APPEAR Project – Reflectance Transformation Imaging of the Fayum Mummy Portraits

Hi! This is Eve Mayberger with more information about the Ancient Panel Painting: Examination, Analysis, and Research (APPEAR) project. During the past few months, I have been investigating the three Fayum mummy portraits in the Penn Museum with digital photography, multispectral imaging (MSI), portable x-ray fluorescence (pXRF), and x-ray radiography. Recently, I completed reflectance transformation imaging (RTI) on the portraits with the help of Aislinn Smalling (Leventis Foundation Fellow) and Archer Smith (archaeology post-baccalaureate student). I was grateful to have help because RTI data capture is much easier with multiple people.

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APPEAR Project, Capturing RTI data for E16214 with Aislinn Smalling and Archer Smith

RTI is a type of computational photography that uses digital computation instead of optical processes to create new data. The principles of RTI are that the object and camera are placed in fixed positions. The light source (we used a triggered flash) is moved around the object at different angles. To ensure that the flash is at a set distance from the object, we tied a string to the light. Black spheres are included in each photo and the exact light position is determined from the highlight on the reflective spheres. Normally there are between 36-60 images collected to create one RTI data set.

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APPEAR Project, Four (4) out of the forty-eight (48) photos taken for the RTI data set for E16213

The real power of this technique is the interactive RTI Viewer tool which allows the subject to be re-lighted from any direction. Different rending modes can be helpful to bring out certain surface details such as incised designs or impressions. It is important to remember that this technique is only “pseudo 3D” and while it can be very informative on surface characteristics, it is not scalable or measurable.

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APPEAR Project, Screenshot of RTI Viewer for E16213

The results for E16213 were particularly interesting because we were looking to see if the “curls” visible under MSI were visible with RTI. While RTI showed the working techniques characteristic of encaustic painting, no incised lines corresponding with the curls were detected. Perhaps the curls visible with MSI relate to a pigment that had faded to the point where it is no longer visible under normal light. One possibility is that it could be madder but more research is needed to confirm this hypothesis.

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APPEAR Project, Comparison of the curl region with MSI VIVL and RTI for E16213

In a few weeks, I will be presenting my research on the Penn Museum mummy portraits at the interim APPEAR meeting at the British Museum. Be sure to visit the blog in the upcoming weeks to read more about the APPEAR project and my experience in London!

Eve Mayberger, Curriculum Intern

APPEAR Project – X-Ray Radiography of the Fayum Mummy Portraits

Hi! This is Eve Mayberger with more information about the Ancient Panel Painting: Examination, Analysis, and Research (APPEAR) project. During the past few months, I have been investigating the three Fayum mummy portraits in the Penn Museum with digital photography, multispectral imaging (MSI), portable x-ray fluorescence (pXRF), and most recently x-ray radiography.

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APPEAR Project, Processing the x-ray radiographs

X-ray radiography is an incredibly useful technique to understand different materials, manufacturing techniques, later alterations, and condition issues. The x-ray radiograph of the Portrait of a Young Man (E16213) illustrates tool marks characteristic of the encaustic technique. The pigmented wax is worked warm and one can see the individual brush strokes. The background is made with a wide brush while the face is heavily worked with small tools to create the delicate shading in the flesh tones.

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APPEAR Project, Portrait of a Young Man (E16213); Digital photography; Digital x-ray radiography (36 kV 6mA 6s)

X-ray radiography can help record decorative elements that are difficult to see and documented under normal conditions. The gold frame around the Portrait of a Boy (E16212) is ornamented with raised decorations. The sheen of the gold and the later surface alterations make it difficult to see the overall design; however, the decoration is easily discernible on the x-ray radiograph. It is also interesting to note that the wood grain is visible.

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APPEAR Project, Portrait of a Boy (E16212); Digital photography; Digital x-ray radiography with annotation (36 kV 6mA 6s)

Sometimes x-ray radiography can show alterations to the surface or substrate. The Portrait of a Woman (E16214) shows that the artist decided to change the outline of the face. The annotated image highlights how the contours of the of the woman’s face was changed to give her a fuller cheek. Observe that the dark resin circle around the face is not visible in the x-ray radiograph. It is important to remember that not all materials (especially if they are of different densities) can be shown in a single radiographic image.

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APPEAR Project, Portrait of a Woman (E16214); Digital photography; Digital x-ray radiography with annotation (36 kV 6mA 6s)

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

Eve Mayberger, Curriculum Intern

Animal mummies: contents revealed part II

This is a follow-up to my last blogpost, where I posted some side-by-side images of animal mummies and their x-rays. In this post I’m going to explain what we think we’re seeing in the radiographs.

