Shades of the Past

By Julia Commander, Jessica Betz Abel, and Anna O’Neill

We’ve shared a few insights into the monumental limestone we’ve been treating at our Conservation Lab Annex (CLA). You may have noticed a consistent color scheme: tan. The surfaces of the doorways are intricately carved and decorated with faience inlay, although we mainly see a variety of neutral tones.

Doorway 1 in the lab

To get a sense of how these architectural elements would have looked when they were made in Memphis, Egypt around 1213–1203 BCE, it helps to understand the materials and their state of deterioration. Luckily, the Penn Museum Archives has extensive records from the 1920’s Memphis excavations, which provides some further clues about these objects.

Searching through archival materials, we found detailed notes about each object as it was excavated, as well as extensive watercolor illustrations. We can see brilliant colors in the drawings and notes referencing traces of paint and inlay material.

Archival illustrations of Merenptah columns
Archival illustrations of Merenptah columns

We even see that the doorways are illustrated with brilliant blue and teal colors.

Archival illustrations of Merenptah palace doorways
Archival illustrations of Merenptah palace doorways

Some of the illustrations appear to extrapolate data from small traces of material. Do these colorful illustrations line up with what we’re seeing now in the material itself?

To explore a little further, we brought the Crimescope out to CLA to investigate using multispectral imaging. This technique has been discussed on the blog before, and we were particularly interested in infrared (IR) imaging of the faience inlay. While there are different types of faience material, some types related to Egyptian blue pigment produce the same luminescent response induced by visible light.

Searching for IR luminescence pointed us to a tiny area of inlay in the upper corner lintel fragment. The tip of one stripe glowed brightly, which corresponds to a pale green color that’s visible in normal lighting.

Visible light (VIS)
Visible-induced infrared luminescence (VIL)
Detail with VIS/VIL overlay

This result suggests that we’re seeing a deteriorated state of formerly bright blue/green/teal faience. While we did not see every trace of the degraded inlay light up in infrared imaging, this small hint corroborates what we’re seeing in the archival illustrations.

We plan to continue using multispectral imaging to explore decorated surfaces when we’re back at CLA. Stay tuned!

Ptah-Sokar-Osiris and Treating Painted Surfaces

Julia Commander is a third-year graduate student in the Winterthur/University of Delaware Program in Art Conservation. She is currently completing a curriculum internship at the Penn Museum.

As a conservation intern working in the Artifact Lab, I was able to go shopping through shelves of Egyptian objects and scope out interesting treatment projects. A painted wood statue, depicting the composite god Ptah-Sokar-Osiris, immediately caught my eye. The figure has intricate painted designs decorating the mummiform figure and its base, as well as gilded details in the face and headdress.

Ptah Sokar Osiris Statue, L-55-29A-C

L-55-29C, detail of paint and gilding

High-status burials in 19th dynasty Egypt often included this type of mummiform statue. Comparable examples of the popular object type exist in collections worldwide, such as the British Museum and the Metropolitan Museum of Art. Common characteristics include carved wood, a preparatory gesso layer, polychrome design, and in some cases, a coating of varnish. Ptah-Sokar-Osiris statues also frequently feature small compartments carved into the wood figure or base. These cavities could contain small papyrus scrolls or textile wrappings. While examining the object with this in mind, I noticed a faint rectangular shape on the reverse of the figure’s head.

X-radiography, a non-destructive imaging technique that helps clarify construction details, was perfectly suited for the question of the compartment. Without disturbing the delicate painted surface, we were able to observe that a rectangular cavity is in fact cut into the head of the figure. Although the cavity appears to be empty, this interesting construction detail is consistent with similar Ptah-Sokar-Osiris figures.

L-55-29A detail (left) and X-radiograph (right). Image captured from 55 kV, 2 mA, and 6 second exposure.

