The treatment of (half of ) a yellow coffin

This week, we finally finished the treatment of the lower half of our 21st/early 22nd Dynasty yellow coffin.

A view of the interior of the coffin before (left) and after (right) conservation treatment.

A view of the interior of the coffin before (left) and after (right) conservation treatment.

The treatment mostly involved cleaning the interior surfaces to remove dust using a soft brush and HEPA-filtered vacuum, and cosmetic sponges. Here’s another view to give you a better sense of just how much grime had accumulated in the interior of the coffin:

A detail of the head of the interior of the coffin before (left) and after (right) conservation treatment.

A detail of the head of the interior of the coffin before (left) and after (right) conservation treatment.

There was also a fair amount of flaking and lifting paint, which needed to be stabilized. We used 1-2% methylcellulose in 50:50 water/ethanol to consolidate flaking paint, and Japanese tissue paper and 5% methylcellulose to fill gaps.

In the course of the treatment, I have also continued to research the significance of the holes drilled into the bottom of the coffin, which can clearly be seen in the overall images at the top of this post, but here is another look:

An overall shot of the coffin bottom, with a detail of 4 of the holes below.

An overall shot of the coffin bottom, with a detail of 4 of the holes.

I’m anxious to start working on the lid of this coffin, which will inevitably provide more information about this object and it’s history. We should be able to bring the lid from storage up to the lab sometime this summer, and I’ll post images of it as soon as it arrives. In the meantime, I have enjoyed researching these types of coffins and finding images of similar ones in other collections (like this one at the Petrie Museum, this one at the Houston Museum of Natural Science, and this “remuddled” coffin at Stanford University) which is helping me gain a better understanding of these coffins and the contexts in which they were made.

Looking inside Nespekashuti

A few weeks ago I introduced you to Nespekashuti, a New Kingdom mummified man who we recently removed from display in our mummy room for conservation treatment. Even though we’ve had Nespekashuti and his coffin since 1893, we have very little information in our database about him. Working on his remains in the Artifact Lab is providing an opportunity to take a much closer look and to learn more about him.

Overall view of Nespekashuti before treatment

Overall view of Nespekashuti before treatment

One of the first things we decided to do was to x-ray his remains using our new digital radiography equipment. Although Nespekashuti looks pretty well-wrapped (despite his teeth being exposed), this is what we see under the wrappings:

X-ray of Nespekashuti (image created by stitching several x-rays together)

X-ray of Nespekashuti (image created by stitching several radiographs together)

As you can see, there are some big empty spaces (areas that are completely black), especially the neck and upper chest area, and there are areas where bones are completely disarticulated and appear to be piled on top of each other. We’re not really sure why this would be, but we have some ideas. Dr. Janet Monge, our physical anthropologist, is currently taking a closer look at the x-ray images in order to draw some conclusions about the bones and their condition, which may help us better understand why they are a bit of a jumbled mess…not unlike another mummy we recently treated and x-rayed, Pinahsi.

In the meantime, I’ve started the conservation treatment, which I’ll be sure to report on as I make progress.

A tiny mystery mummy

Yesterday we x-rayed mummies of 2 extremes: a full-sized human mummy (Nespekashuti), and a tiny mystery mummy:

mystery mummy

This tiny mummy is about 2″ wide and 5″ long, and easily fits into one of my hands.

We already had the x-ray tube warmed up for capturing images of Nespekashuti, so we figured we’d zap this little mummy while we were at it, to find out what is underneath those wrappings. We had lots of guesses, but ultimately, none of us guessed correctly.

Here is one of the x-ray images:

An x-ray image of our tiny mystery mummy

An x-ray image of our tiny mystery mummy

We had 3 conservators in the room when this image popped up on the computer screen, and we were immediately puzzled. Bird? Definitely not. Crocodile? No. Mouse? Nope. Cat? Again, a no. Could it be a…dog? We knew that the 3 of us non-experts couldn’t say anything with any certainly, so we called in the big guns…in the form of zooarchaeologist Dr. Kate Moore, who has helped us with some of our other animal mummies in the past.

