Ur Project: February 2015

Deep Pits and Early Burials (Again)
Spotlight on 31-17-403: Uruk Period Skeleton from Ur
Penn Museum’s second rediscovered skeleton

The documentation that led to the rediscovery of an ancient skeleton from Ur in the Penn Museum’s storerooms last year showed that two skeletons had been received in March of 1931. This month we have located the second.

31-17-403 after opening the crate and pulling back the burlap

31-17-403 after opening the crate and pulling back the burlap

Like the first skeleton, this one was originally excavated in a deep pit intended to investigate the earliest levels of the ancient city. The first came from Pit F, nearly 50 feet below the surface of the mound. The second came from Pit Y, around 45 feet down. Overall documentation on the second skeleton is not nearly as complete as the first, however.

The minimal documentation recorded on receipt showed only that one skeleton was ‘stretched’ and the other was ‘flexed.’ The Ubaid period skeleton 31-17-404 is indeed extended, lying on its back with hands at its pelvis. The second skeleton, 31-17-403, is lying on its side with its knees bent and its hands near its mouth. Woolley took several photos of the first skeleton and the process of waxing it, but he did not report preserving a second skeleton. He did, however, take a field photograph of what he called the best preserved example of the flexed burial type. This was the very skeleton he preserved, which is shown by overlaying the field photo on a modern image of our skeleton for an exact match.

The published version of the field photo is labeled JNG/361, which stands for Jemdet Nasr Grave number 361. Jemdet Nasr is the name of a site that lends its name to a particular time period, but there is much debate today about its temporal extent. In fact, the majority of Woolley’s late JN graves are most likely Early Dynastic I period and the earlier are most likely Uruk period.

Field photograph of the Uruk skeleton before waxing

Field photograph of the Uruk skeleton before waxing

The original field photo is labeled PG1834. This number comes at the tail end of the sequence of assigned PG numbers (which end at 1850) and in fact Woolley renumbered many of the series from PG1818-1846 into JNGs because he had gone deeper than the main burials in the Royal Cemetery or believed the burials to be earlier.

Sorting out these re-numberings is a big challenge but one that’s vital to understanding the sequence of burials and the progression of the dig. As Woolley went deeper in the Royal Cemetery area (PG), he decided to uncover the earliest levels of the city and thus he continued to dig down from the base of some of the PG graves. These areas then became test pits and he made a good number of them over the latter years from 1929-1933. Pits A through E were located in the Royal Cemetery area, but Pit F was located north of there (and it was the findspot of the extended Ubaid period skeleton).

Woolley closed excavations in Pit F in January of 1930 and by that time he had already decided to dig even deeper in the Royal Cemetery in order to compare to the results of Pit F. To do this, he jumped ahead in his lettering scheme and created pits Y and Z in an area of many of the PG1800 graves.

In Pit Y he found a few graves of the flexed type, including JNG/361. He used the same technique of pouring wax on the body that he had with PFG/Z (Pit F, Grave Z, the Ubaid period skeleton 31-17-404). Our biggest problem, however, comes from conflicting data he recorded. In his chart of burials he tells us that the body in JNG/361 was lying on its right side. The skeleton we have, which matches the position and condition of the field photo skeleton, is lying on its left side. Either Woolley mistakenly wrote right when he meant left, or he mis-wrote the number of the JNG grave. For example, JNG/351 is said to be lying on its left side. Whatever happened, there is clearly a mistake somewhere. Verifying the exact mistake is almost impossible. It seems most likely that this really is JNG/361 since the photo is labeled as such. Woolley probably noted that the body was facing to the right as we look at it and wrote it down as on its right side.

Associated with the burial of JNG/361 were four pottery types. Two of them are not overly diagnostic, but the other two are rather clearly late Uruk types, which gives us a date around 3300BCE. It is a very rough date that could be off by as much as 200 years either side, but it shows us that this body is at least 1000 years later than the Ubaid one, which we have roughly dated to 4500BCE.