The statue has several condition issues, such as actively flaking paint and significant darkening over the front surface. Additionally, the figure is unable to stand upright in the base, and the components do not fit together securely. Upcoming treatment aims to address these issues, and I will be searching for the right approach to cleaning and consolidation. The complex surface made of wood, gesso, and paint will require detailed testing to find appropriate solutions.

To further investigate painted surfaces and possible coatings, I used multispectral imaging (MSI), which incorporates multiple light sources to reveal details that cannot be seen in visible light. Interesting findings included the presence of Egyptian blue in the figure’s wig and broad collar, as well as the headdress. This pigment shows up in visible-induced infrared luminescence and is easily distinguishable from surrounding pigments.

Detail of multispectral imaging, highlighting Egyptian blue pigment. Normal light (top), visible-induced infrared luminescence (center) with Egyptian blue shown in white, and false color image (bottom) with Egyptian blue shown in red.

Learning more about the object’s structure and surface will help inform treatment decisions about this complex figure. Check back to see what else we learn and how treatment will proceed!

A Complete View and a Complete Treatment: Conservation of the Roman Period Mummy Mask

After using humidification and four extra hands, the mask is now unfolded! This complete view of the object provides us a wonderful opportunity to look at the materials used in construction and allowed treatment to finally move forward.

Before jumping into treatment, I had the opportunity to perform Multispectral Imaging (MSI) on the mask, allowing us to analyze some of the pigments non-destructively and with great results.

E2462. From left to right: Visible light, Ultraviolet illumination, Visible induced IR luminescence

From left to right: Visible light, Ultraviolet illumination, Visible induced IR luminescence

Under ultraviolet illumination, a bright pink fluorescence was visible (middle), indicating the use of a madder lake pigment in the cheeks and to accentuate the face and hands. I also used visible induced IR luminescence to pinpoint the use of Egyptian Blue pigment in the crown, jewelry, and green leaves (right, Egyptian Blue highlighted in pink). This is a material commonly found in Roman period Egyptian artifacts.

In addition to finding out some of the materials used, I also completed full documentation of the object. Although some of the surface is still intact, the paint layer is in poor condition with areas of flaking and powdering. There is also a large loss to the textile along with some smaller tears and holes.

E2462 During treatment detail of flaking paint

E2462 During treatment detail of flaking paint

As my first order of business, the paint needed to be stabilized. This paint, like many other Egyptian painted surfaces, is sensitive to water and adhesives can cause staining and darkening. This meant a lot of testing was required to find the perfect adhesive for the job.

Using both testing panels and small, discrete areas of the surface, I tested adhesives until I found funori, a seaweed-based polysaccharide. This material preserved the matte and light tones of both the paint and ground layers.

Amaris Sturm, summer intern, consolidating surface of E2462

Amaris Sturm, summer intern, consolidating surface of E2462

As treatments usually go, you sometimes get unexpected bumps along the way. As I was consolidating I discovered that the flesh tones in the face and hands were significantly more sensitive to the water-based adhesive. I quickly had to rethink my approach, ultimately using a methyl cellulose in 50:50 ethanol: water for the hands, face, and larger flakes in the yellow framing the face.

Once consolidation was complete, I moved on to the next hurdle: the molded mud plaster mask. A large gap is present between the fragmented mud plaster crown and the textile below. To support the plaster and its mends, I made a removable fill of carved Volara foam and Japanese tissue, all toned with Golden acrylic paints to make the supports more discrete.

Removable fills to support the heavy mud plaster crown in E2462

Removable fills to support the heavy mud plaster crown in E2462

Fragmented, actively shifting, and detached mud plaster was mended with a 40% AYAT in acetone applied by brush and syringe. Unstable and weightbearing cracks and gaps were filled with a 25% AYAT in acetone that was bulked with microballoons and toned with dry pigments. Fill material was applied with syringed, shaped with a brush and wooden skewer, and  smoothed with a little bit of acetone. A thin toning layer of acrylic paint was applied to fills to make them a warmer tone, but still distinguishable from original material.