Dr. Moore spent some time looking at the images, and then looking at some x-ray images of immature dogs (puppies!). She was troubled by a few things, including the fact that we can’t see any teeth and that the animal appears to have only 1 leg, also the length of the spine and front paws/feet, but ultimately concluded, based on the x-ray images that we captured, that this is indeed a puppy, who died right around the time it was born.

Based on its size, I don’t think any of us expected this tiny mummy to contain a dog, but it’s not surprising that we would have a dog mummy in our collection, since millions have been found in Egypt, notably in the Dog Catacombs of Saqqara. And this isn’t the only puppy mummy in our collection – if you visit the museum, you can see Hapi-puppy on exhibit, displayed at the feet of his owner, Hapi-men, both of which have been CT-scanned. A CT-scan of our newly-discovered puppy mummy would provide greater detail and a better understanding of this tiny animal, and would help make a more certain identification. We’ll be sure to update the blog with any new findings if we are able to do some more imaging.

 

Wilfred/a’s many mysteries

Last week, we moved our mummy Wilfred/a from the Artifact Lab down to our new digital x-ray lab to capture some x-ray images and hopefully get to the bottom of the male/female debate.

Wilfreda after treatment

Wilfred/a after treatment

Above is an overall after treatment image of Wilfred/a. The goal of the treatment was to get this mummy out of the original packing materials, to assess and document the remains, and to house them in a way that they can safely be moved to our x-ray room for imaging, and then returned to storage. If plans are made to exhibit Wilfred/a in the future, further treatment can be carried out at that point, but for now, this mummy is stabilized and will be much more accessible for research.

We were excited to x-ray Wilfred/a’s remains, but while we are used to x-raying ceramics, wooden artifacts, metals, and other types of cultural materials, x-raying human remains is not something that any of us in the conservation department specialize in, so we brought in some experts to help us with this task: Dr. Janet Monge, Keeper and Curator-in-Charge of the Museum’s Physical Anthropology Section, and Dr. Morrie Kricun, Emeritus Professor of Radiology, Hospital of the University of Pennsylvania. In fact, it was Dr. Monge and Dr. Kricun’s initial examination of Wilfred/a’s remains and some old 1932 x-ray radiographs that made us think that this mummy may be female, rather than male.

With the assistance of Dr. Monge and Dr. Kricun, Conservator Tessa de Alarcon and I captured a complete sets of x-ray images of Wilfred/a. And the really cool thing about having a digital system is that we can capture the images in seconds, and see the results immediately. While full interpretation of the images is underway, I will share a couple of the findings that are quite interesting.

First, let’s clear up the debate and start addressing this mummy by the appropriate pronoun. This mummy is female, and therefore we’ll call her Wilfreda from now on (or until someone proposes a new, more appropriate name). Determining that Wilfreda is female was possible by a thorough examination of her pelvis. There are a few other possibly very cool findings related to the fact that she’s female, but I’m going to wait on the full interpretation before sharing any other details about this on the blog.

Secondly, we knew that Wilfreda’s head was missing, but what we didn’t realize was this:

wilfredanofeet

X-ray radiograph of Wilfreda’s lower legs and (missing) feet. Exposure: 65kv 5ma 6 seconds

Her feet are missing! From the outside, it is obvious that the wrappings around the feet were disturbed at some point, but it wasn’t possible to see until these x-rays were taken that the feet are totally gone. In this next image, which we captured to better see the linen wrappings, you can clearly see where the feet would have been:

45kV 5ma 6 seconds

Exposure: 45kv 5ma 6 seconds

The weird thing about this is that her feet were there when the 1932 x-rays were taken:

wilfredaoldxrays

2 different x-ray images captured in 1932, clearly showing the feet of the mummy.