Burial practices are typically quite tenacious, unchanging for long periods of time because they are usually centered in deeply held beliefs. At some point in the 1000 year interval here, the method of burial as reflected in position of the body changed. In fact, most burials at Ur are flexed and on their side, like this one, but the very earliest burials of the Ubaid period were not. In the old days of scholarship, such a change would typically be used to suggest an influx of new people, an overthrow of a current population by some other. This is not necessarily the case, however. There may have been some outside influence, but that does not mean an invasion or overthrow.

In fact, both the Ubaid and Uruk cultures were rather far-reaching. Characteristics of the Ubaid culture are found throughout much of Mesopotamia and Uruk even more so. The Uruk in general is thought of as the proto-state period, when state government was arising and managing increasing numbers of people. This is the time when Ur and many other places were becoming what we today would consider true cities. Yet both Ubaid and Uruk peoples relied on far-reaching trade networks to bring in much needed materials. Along with these almost certainly came new ideas.

The shift in Ur between the times of these two burials is a fascinating one and we hope that the remains of the two individuals can give us more insight into that change. The Uruk period skeleton in particular is the focus of a current class in the Living World in Archaeological Science, where Penn undergrads and grads are working with Penn scientists to reveal more on its physiological condition and cultural significance. Thus far, x-rays have shown a good deal but it remains difficult even to determine the gender due to the positioning of the body and the wax and soil covering. The students are discussing these difficulties and trying to determine ways to investigate the body in spite of them. They are also learning about just what kind of information we might be able to obtain and the various scientific techniques that could result in much more. Read more about it in this article at the Philadelphia Inquirer.

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Films of Sitio Conte as a primary source material

The Beneath the Surface exhibit has positioned the film records of the expedition to Sitio Conte prominently within the exhibit. We asked Clark Erickson, the lead curator of the exhibit, what the films mean to him as primary source materials in the history of archaeology, and especially of this site.

The video advances my agenda of “peopling the past” and “visualizing the past” for the exhibit and is an incredible archival testament about the practice of archaeology in 1940. Over the weekend, I spend an hour watching the loop over and over with the grandson and granddaughter of J. Alden Mason and the son and daughter of John Jr. who was on the dig as a high school student. They were excited and nearly drawn to tears seeing their ancestors in the film doing their archaeological work. *

Penn student Monica Fenton is writing her Senior Honors Thesis on Sitio Conte (she was one of the student curators for BTS). We noticed that the film records important contextual information that is not documented in the formal still photography of the excavation team. We hope to capture stills from all the film of pans over the archaeological objects in situ to help relocate and establish associations with individual bodies in Burial 11 and other burials at the site.

It is often a source of wonder that recordings such as these, casually taken in their day, can become significant to later researchers. What are we creating today that will have resonance to future researchers?

Other Sitio Conte film footage may be seen here:

*Mr. Mason sent us the following note this week “Being in that exhibit, seeing the items and the inspired three tiered display of the burial ground … I felt like I was completing the circle. Finally, all those stories and my grandfather and father’s roles in it came to life. You can’t imagine what a shock and joy it was to see the film footage (some in color – new to the time) of grandfather, circling around the dig, pipe in mouth, carrying equipment, bending down to take a closer look at the progress, picking away at the earth with his trowel, looking pensive, interacting with the team, and getting on with the job. How amazing to look at pictures, burial ground maps, the working tools, the trip medicine chest, expedition journals and his portable typewriter (portable!?! funny to see this clunky machine in comparison to smart phones and what we use and have available today). Moreover I was astonished by the film scenes of my father, as a lanky, floppy blond haired 17 year old, busily moving and organizing sacks of field work. This was a young man I recognized but did not know until that moment. To be followed by a new perspective and much clearer mental picture and understanding of what all those stories meant and now even looked like. Magical!”

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Yassıhöyük Village: Where and when did the villagers come from?


Vew of the Sakarya river that flows west of ancient Gordion, and continues to give life to the villagers

About 100 years ago the earliest known inhabitants of the Yassıhöyük village arrived there from different regions of Anatolia, and settled near the banks of the Sakarya river that flowed through the ancient settlement of Gordion.