Filling compromised gaps on E2462

Filling compromised gaps on E2462

And with that, the treatment is complete! The mask is now stable and will be returned to storage safe and sound.

E2462 Before treatment (left) and After treatment (left)

E2462 Before treatment (left) and after treatment (right)

  • Amaris Sturm is a second-year graduate student in the Winterthur/ University of Delaware Program in Art Conservation. She recently completed her summer internship in the Penn Museum’s conservation labs.

Examination and treatment of a cartonnage pectoral

We have had this object in the collection since 1890:

E352, overall before treatment

E352, overall before treatment

This painted cartonnage pectoral (E352) was made as a covering for the chest of a mummy, and dates to the Ptolemaic Period (ca. 200 BCE). We don’t have the mummy or any other items from the person’s burial, so we don’t know anything about who this belongs to other than that they were buried with this beautiful piece (and likely an equally nice mask, and leg and foot coverings).

This artifact was previously on display in our Secrets and Science gallery and is now in the lab for conservation treatment. It was displayed vertically for over three decades, but since it has come into the lab, we have removed it from the old mount to allow for a full examination, documentation, and treatment.

Multispectral imaging allowed us to identify the Egyptian blue paint used for all of the blue decoration:

An overall image of the pectoral in visible light (left) and a visible-induced IR luminescence image, where the Egyptian blue pigment appears white

An overall image of the pectoral in visible light (left) and a visible-induced IR luminescence image, where the Egyptian blue pigment appears white (right), and everything else is black

We have written about the unique luminescence of Egyptian blue before on this blog, and in the image on the right, above, we can clearly see where it was used to decorate this pectoral.

Conservation treatment so far has included consolidation of the flaking paint with methyl cellulose, carried out under the binocular microscope.

A detail of the pectoral, 7.5X magnification

A detail of the pectoral as viewed through the microscope, 7.5X magnification

I have also been filling small losses with a mixture of Klucel G and glass microballoons, and backing weak areas with Japanese tissue paper.

Here is a link to a mini-slideshow that shows a small section of the cartonnage under 7.5X magnification (the same section seen in the image above). The slidehow shows how I filled a tiny hole with the Klucel mixture, which then allowed me to readhere a tiny fragment of red paint. The change is subtle – see if you can spot where I reattached the paint flake!


APPEAR Project – Multispectral Imaging on the Fayum Mummy Portraits

Hi! This is Eve Mayberger with an update on the Ancient Panel Painting: Examination, Analysis, and Research (APPEAR) project (see earlier post here). I am happy to report that I have completed multispectral imaging (MSI) for the three Fayum mummy portraits. The In the Artifact Lab blog has talked about MSI in several previous posts here and here. MSI is a helpful technique that uses specific frequencies across the electromagnetic spectrum to differentiate and sometimes identify materials.


APPEAR Project, Portrait of a Young Man (E16213)                                                                          Visible (VIS) image. Captured with a Nikon D5200, modified by replacing the hot mirror filter with a glass custom full spectrum filter, B+W UV-IR cut filter (#486 MRC), and incandescent photo light source

Although I took full sets of MSI images for all three mummy portraits, I am only going to share a few images of the Portrait of a Young Man (E16213) which proved particularly interesting. The first step of MSI imaging is to take a normal visible light photo using a modified digital camera and appropriate filters. The object and camera setup must remain unchanged throughout the entire process. Only the light source and camera filters change.


APPEAR Project, Portrait of a Young Man (E16213)                                                                   Ultraviolet visible fluorescence (UVF). Captured with a Nikon D5200, modified by replacing the hot mirror filter with a glass custom full spectrum filter, B+W UV-IR cut filter (#486 MRC), and SPEX Mini CrimeScope 300-400 nm light source.

The ultraviolet visible fluorescence (UVF) image confirms that the wooden panel has been previously repaired. The restored area has a different fluorescence than the surrounding wood (see annotation). I had noticed that the paint in this area was handled differently and noted that it could be a later addition. The UVF image supports this idea.