Where have her feet gone? We don’t know. This is now a new mystery.

Just in case any of you are following this blog very closely, and are wondering if the feet could have been lost somewhere inside the old crate (pictured below), the answer is no, but some other things of interest did turn up in there.

wilfredascrate

Buried in the old padding of the crate, we found the following:

Wilfredasbox

  • a Keuffel & Esser Co. 1903 Catalog of drawing materials and surveying instruments
  • 4 tickets that say: “Only for School Children – Not Transferable. Barakat’s Lecture, on BIBLE LANDS, illustrated by ancient curiosities used 1800 years ago, and costumes worn 4000 years ago. ADMIT ____ who will Bring this and Five cents.” (I’ve neglected to write about him on the blog but Wilfreda was originally in the possession of Professor Elias Barakat, who, for about a decade, traveled around the US lecturing about the ancient world, with Wilfreda as one of his “curiosities.” His wife donated Wilfreda to the museum in 1911.)
  • Rubber stamps, for printing announcements, etc., one of them with Barakat’s name
  • small wooden dowels
  • a piece of cartonnage
  • fragments of wood, textile, paper, plant materials, seeds.

Leave it to Wilfreda to keep a few surprises from us. We’ll post more about the x-ray interpretations once we know more, and continue to try to put the pieces of these mysteries together.

A closer look at one of our feathered friends

We have an ibis mummy in the lab, which is revealing itself to us in an unusual way.

Unlike most animal mummies in our collection, we can actually see the ibis’ remains – in this case, its feathers! It is unfortunate that the linen wrappings were damaged in the past, but this damage does provide a unique look under the bandages.

ibiswithfeathers

Ibis mummy, 97-121-19, from Thebes, Late Period (ca. 664-332 BCE).

While x-ray radiography revealed that there is indeed an ibis inside (the beak is a dead giveaway), the feathers provide further clues about this bird that was mummified approximately 2500 years ago.

Radiograph taken from the top down. Exposure information: 35kV, 5mA, 6 seconds. Image enhanced with flash! filter.

Radiograph taken from the top down. Exposure information: 35kV, 5mA, 6 seconds. Image enhanced with flash! filter.

When researching ibis mummies, I read again and again about the African Sacred ibis (Threskiornis aethiopicus) being mummified, but there were other types of ibis in Egypt, including the Glossy ibis (Plegadis falcinellus) and the Northern Bald ibis (Geronticus eremita). I don’t know if evidence has been found that these other types of ibis were mummified, but I do know that I shouldn’t immediately assume that this particular ibis mummy contains the remains of an African Sacred ibis.

So, let’s look at the feathers, and what we can learn from them. The feathers that are exposed appear to be contour feathers that may be part of one of the wings. There are a few completely detached feather fragments in this area, so I was able to take a closer look at one small fragment under the microscope.

ibisfeatherlabeled

Left: ibis feather 7.5X magnification. Right: ibis feather 50X magnification.

The most obvious feature to note, even without a microscope, is the coloration. This feather is white and black. The African Sacred ibis has a very beautiful, distinctive, black and white plumage, so in this case the color alone may be enough to identify species.

If we can’t rely on color, what else can we learn from this feather fragment? Well, we can see that it is part of a pennaceous (rather than plumulaceous, or downy) feather, the parts of which I’ve labeled in the above images. To take an even closer look at these elements, I used our polarizing light microscope and was able to see the tiny hooklets on the barbules, which “zip” the barbules, and therefore the barbs, together.

Ibis feather 100X magnification.

Ibis feather 100X magnification.

The barbules of feathers can be used for identification of species, but usually barbules from plumulaceous feathers are used, as they have a very different and distinct appearance. Unfortunately, I don’t have access to any plumulaceous feathers from this ibis mummy, so this may be as far as I can go at the moment. There are other researchers, both within the field of Egyptology, but mostly in ornithology, who have spent much more time looking at ibis feather structure than I have, and of course there is DNA research, so we may learn more in the future about this ibis mummy and its feathers.

