APPEAR Project – APPEAR Interim Meeting at the British Museum

Hi! This is Eve Mayberger with an update 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), x-ray radiography, and reflectance transformation imaging (RTI). A few weeks ago, I had the opportunity to travel to London and represent the Penn Museum at the APPEAR interim meeting.

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APPEAR Project, British Museum

The meeting was jointly organized by the Getty and the British Museum. Representatives from invited institutions were asked to present an update on the current research of Fayum mummy portraits in their collections. Although not every participating institution was able to send a representative, there were individuals from the United Kingdom, Europe, and the United States. The group included conservators, conservation scientists, art historians, and artists who were all personally engaged with different aspects of the APPEAR project.

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APPEAR Project, Presentation at the APPEAR interim meeting

For the APPEAR research at the Penn Museum, I talked about our non-destructive analysis, imaging, and outreach initiatives for the three portraits in the collection. I focused on some unusual observations I recorded with MSI on the Portrait of a Young Man (E16213). My presentation was well received and inspired a lively debate about MSI terminology and standardization protocols.

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APPEAR Project, Penn Museum Presentation

Between talks and over meals, I was able to chat with other APPEAR participants about their various institutions and current research initiatives. At the end of the meeting, the British Museum was kind enough to give us an extensive tour of their new conservation labs and scientific research department. It was an amazing experience and I was honored to present our research at the Penn Museum to the larger APPEAR community.

Eve Mayberger, Curriculum Intern

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

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