APPEAR Project, Portrait of a Young Man (E16213)                                                                         Visible-induced visible luminescence (VIVL) image. Captured with a Nikon D5200, modified by replacing the hot mirror filter with a glass custom full spectrum filter, B+W UV-IR cut filter (#486 MRC), Tiffen red camera filter (23A), and SPEX Mini CrimeScope 535 nm light source.

The most unexpected observation was seen in the visible-induced visible luminescence (VIVL) image captured with a 535 nm light source. The filter gives the image the overall red coloring. Notice that the outline of the figure has been etched into the paint. This demarcation of space was completely undetected under other light sources. This technique was not observed on the other two mummy portraits (E16212 and E16214) at the Penn Museum. I am curious to see if other institutions participating in the APPEAR project have portraits with hidden outlines around their figures.

Be sure to visit the blog in the upcoming weeks to read more about the APPEAR project!

Eve Mayberger, Curriculum Intern

Exploring the painted surface of three coffin fragments

Last week, I wrote about x-raying the fragments of a painted wooden coffin, as part of the conservation treatment. The radiographs helped us see what is under the painted surface. We then turned to the painted surface itself. Through cleaning, we revealed how beautiful and well-preserved the decoration is. I described the cleaning process (and linked to a short video showing the process!) in a previous post.


E12617A-C coffin fragments before (left) and after (right) cleaning

While it was impossible to see the full range of colors on the boards before cleaning, after cleaning we could see that there were several different colors used to decorate the surface, including two different yellows, red, green, black, and paint that appears black but where it is abraded/damaged looks blue. After much experience working on ancient Egyptian painted wooden artifacts, I knew enough to suspect that some of the paint that appears black is actually Egyptian blue.

It appears that there is a lot of black paint here, but not all of this paint was originally black. The yellow arrows point to black paint while the red arrows point to areas that I believe were originally blue.

It appears that there is a lot of black paint here, but not all of this paint was originally black. The yellow arrows point to black paint while the red arrows point to areas that were originally blue.

If you’ve been reading our blog, you are probably very familiar with one of our favorite photography techniques for Egyptian material, visible-induced infrared luminescence imaging. I have written about it previously, where I explain the process and the equipment we use (follow this link to the post).

Sure enough, it worked beautifully to confirm, and to allow us to see the Egyptian blue on this object:


Image of the coffin boards in normal light (left), Visible-induced infrared luminescence image (center), False color image (right). Click on the image to see a full-screen version.

All of the darkened/altered Egyptian blue shows up as bright white in the center image above, and the red areas in the false color image on the right help to further visualize where the blue is in relation to the rest of the painted design. Gotta love this technique!

So that’s great for determining the presence and location of Egyptian blue. But what about some of the other colors? I was particularly curious about the two different yellows and the green. In the case of the yellows, are they two different pigments? And as for the green, which pigment(s) were used to produce this color? Without (for the moment – more about that later) knowing the exact time period of this object, I knew there could be at least a couple different options, including Egyptian green (or green frit), and green earth.

To gather more information about these pigments, I carried out portable x-ray fluorescence analysis (pXRF) in select areas on the boards. I collected data from the following areas, marked with colored X’s in the image below:

pXRF analysis locations, with elements detected listed in order of peak height, from large to small

pXRF analysis locations, with elements detected listed in order of relative peak height, from large to small

As you can see, I labeled the image with the findings from the pXRF analysis. It looks like the two different yellows are indeed two different pigments: the darker, more orange-yellow paint contains primarily calcium and iron, suggesting that this is an ochre, while the brighter yellow paint contains calcium, arsenic, and iron. The relatively large amount of arsenic suggests that this yellow was produced using orpiment (arsenic sulfide).