I have a special place in my heart for birds and feathers, since before coming to the Penn Museum, I worked on an extensive project on feather coloration as part of a collaborative research effort between UCLA and the Getty Conservation Institute. Click on the links below to find out more about this work:

A Collaborative Study of California Featherwork

California Featherwork: Considerations for Examination and Preservation

And to learn more about feather structure, start by following this link: The Cornell Lab of Ornithology: All About Birds: Feather Structure

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.

E12328B_visible01_compressed

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.

E12328B_IR01_compressed

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.

Examination and treatment of Wilfred/a

We still haven’t gotten to the bottom of the question of whether our mummy Wilfred is indeed Wilfred or is instead Wilfreda, because there have been a few things to take care of first. In the meantime, I am referring to the mummy as Wilfred/a. Hopefully this person would not be offended by the ambiguity, but we hope to clear this up soon by x-raying the mummy using our new digital x-ray system. Before we can do this, I have been working to stabilize the remains enough to allow them to be moved safely down to our x-ray room. In the process of stabilizing the remains, I have made some observations.

The exposed remains on the upper part of the body, while very fragile and disarticulated, are remarkably well-preserved in areas. The preservation of the hands and arms is particularly notable – the fingernails are intact on the left hand, and it is clear that the arms and hands were wrapped separately with linen as part of the mummification process, due to the presence of linen and impressions of linen on the skin.

A detail of the left hand and arm. Note the presence of fingernails, and the linen and linen impressions, marked on the photo with yellow and red arrows.

A detail of the left hand and arm. Note the presence of fingernails, and the linen and linen impressions, marked on the photo with yellow and red arrows.

Unfortunately, we can also see that there has been damage to the right hand since the 1932 x-rays were taken (Wilfred/a, along with many other mummies in our collection, was x-rayed in 1932 by Dr. J.G. Cohen at the Graduate Hospital). In the old radiograph, it is evident that on the right hand, the thumb is intact, and at least most of the hand and fingers are also intact (the hand is partially cut off on the image). Today, we’re missing the thumb, all of the fingers, and part of the hand – only 3 of the metacarpal bones remain.

Left image: 1932 radiograph, showing arms crossed and right hand intact. Right image: 2015 photograph, showing damage to right hand.

Left image: 1932 radiograph, showing arms crossed and right hand intact. Right image: 2015 photograph, showing damage to right hand.

In my examination of the remains, I did not locate any detached elements from the right hand, but it doesn’t meant that they’re not in there somewhere! We may locate them once we x-ray the remains again.

Also of note is that the arms are crossed over the chest, right over left. From what I have read, the crossed arm position is generally not seen until the New Kingdom, when it is reserved for royalty, until about 600 BCE or later. We think that Wilfred/a dates to the Ptolemaic or Roman period, based on the style of the intact wrappings around the legs.

This mummy was elaborate wrapped with narrow strips of linen, creating a rhomboid pattern.

Wilfred/a’s wrappings are intact from the pelvis down, with narrow strips of linen creating an elaborate rhomboid pattern.

Because Wilfred/a likely dates to this Graeco/Roman period, the arms crossed over the chest do not indicate royalty, necessarily, and may have been to emulate the pose of Osiris (see this article for more information).

Once these observations were documented, I started in on the treatment. Since there are no immediate plans to exhibit Wilfred/a’s remains, I took some measures to stabilize them for the move down to the x-ray room and for eventual return to storage. If we ever do decide to exhibit them, the conservation work to prepare them for display will be much more straightforward now that some of the initial work has been carried out.