Iron tipped wooden plough used until 1960s for manual agriculture

The early subsistence base was animal husbandry supplemented by farming cereals with horse and iron-tipped wooden plough, a threshing board with flint, pulled by oxen, to separate grain from straw (as known from the Neolithic era), on an average of one hectare of land (2.5 acres). This simple technology lasted until 1950s.


Herds taken through harvested fields in early morning

Starting in 1920s the the early settlers moved away from the river, to higher ground toward the ancient settlement, to escape the malaria epidemic. They were joined by immigrants, as far away as Romania, Bulgaria and Bosnia, who were settled in the region.

In time, itinerant shepherds from the mountainous northern region of the Bolu province migrated in winter months to graze their sheep and goats on the wide open steppeland.


shepherd with felt coat


Several varieties of Angora goats


Several varieties of Angora goats


Several varieties of Angora goats


Herds taken through harvested fields in early morning

With abundant rain and snow, the vast open land provided grazing for large herds, among them the Angora goat (tiftik keçisi), that was favored for its milk and its mohair wool.

The itinerant shepherds spent 6 months with their large, not-so-friendly-to-strangers sheep dogs of Kangal breed that wear iron spiked collars to protect the flock from wolf packs.


Sheep dogs for a large flock

Up until 70 years ago the sheep and goat population was 250,000 in YH and in the region of eastern Sakarya river valley. An important product of the animals was the dung cakes used for fuel. A major decline in caprine population the last 15 years was reversed, due to government subsidies extended to shepherds to encourage production of milk and wool.


Cow dung cakes drying in the sun for use as fuel


After drying, it is piled up in a shed in courtyard

Today, many of the “itinerant” shepherds have become landed farmers, practicing mixed agriculture and animal husbandry. Those who are not landowners keep exclusively sheep and goats.


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Sitio Conte in Real Time: February 7, 1940

Wed. Feb. 7. Ash Wednesday. In spite of “Carnival” yesterday, all men at work by 7:10. Much [?] at this hour, calm & not hot. Got very hot during day. Lothrop had chicha party for men after work. Cook is apparently dissatisfied & threatens to leave frequently. Muse have good talk with him & settle things. Did a little cataloging at night.

-J. Alden Mason, Diary, February 7, 1940


It was back to work for the team after their Carnival (or what we call Mardi Gras) celebrations the day before.  It seems even though it was Ash Wednesday, the party didn’t stop. It was a tradition for the visiting excavation teams to throw a “chicha” party at least once for the men during their stay.  The Lothrops were leaving soon for good and perhaps this was their good-bye party.

Speaking of parties! Let’s take a break from the daily grind of the Panamanian Expedition and jump ahead in time several months and then years.

When Mason returned from Panama to the Museum in April of 1940, they came back with crates and crates of gold adornments and plaques embossed with animal-human motifs, pottery, tools, and weapons.  The objects were quickly accessioned and put on display by June, 1940.  We don’t have many records or any photographs from the first installation of the Sitio Conte collection, but we do have an eye-popping newspaper clipping from June 16th.  In it, Chiquita Beck of Philadelphia poses with many of the gold ornaments on an alter in the Mesoamerican Gallery. What a different time this was in the Museum!


That was 75 years ago. Today, February 7, 2015, marks the opening of a new exhibition at the Penn Museum, Beneath the Surface: Life, Death, and Gold in Ancient PanamaWhile you can no longer recline on our treasured objects or wear the priceless gold adornments of the Coclé chiefs, you can learn more about this mysterious and complex society.  Come explore the rich culture of the Coclé people. On exhibition are large golden plaques and pendants with animal-human motifs, precious and semi-precious stone, ivory, and animal bone ornaments, and detail-rich painted ceramics. Beneath the Surface runs from February 7, 2015 to November 1 , 2015.