The green paint also contains arsenic, as well as calcium, copper, and iron. So it appears that the green was produced by mixing an arsenic-containing material (orpiment?) with a copper-containing pigment. Due to the lack of any visible-induced IR luminescence in the green areas, I don’t think that these areas could contain any Egyptian blue, so perhaps the green was made by mixing orpiment with Egyptian green. And as you can see, the blue paint does not contain any arsenic, but does contain calcium, copper, and iron, which we expect to find in areas painted with Egyptian blue. Further analysis will be necessary to determine exactly which pigments were used in the yellow and green areas, but we have discovered a lot using these completely non-invasive techniques!

In my next post about this object, I hope to write about the translation and interpretation, for which I’ll need to consult with the museum’s Egyptologists. In the meantime, if you’d like to learn more about green pigments on ancient Egyptian objects, and more applications of multispectral imaging on Egyptian objects, check out this really great video presentation by Kelsey Museum Conservator Carrie Roberts (originally presented at the 2014 ASOR Annual Meeting):

Green Pigments: Exploring Changing in the Egyptian Pigment Palette from the Late to Roman Periods through Multispectral Imaging and Technical Analysis

Multispectral imaging of Wilfred/a’s cartonnage

E12328B_4viewsWhat you see above are 4 different images of our mummy Wilfred/a’s cartonnage. Each image represents a different way of looking at the cartonnage, and assists us in better understanding this object. But what are we seeing in these images, and how did we produce them? (If you have been following this blog, or our museum blog, these types of images may be familiar to you, since we have used these techniques to look at other objects, including a painted wooden shabti box. But every object is different, and in this case, I’ve learned something new that I’ve never seen before, so read on to learn more!)

Let’s start with the image in the upper left – this is easy.


Visible image. Captured with a Nikon D5200, modified by replacing the hot mirror filter with a glass custom full spectrum filter, with a B+W UV-IR-cut filter & incandescent photo light source.

This is a photograph taken in normal (visible) light with a digital camera. This image represents what you see when you look at the object here in the Artifact Lab. We see that the surface of the cartonnage has a design painted in many different colors, and that there are some residues on the painted surface in areas. There is a lot that we can learn about this object just by looking at it in visible light, but what we cannot do is confidently identify the pigments used. So in this case, multispectral imaging comes in very handy. Let’s take a look at the next image.


Visible induced IR luminescence image. Captured with Nikon D5200 modified full spectrum camera, #87C filter, Crimescope 600nm light source.

This is an image of the exact same view of the object, but it was captured using our modified digital camera with a #87C IR filter, using our SPEX Mimi Crimescope with the 600nm filter as a light source. With this technique, we can clearly identify that Egyptian blue was used in the areas that appear bright white, because these areas are showing visible-induced IR luminescence (in other words, they emit infrared light when excited with visible light). No other pigment used by the ancient Egyptians has this property, so we can say with certainty that these areas are painted with Egyptian blue. To better visualize these areas (since the rest of the image is nearly black) we can use the image captured in visible light and the above image to create a false color image.

False color image of the cartonnage created in Photoshop, where the areas painted with Egyptian blue appear red.

False color image of the cartonnage created in Photoshop, where the areas painted with Egyptian blue appear red.

The false color image shows us the luminescent (Egyptian blue) areas in red. If you look closely, you’ll be able to see that the red areas are slightly shifted, due to the fact that we probably bumped the camera in between shots. But you get the idea.

Finally, I wanted to see what we could learn about the cartonnage by looking at it under other wavelengths of light with the Crimescope. I was expecting that we’d probably be able to better visualize the old adhesive used to join the cartonnage fragments in the past, and maybe better understand the residues on the surface. But when we looked at it with the 300-400nm filter (with a peak emission of 365nm), this is what we saw:

UV visible fluorescence image, captured with a Nikon D5200 modified full spectrum camera with B+W UV-IR-cut filter, using the Mini Crimescope 300-400nm filter.

UV visible fluorescence image. Captured with a Nikon D5200 modified full spectrum camera with B+W UV-IR-cut filter, using the Mini Crimescope 300-400nm filter.