After removing Wilfred/a from the mattress (with a little help from my colleagues), I carefully removed all fully detached material and bagged it according to material type. I lightly cleaned the surface of the exposed arms and the intact wrappings on the legs and feet, recovering some insect remains and remnants of old packing materials (like cotton and wood shavings) in the process. I then wrapped the mummy in Tyvek and bolstered the sides of the chest area with pillows made from Tyvek and polyester batting. Wilfred/a is now ready to move onto a rigid support, which we plan to make from archival honeycomb board specially purchased for this project.

Wilfred/a, pictured here after treatment, is now almost ready to be moved down to our x-ray room.

Wilfred/a, pictured here after treatment, is now almost ready to be moved down to our x-ray room.

 

Wilfred/a’s cartonnage

While we prepare our mummy Wilfred/a to be x-rayed, we are simultaneously working on fragments of cartonnage that may belong to the him/her.

Cartonnage fragments before treatment, in no particular arrangement or orientation

Cartonnage fragments before treatment, in no particular arrangement or orientation

There are 35 pieces, some of which are assemblages of multiple fragments mended together, plus some very small fragments in a ziploc bag.

The cartonnage consists of 2 layers of linen adhered together, with a fine plaster coating on one side, which is painted, and a thinner, more coarse layer of plaster on the other side. Here is a magnified image of one of the fragments, and an image of it in cross-section:

The painted side of one fragment of cartonnage (left) and the same fragment in cross-section (right), 7.5X magnification

The painted side of one fragment of cartonnage (left) and the same fragment in cross-section (right), 7.5X magnification

It is unclear what these fragments originally belonged to. They definitely do not make up an entire object, and they are mostly flat. We can see that there are at least 3 figures depicted in the painted decoration, but we’re still in the process of trying to piece together the rest of the design, and trying to figure out which pieces join together.

Pre-program intern Yan Ling examines the cartonnage fragments with the aid of an optivisor.

Pre-program intern Yan Ling examines the cartonnage fragments with the aid of an optivisor.

Yan Ling, our pre-program intern and an art conservation undergraduate from the University of Delaware, is helping me document the fragments. As part of our examination process, we will be looking at the fragments with our Mini Crimescope, and we’ll post anything interesting that we find on here soon.

 

Wilfred or Wilfreda?

So, there has been some controversy over the fact that our mummy Wilfred is being referred to by a man’s name because there is some suspicion that this mummy may in fact be female!

Just before Thanksgiving, Dr. Janet Monge, Keeper and Curator-in-Charge of the Museum’s Physical Anthropology Section, along with colleagues Page Selinsky and Francesca Candilio, took at peek at the mummy and there was a hot debate over some of the features on the pelvis, but they all started leaning toward the conclusion that the mummy may be a woman.

The group huddled around the mummy. Photo by Nina Owczarek, copied from the Museum's Instagram account.

The group huddled around the mummy. Photo by Nina Owczarek, copied from the Museum’s Instagram feed.

The group felt like they needed to see the bones better. One of them (half-jokingly) asked if we could just lift the pelvis out. While we plan to take some new x-rays using our new digital radiography equipment, we have to do some work on the mummy in the lab first. But in the meantime, we can take a look at the x-rays taken in 1932 over at the Hospital of the University of Pennsylvania. The only notes from this old radiographic study say “adult”.

Radiograph of the chest area, showing the crossed arms, ribs, vertebrae.

Radiograph of the chest area, showing the crossed arms, ribs, vertebrae

Radiograph of the pelvis.

Radiograph of the pelvis

Radiograph of the feet.

Radiograph of the feet

Dr. Monge offered to share these images with her colleague Dr. Morrie Kricun, Emeritus Professor of Radiology, Hospital of the University of Pennsylvania. Dr. Kricun was able to manipulate the image of the pelvis to view it as it would look like if it was undisturbed.

Manipulated radiographic image of the mummy's pelvis

Manipulated radiographic image of the mummy’s pelvis

He’s also leaning toward female, but wants to do some additional imaging, which we plan to do soon. I promise to update the blog as soon as we do this! But for now, I feel like I may need to start calling this mummy Wilfreda.

 

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.