Let’s start with one of the easiest ones:

50-17-1: mummy paired with radiograph

50-17-1: mummy paired with radiograph

This one is really easy. While the mummy is made to look like a cat, we can clearly see that there are no cat remains, or any remains, inside. All we see inside are very small straight pins, which were pushed into the linen wrappings in 1980 to keep them from unraveling. We know this happened in 1980 because it is noted in an old conservation report. A good example of an ancient “fake”!

The next one is also fairly easy to interpret.

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E12438: mummy from the side, paired with radiograph

We thought this was an ibis mummy, and sure enough, we see an entire ibis inside the wrappings. The GIF above highlights the distinctive skull and beak of the ibis in red.

You could say that the next one, which appears to be a crocodile mummy, has a couple extra special surprises inside:

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E17631: mummy from above, paired with radiograph

There are 3 baby crocodiles under the wrappings! The GIF above highlights the 3 skulls in red.

Next we have what appears to be a falcon mummy, but what we see inside is harder to interpret:

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E12441: mummy paired with radiograph

Upon close inspection, we can see 2 separate, and very small birds inside. In the GIF above, the red outlines the skulls and beaks and the blue outlines the bodies. We don’t think that these birds are falcons, or even birds of prey at all. They look much more like doves or pigeons (based on examination of comparative specimens with zooarchaeologist Dr. Kate Moore). It’s possible that this mummy was never meant to represent a falcon at all – the jury is still out on this one.

Lastly, we have the tiniest mummy of the bunch:

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E12435: mummy from the side, paired with radiograph

There is an animal inside, and it looks like its body is upside-down. It is very difficult to make out, but we can see its front teeth and its long tail. This one definitely called for the expertise of Dr. Moore, who brought up some comparative specimens from her collection. Ultimately, it was the teeth that convinced her that what we see inside this little mummy is a shrew.

Dr. Moore holding a tiny shrew skull

Dr. Moore holding a tiny shrew skull

To the ancient Egyptians, the shrew represented the nocturnal side of Horus. Here is a link to an image of a similar shrew mummy in the collection at the Brooklyn Museum.

Our fun with animal mummies never ends! For more information about where these mummies came from, check our their catalog records in our Collections Database:

50-17-1: Cat mummy

E17631: Crocodile mummy

E12441: Falcon mummy

E12438: Ibis mummy

E12435: Shrew mummy

Animal mummies: contents revealed part I

We x-rayed several animal mummies last week.

Here we are checking in on our patient. Isn't this little kitty mummy so cute, just lying there on the x-ray plate?

Here we are checking in on our patient. Isn’t this little kitty mummy so cute, just lying there on the x-ray plate?

Most of these mummies were on display in the Secrets and Science gallery until 2 weeks ago and several of them are going back on display soon. So now is our time to learn as much about them as possible!

We teamed up with Dr. Kate Moore, CAAM teaching specialist and zooarchaeologist, to see if we can figure out what is under the wrappings of these little (and a couple really little) mummies.

I’m going to divide the information about this project into 2 different posts. For this first post, I’m going to show side-by-side images of the some of the mummies and their x-rays, and welcome readers to make some guesses as to what is inside. I’ll follow this post by providing some information on what we think we are seeing, and some outstanding questions we still have.

E12438: mummy from the side, paired with radiograph

E12438: mummy from the side, paired with radiograph

E17631: mummy from above, paired with radiograph

E17631: mummy from above, paired with radiograph

E12441: mummy paired with radiograph

E12441: mummy paired with radiograph

E12435: mummy from the side, paired with radiograph

E12435: mummy from the side, paired with radiograph

50-17-1: mummy paired with radiograph

50-17-1: mummy paired with radiograph

You can find out more information about these little mummies by searching our Collections Database online (and also by looking at our Current in the Lab tab on this blog). We’ll blog about our interpretations soon.

Conservator Alexis North viewing a radiograph down in our x-ray room

Conservator Alexis North viewing a radiograph in our x-ray room

New mummies in the lab (teaser!)

We are working on documenting and examining the mummies and artifacts that came into the lab this week. We’ll be updating the blog as we learn more. In the meantime, we have updated our Currently in the lab page so you can get an idea of what there is to see in here at the moment.

Teaser! This crocodile mummy is one of the newest additions to the lab.

This crocodile mummy (E17631) is one of the newest additions to the lab.

Questions? Comments? Please let us know by starting a discussion at the end of this post. Thanks!