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Sitio Conte in Real Time: February 5, 1940

Mon. Feb 5. Warm, happy, rather clear. 9 diggers & foreman. Lothrop & I troweled on large area of broken pottery & [?] in w[est]. end of trench. Merrill surveying. Photo’d skeleton & cache in Tr I & [?] took up broken broken pottery. Corning washing & selecting sherds. John [?] [?] rolls of canvas on main house. Found first small gold plaque which Corning treated with gum arabic. Many men with hangover, tomorrow is Carnival. Victor left at 11, making 8 men plus Eulogio.

-J. Alden Mason, Field Notes, Feb. 5, 1940

Mon. Feb 5. Warm, happy, rather clear. 9 diggers & foreman. Lothrop & I troweled on large area of broken pottery & [?] in w[est]. end of trench. Merrill surveying. Photo'd skeleton & cache in Tr I & [?] tool up broken broken pottery. Corning washing & selecting sherds. John [?] [?] rolls of canvas on main house. Found first small gold plaque which Corning treated with gum arabic. Many men with hangover, tomorrow is Carnival. Victor left at 11, making 8 men plus Eulogio.

Some of Mason’s writing is difficult to read. Words unable to be deciphered are marked with [?] in the transcription above.

Mason’s daily journal entry generally describes the weather, who worked on what, and the day’s main activities. On a typical day, they worked from 7 am to 4 pm with an hour break for lunch at noon.

The “9 diggers & foreman” were from the local area. They received $1.00 a day, the foreman $1.25. In later writings, Mason described them as such: “Most of men belong to one family, Ramos. 4 brothers & many other relatives. Clannish, but don’t fight with outsiders, that is with workmen from other fincas.” The foreman at this early point was Eulogio Ramos, eldest of the brothers and “more or less the patriarch of the region.” Sam Lothrop told Mason that Eulogio was a “‘witch’ (brujo), [and] that everyman on the job would quit if he gave the order, etc., and that he must be employed as foreman or favored person at higher salary.”  Mason did employ him as the foreman until he began to doubt his “authority and influence” later on and let him go with no trouble. The worker, Victor, who “left at 11″ worked mainly on running errands because he had a horse and lived the closest.

Merrill’s field notes for Feb. 5, 1940.

Includes surveys of both Trench I and Trench II.  The photographs from each page are included below.


Fig. 1. Looking W. Feb. 5, 1940 Trench 2
General View
Photo C-5


Fig. 2 Trench 1
Two skeletons
Burial or Grave 3


Fig. 3. Same (as Fig. 2) with grid but not vertically down


Fig. 4. General View Feb. 5, 1940
Trench 1 looking N

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Sitio Conte in Real Time: February 4, 1940

Sun. Feb. 4. Pleasant quiet warm day, first quiet day in ten days. Most of us up a half hour late. Merrill spent whole day on his drawings. Lothrops took a little trip up river to see Verrills site and found two new ones. The Cornings spent most of day straightening up equipment. John M. took things easy. I spent morning housecleaning my tent and distributing general equipment I had in there, and in afternoon until 5:00 went over paper accounts and got everything filed and in order. Talked over maps[?] with Merrill & began a letter in evening.

-J. Alden Mason, Field Notes, February 4, 1940


Sunday, Feb. 4 was a day of rest for the excavation team. Now that the initial work of setting up camp is over, we get a glimpse of what camp life is like during their downtime.

Someone we haven’t heard much about this whole time is John M., Mason’s son, who tagged along for the whole of the expedition.  John Jr., was a senior at Tredyffrin-Easttown High in Berwyn in 1940, but had taken the school year off to join the expedition as a “general helper.”  Below is a photograph of John Jr., taking things easy indeed!mason_jr

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Sitio Conte in Real Time: February 3, 1940


-Robert Merrill, Field Notes, pg. 1, February 3, 1940


View Page 1 from Merrill’s field notes.

Today marks Robert Merrill’s first day on the job at Sitio Conte.  His meticulous field notebook contains–in exquisite detail–his notes, drawings, and photographs of the excavations. It is an invaluable tool for learning about the Cocle people and the burials at Sitio Conte.