In this image, the areas that stand out the most are the areas fluorescing a bright orange-pink color, which appear pink in visible light. I had never seen this before and wasn’t exactly sure what this meant, but after looking into it a bit, I believe that this fluorescence indicates that the pink areas were painted with madder, a dyestuff obtained from the roots of the madder plant. Madder has been identified as being used in ancient Egypt to create pink pigments for painting, and is known for having a characteristic pinkish-orange UV fluorescence, which is how I would characterize what we’re seeing in the above image. There are other ways we could try to confirm this, but this was an exciting, and unexpected observation!

* Special thanks to conservation intern Yan Ling and Conservator Tessa de Alarcon for their help with capturing and processing these images.

Glowing in the dark: multispectral imaging and Egyptian blue

There is something I’ve mentioned before on this blog, but never actually shown, and that is the ability to “see” Egyptian blue on objects using multispectral imaging. On many objects Egyptian blue is very well-preserved, so there is no need for special examination techniques in order to spot it. But there are cases in which being able to accurately identify this pigment is important. Sometimes Egyptian blue deteriorates either by changing color (to green or black) or by becoming lost altogether, making it difficult to know which areas may have originally been blue, or if blue was used at all.

And then there are objects like this one:

Front view of the shabti box in normal lighting conditions

Front view of the shabti box in normal lighting conditions

You’ve seen it before, it’s our painted wooden shabti box. I have been working on the treatment of this box for awhile now, mostly to stabilize the flaking paint and varnish. And this thick, orange-yellow varnish, which we believe is original, and is pistacia resin, makes it difficult to see the painted surface, both the details and the colors. While I could see that there is some green and possibly blue paint on this box, between deterioration of the paint and/or pigment, and the thick application of pistacia resin, I couldn’t say for sure which areas may have originally been painted blue…until now…

Taking advantage of the fact that Egyptian blue has luminescent properties when illuminated with visible light and captured in infrared, we can detect where Egyptian blue was applied. And wow, look at these results:

Visible-induced IR luminescence image of the shabti box. Light source: SPEX Mini Crimescope with 600nm band-pass filter. Captured with a Nikon D5200 modified camera with an IR 87C filter.

Visible-induced IR luminescence image of the shabti box. Light source: SPEX Mini Crimescope with 600nm band pass filter. Captured with a Nikon D5200 modified camera with an IR 87C filter.

This is the same surface of the shabti box seen in the first photo, but zoomed in a bit, and taken under different lighting conditions and captured with a different camera. The areas that appear white are where Egyptian blue was applied. Because everything else pretty much disappears on the box in this image, to better visualize where the Egyptian blue is in relation to other details, we created a false-color image in Photoshop:

False color image of the shabti box. The areas painted with Egyptian blue appear red.

False color image of the shabti box. The areas painted with Egyptian blue appear red.

In this false color image, the areas that appear red are where the Egyptian blue was applied. It’s not perfect (you can see that the bands in the hair of the figure on the right don’t really show up) but we could play around with the photographs a bit to improve this.

We did this imaging on all surfaces of the box, and on the box lids. Here is a regular photo, a visible-induced IR luminescence photo, and a false color image of one of the box lids, also showing lots of Egyptian blue:

Shabti box lid, normal light

Shabti box lid, normal light

Visible-induced IR luminescence photograph

Visible-induced IR luminescence photograph (areas in white = Egyptian blue)

False color image (areas in red = Egyptian blue)

False color image (areas in red = Egyptian blue)

You can use any regular/visible light source to produce the luminescence, but in this case, we used our fancy-schmancy new Mini Crimescope, which was developed for forensic work, but is useful to us because it allows us to examine objects under specific wavelengths of UV and visible light. We found that using a peak emission 600nm light source worked best for the excitation of the Egyptian blue.

In order to “see” the luminescence, we have to capture images using a modified digital camera, with an 87C IR filter.

In summary, we’re having lots of fun with our new equipment, and finding that these Egyptian objects are perfect subjects for learning how to use the Crimescope and the modified camera, because they produce such great, dramatic images.