 

Out with the old, in with the…old

Since we opened in September 2012, visitors to the Artifact Lab have become accustomed to this view:

View into the Artifact Lab, with boards from Ahanakht's coffin pointed out with red arrows

View into the Artifact Lab, with boards from Ahanakht’s coffin pointed out with red arrows

The shelves lining the back wall of the lab have been mostly occupied with large cedar boards from the Middle Kingdom outer coffin of Ahanakht. We’ve written about this coffin before here, here, and here, and we’ve spent a lot of time in the lab examining, conserving, and studying the boards, alongside the Curator-in-charge of the Egyptian Section Dr. David Silverman and his graduate student Leah Humphrey.

Conservator Alexis North and Dr. Silverman reviewing details captured through reflectance transformation imaging (RTI)

Conservator Alexis North and Dr. Silverman reviewing details of the boards captured through reflectance transformation imaging (RTI)

Last week, the scenery in here changed quite a bit, as the boards were carefully packed:

Kevin Cahail secures one of the coffin boards to its custom-made palette in preparation for moving off-site

Curatorial Assistant Dr. Kevin Cahail secures one of the coffin boards to its custom-made palette in preparation for moving off-site

Large boards from Ahanakht's coffin packed and ready to be moved off-site

Large boards from Ahanakht’s coffin packed and ready to be moved off-site

Since the boards have been documented and conserved, they are moving off-site temporarily to make room for “new” things to come into the lab. These “new” pieces are actually being deinstalled from our Secrets and Science and Mummy Galleries, in order to retrofit those galleries to ensure that they will be secure during the construction project happening next door at the Hospital of the University of Pennsylvania (HUP).

Views into the Secrets and Science gallery, before deinstallation began

Views into the Secrets and Science gallery, before deinstallation began

Views into the Mummy Gallery, before deinstallation

Views into the Mummy Gallery, before deinstallation

Some of these objects and mummies will go back on display shortly, but need to be examined and conserved first, so they will be worked on in the Artifact Lab in the next few weeks to allow for reinstallation.

Details about the construction project at HUP and how it is affecting our museum have been described in some recent news articles, which you can find by following links that I’ve included at the end of this post.

For a couple days, the shelves in the lab were empty:

Conservator Alexis North working in the Artifact Lab with emptied shelves in the background

Conservator Alexis North working in the Artifact Lab with emptied shelves in the background

but we didn’t waste any time filling them back up again:

Shelves in the Artifact Lab filling up with new things

Shelves in the Artifact Lab filling up with new things

Note, this photo above was taken after day 1 of deinstallation; there will be more coming into the lab in the upcoming days.

We’ll post more about some of these “new” artifacts and mummies as we work on them in the next few weeks.

Penn Museum moves history (carefully) to make way for future

Demolition next door puts Penn Museum on shaky ground

Delicate process of preserving artifacts as things get shaky at UPenn Museum

Moving Marble: Penn Museum prepares for Penn Tower demolition

 

APPEAR Project – Portable X-Ray Fluorescence on the Fayum Mummy Portraits

Hi! This is Eve Mayberger with another update on the Ancient Panel Painting: Examination, Analysis, and Research (APPEAR) project (see earlier posts here and here). I recently investigated the pigments used on the three Fayum mummy portraits with the portable x-ray fluorescence (pXRF). While the pXRF results for all three portraits are interesting, I am going to briefly discuss the findings for the Portrait of a Woman (E16214).

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APPEAR Project, Portrait of a Woman (E16214); Annotation of pXRF test locations

One of the major advantages of pXRF is that it is a non-destructive technique that uses x-rays to identify specific elements. The technique can help to characterize pigments and metal alloy components. It is important to remember that pXRF is a surface technique and will only detect elements present on the surface. I decided to analyze the seven different colors used on the mummy portrait to determine if there are any elemental differences.

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Collecting data with the Brucker pXRF

All the test locations recorded prominent peaks for calcium (Ca), iron (Fe), and lead (Pb). Although there is some variation in peak heights across the test spots, it is important to remember that pXRF is a qualitative not a quantitative technique. See below for a representative spectrum for six out of the seven analyzed locations.

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APPEAR Project, Portrait of a Woman (E16214); Spectrum for sample #2 – forehead; Peaks detected for Ca, Fe, and Pb

The green used to paint the gemstones on the woman’s necklace has an additional peak for copper (Cu). This is not surprising as many greens have a copper component. In ancient Egypt, the greens were generally made with malachite or green earths, or from a mixture of blue and yellow pigments. While malachite is a copper-based compound, more analysis is needed to confidently identify the green pigment used for the gemstones.