A retired civil engineer, Merrill worked with Mason in Mexico in 1936, and was back as the surveyor, draftsperson, and photographer for this expedition.

Merrill developed a system to record the fieldwork by using a graduated string grid (see Fig. 3) to accurately plot, number, and catalogue all the uncovered objects. This innovative approach allowed, as Mason later put it, “that we [can] replace almost every specimen in its original position, depth and associations.”  Merrill’s square grid enabled him to photograph groups of artifacts in situ from above and to precisely plot them on graph paper. The whole contraption can be seen in Fig. 4.

Today, thanks to Merrill’s documentation, the exhibition staff and curators of Beneath the Surface: Life, Death, and Gold in Ancient Panama were able to recreate the famous Burial 11 with many of the objects mounted and oriented as they were found by Mason and his team.


Fig. 3


Fig. 4


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Ur Project: January 2015

Pseudomorphs on Metal Objects from Ur
A closer look at U.14097 and U.9134 (Penn Museum Nr. 31-17-241 and B17476)
Chisels from PG 1653 and PG 537


This month’s Blog entry is written by researcher Kyra Kaercher with technical assistance from conservator Tessa De Alarcon. Special thanks to the Conservation Department for the macro photo details of the objects.


As the Kevorkian Fund Research Assistant working on the Ur Digitization Project, I work with the objects from the excavations and try to match them to Woolley’s records. The past few months I have been focused on the metal tools and weapons, specifically the copper alloys (copper and bronze). When I first started on this project, I noticed the copper alloys fell into two distinct categories. One was reddish-brown, metallic, and had pitting on the surface. The other was blue-green with different textures on the surface. After talking to our conservator, Tessa De Alarcon, I learned the reddish-brown pitted metals are probably caused by an electrolytic reduction treatment of the copper alloys, and the blue-green metals have not been treated with this treatment. I have looked at about 45% of the metals from Ur that are located at the Pennsylvania Museum, and 48% of them were probably electrolytically reduced.

Electrolytically reduced on left and not electrolytically reduced on right.

Electrolytically reduced on left (B16432) and not electrolytically reduced on right (B17476).

Electrolytic reduction treatment was used in order to protect the copper alloys from corrosion. The treatment uses an electric current run through a ionic solution. This method removes the cuprite, or corrosion caused between the copper alloy and the soil minerals. Sometimes a thin layer of new metal is laid on the surface of the object if the solution is not changed regularly. This makes it hard for more chemical analysis to occur, especially surface analysis such as XRF.

Of the remaining 52% of copper alloy objects examined, 33% have pseudomorphs. Pseudomorphs are a mineral compound that appears in an atypical form. Common pseudomorphs are petrified wood and fossils. In metals, pseudomorphs appear where metal has replaced the organic material that is either part of the object, or that the object was lying on when buried. The pseudomorph retains the appearance and dimensions of the original material. The most common pseudomorphs on the metals from Ur are wood, leather, rope, textiles and basketry. The mineralization of the material sometimes contains enough detail to specify the genus and species of the organic.

The two objects I looked at more in-depth were U.14097 (31-17-241) and U.9134 (B17476). These objects are both chisels found in personal graves. U.14097 was found in PG 1653. It is the only object from this grave, and Woolley publishes neither the object nor the grave. U.9134 is one of several objects from PG 537. This grave included spearheads, daggers, a mace, and a saw. Woolley dated this grave to the Early Dynastic III Period (roughly 2600 – 2400 BCE).

Fiber pseudomorphs on U.14097 (31-17-241).

Fiber pseudomorphs on U.14097 (31-17-241).

