we do as part of our work to reconstruct the history of our galleries and the objects that are installed in them.

Stay tuned for more Transformation Tuesday blogposts!

**The laser scanning of the palace of Merenptah was funded through a generous grant from the American Research Center in Egypt (ARCE) Antiquities Endowment Fund (AEF) which was established though a grant from the United States Agency for International Development (USAID).