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APPEAR Project, Portrait of a Woman (E16214); Spectrum for sample #5 – gemstone on necklace; Peaks detected for Ca, Fe, Pb, and Cu

It should be noted that not all pigments can be identified with pXRF alone. Some organic pigments, such as madder, cannot be detected with pXRF. In addition to using analytical instrumentation, it is also important to know what colorants are expected on specific artifacts to help limit the number of possible pigments.

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

Eve Mayberger, Curriculum Intern

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.

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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.

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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.

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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

APPEAR Project – Fayum Mummy Portraits

Hi! This is Eve Mayberger and I am a curriculum intern from New York University. I am currently spending nine months at the Penn Museum as part of my fourth-year internship. I want to introduce one of the projects I am working on in the Artifact Lab. The Ancient Panel Painting: Examination, Analysis, and Research (APPEAR) project is a Getty Institute initiative to create an international database on Fayum mummy portraits. A website was created to allow different types of analysis and imaging to be uploaded and shared with other institutions participating in the APPEAR project.

The Penn Museum has three Fayum mummy portraits in its collection [E16212, E16213, and E16214]. These portraits date from the Roman period in Egypt and were executed in either encaustic (wax) or tempera. The portraits depict a boy, a young man, and a woman. The figures are painted on thin panels of wood that are adhered together. Remember that wood was a rare and expensive material in ancient Egypt and every tiny piece of wood was valuable.

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APPEAR Project, Portrait of a Boy (E16212)

All three portraits have been repaired at some point in their history. One of my challenges is going to be to differentiate the original materials from later additions. Fortunately, the Penn Museum has the old treatment records that will hopefully be useful to piece together the treatment history of these objects.

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APPEAR Project, Portrait of a Young Man (E16213)

After carefully examining the portraits, I took them down the photography studio in the main conservation lab. These high-resolution photos will be uploaded to the APPEAR website. In the upcoming weeks, I will be using imaging and non-destructive analysis to further investigate these mummy portraits.

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APPEAR Project, Portrait of a Woman (E16214)

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

Eve Mayberger, Curriculum Intern

Progress update on the stola coffin treatment

For the past few weeks, it has been full steam ahead on the treatment of the stola coffin lid. The lid is made of smaller pieces of wood joined together, then covered generously in areas with a thick layer of coarse mud plaster, followed by a thin layer of a finer mud plaster, followed by paint and a varnish. There are also raised details that were built up with gesso before painting.

This large piece of painted mud plaster (detached from the foot of the coffin, seeing on the left) is 11 cm thick.

This large piece of painted mud plaster (detached from the foot of the coffin, seen on the left) is 11 cm thick.

This area of damage clearly shows the wood substrate (green arrow), coarse mud plaster (blue arrow), and finer mud plaster (red arrow).

This area of damage clearly shows the wood substrate (green arrow), coarse mud plaster (blue arrow), and finer mud plaster (red arrow).

The two major condition problems on the coffin are found in the mud plaster layers: the coarse mud plaster has lost cohesion and in many places has separated from the wood below, and the finer mud plaster has also lost cohesion, so much so that it has deteriorated to a fine powder in places. I have spent over 150 hours so far readhering detached plaster, consolidating the powdery plaster, and realigning and stabilizing loose fragments on the coffin. Today I’m posting a few before and after treatment details to show the progress.

Here are before and after details of the top of the head showing an area where I had to readhere some large fragments of painted plaster:

Top of the head before (left), during (center), and after (right) reattaching painted plaster fragments

Top of the head before (left), during (center), and after (right) reattaching painted plaster fragments

Here are before and after details of the left eye showing the consolidation of exposed powdery mud plaster:

Detail of losses near the left eye before, showing powdery mud plaster (left) and after cleaning and consolidation of the mud plaster in the losses

Detail of losses near the left eye before, showing powdery mud plaster (left) and after cleaning and consolidation of the mud plaster in the losses (right)

And here is an area on the side of the head where I found that some fragments were previously attached in incorrect places. They were repaired long ago (with no documentation) with an adhesive that is soluble in warm water. I reversed the old repairs and found the correct locations for the fragments. I’ve outlined the fragments in their incorrect locations in the before treatment image on the right, below:

Detail of treatment on the side of the head before, with misplaced fragments outlined in pink (left), and after respositioning (right)

Detail of treatment on the side of the head before, with misplaced fragments outlined in pink (left), and after respositioning (right)

I still have lots of work to do before the treatment is complete, but I’m making good progress! I hope to be finished with the treatment early in the new year.