The fiber pseudomorphs that appear on the chisel from PG 1653 can tell us much about the way rope was manufactured and used at Ur. These pseudomorphs are an example of positive replacement where corrosion products replace the fiber as it decays, forming a positive fiber cast. The close-up view shows us a small string that is braided. Most natural fibers are spun as either an S-spin which is to the right, or a Z-weft which is to the left. This fiber is an S-spin in the single threads that combine to form a three string braid. This object was probably laid on or in a coil of the fiber because it is in a random pattern around one end of the chisel. If the fiber was attaching something to the chisel, or wrapped around one end, a pattern would appear. The preservation of the pseudomorphs is to such a degree that the fiber can be further analyzed, and researchers might be able to identify the species of the fiber.

Textile Pseudomorphs U.14097 (31-17-241) on left, U.9134 (B17476) on right.

Textile Pseudomorphs U.14097 (31-17-241) on left, U.9134 (B17476) on right.

Above are two examples of textile pseudomorphs from the copper chisels. On the left is an example of positive replacement, and on the right is an example of negative replacement. The positive replacement creates a cast of the textile, whereas the negative replacement creates an impression of the textile. In U.14097, the textile is woven, as one can see the individual strands are interwoven with each other. In a better sample, the pseudomorphs may point to a difference between wool and plant fiber (like linen) material. In U.9134, the textile left a very strong vertical impression, and there is some horizontal impressions as well, pointing to a woven textile. These textiles point to the chisels being laid on or near the body probably in association with clothing or they were possibly wrapped in some sort of cloth. The portions with pseudomorphs are not large enough to get a pattern to see if the wrapping was intentional or not.


Basketry/Matting Pseudomorphs on U.14097 (31-17-241).


Above is an example from U.14097 which includes pseudomorphs of basketry or matting. In comparing this specimen with the textiles, we can see that both are woven. However, this is made from a thicker material like reeds rather than fiber. The thicker material points to a plant fiber, which is found in basketry or matting. With the help of a specialist, this plant fiber might be identified down to the species.

Leica Picture

Wood Pseudomorphs on U.9134 (B17476).


Wood pseudomorphs like those found on U.9134 can be determined by the pattern they leave on the metals. The wood pseudomorphs replicate the cell walls of the wood, leaving an exact copy of the structure. The wood species can be identified based on this replica, and changes to the wood and the soil around the wood can also be detected. Like the fiber, textiles, and basketry, it looks as if the chisels were laid on the wood, rather than being embedded in the wood. On objects such as the axes, wood pseudomorphs appear in the sockets, showing the objects were buried hafted to a wooden handle.

One object may have multiple types of pseudomorphs, showing how the object is made or used. The two chisels shown above were laid on different organics that were then preserved on the chisel itself. Pseudomorphs are useful in that they show organics, that have deteriorated, to such a degree they can be identified down to the species level. This gives us the opportunity to learn much more about the use of these objects, as well as the material used to create these objects. Our website, www.ur-online.org, is up and running, but is still a work in progress. It contains many more images of these objects as well as the other objects in PG 537.

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Sitio Conte in Real Time: February 2, 1940

Came down on a cache of a half dozen apparently complete vessels this afternoon which will be photo’d and taken out tomorrow. A few gold beads found by the workmen in the soil. Also today began to uncover a great mass of broken pottery.

-J. Alden Mason to Horace Jayne, February 2, 1940

In his first letter to the Museum since arriving in Panama eight days earlier, Mason wrote to Director Horace Jayne about their progress thus far. He briefly described their campsite (“everything is perfectly lovely to date”), initial excavation finds (“have found plenty of sherds so far”), and his dwindling budget (“naturally everything has cost about twice as much as the budget allowed”). Even though they suffered insect bites, the team was fairing well, as the “old camp cook who is a find…makes cake, pie, cinnamon buns, etc.,”!

Anticipating the arrival of Robert H. Merrill, surveyor, engineer, and photographer for the expedition and John B. Corning, a research associate in the Museum, as well as Corning’s wife, Julia, to the site, Mason included a post script stating that all had arrived “tired & hungry” that evening.  Now that the whole team was in place, the full scale excavations could begin!

