APPEAR Project – Reflectance Transformation Imaging of the Fayum Mummy Portraits

Posted on March 28, 2016 by mollygleeson

Update – this post contains outdated language.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.

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.

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.

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.

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.

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

Posted on March 11, 2016 by mollygleeson

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.

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.

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.

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

Posted on March 10, 2016 by mollygleeson

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

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.

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:

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:

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:

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

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

In the Artifact Lab

Monthly Archives: March 2016

APPEAR Project – Reflectance Transformation Imaging of the Fayum Mummy Portraits

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

Animal mummies: contents revealed part II