It only took a matter of days for the local workmen, numbering between 20 and 30 each day, to clear out and construct the base camp for the excavation team. Over the course of the 8 days, they’d built a pier and steps to the river, dug three latrines, began construction on two camp houses, three tents, a kitchen, a shelter for the laundress, and a storehouse.

In his description of the sherds and skeletons found so far, Mason wrote that: “today [they] began to uncover a great mass of broken pottery. If you don’t remember the set-up they apparently threw vessels into graves and the fragments scattered over a wide area, and then they walked on them. So hundreds of sherds must be brought home, sorted and the vessels repaired.”

But with thousands of sherds being uncovered, how would Merrill, the surveyor and photographer, be able to accurately record and document all of them for later research?



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Blue lines: multispectral imaging for pigment identification

Visible-induced infrared (IR) luminescence is the invisible light that some materials produce when they are excited with visible light. We can capture that invisible light with a modified camera and use it to identify those materials and find out where they are. For those of you who follow the Artifact Lab Blog, this technique will sound familiar. Molly Gleeson used it to identify Egyptian blue on a shabti box that she was working on. Guess what? The technique can be used to see other materials too! In examining a 12th-century Islamic manuscript, NEP27, I needed to find a way to distinguish between indigo and ultramarine. Both are blue in visible light. Both are made with elements that are below the detection limits on our pXRF, our usual go-to method for elemental analysis.

Detail of marginal elements on page 360 of NEP-27. Notice the blue outlines around the gilded designs.

Detail of marginal elements on page 360 of NEP-27. Notice the blue outlines around the gilded designs.

It was starting to look as if I’d need to take a sample to examine with our polarized light microscope and possibly send out for x-ray diffraction, when my colleague, Tessa de Alarcon, remembered a single sentence in an article on Egyptian blue and Han blue, the same reference that Molly used for her work. What did it say? “The emission of indigo is reported to be at c. 750 nm while that of lazurite at c. 830 nm.” (Verri, 1012) There it was in black and white. The secret to a non-destructive method for answering the question of indigo or ultramarine. Those numbers are the wavelengths of light that they produce when excited. Both are in the infrared range and invisible to our naked eye, but we can see them with our camera. Lazurite is the color component of ultramarine, so if it has emissions that are different from indigo, maybe we could use filters to separate them.

To find out if this would work, I found a couple of dry pigment samples, mixed them up with gum Arabic, and painted them out on a swatch of paper. With this set of knowns, I set up the Mini-CrimeScope, our tunable light source, and the modified camera to try different light and filter combinations. It turned out that while both indigo and ultramarine luminesced with exposure to light centered around 455 nm, I could eliminate the indigo with a filter cutting off at 830 nm. Using this set up, I tried it out on the manuscript, and sure enough, the blue decorative elements fluoresced just like the natural ultramarine sample.

Detail of page 360 illuminated with 455nm light captured in infra-red, grey scale. The blue lines seem to disappear and are hard to distinguish from the paper. They didn’t disappear though; they’re fluorescing!

Detail of page 360 illuminated with 455nm light captured in infra-red, grey scale. The blue lines seem to disappear and are hard to distinguish from the paper. They didn’t disappear though; they’re fluorescing!

The false color image helps to visualize which areas are luminescent. In the photo, the information from the IR photo replaces the red channel, so the red lines around the decorations are the luminescent parts . Or in this case, the ultramarine!

Detail photographs of page 360 illuminated with visible light and with 455nm light captured in infra-red combined into a false color image. The blue lines now appear red, helping to show where the luminescence took place.

Detail photographs of page 360 illuminated with visible light and with 455nm light captured in infra-red combined into a false color image. The blue lines now appear red, helping to show where the luminescence took place.

This wasn’t true across the board, but the blue decorations don’t look the same throughout either. I’m not sure if this means that ultramarine was used in some areas, but not others, or if different sources of the pigment have enough variation to produce different results. My samples included different sources for the ultramarine, which were also variable with their luminescence, so I’m thinking that the luminescent component might be variable depending from batch to batch. I’m still working on the details to see if we can use this as a diagnostic technique, but this is a promising development!

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