News from the Conservation Lab — Pretty in Pink

By Caroline Roberts, Conservator

I’ve been spending a lot of quality time in collections storage lately and have noticed something curious: an abundance of pink! Namely, ancient pink pigment. Why is this so interesting? Because the pink most frequently used in the ancient Mediterranean was made of madder root, a plant-based dye that was used to color textiles as well as a pigment on objects.

Like other organic pigments, rose madder is highly light sensitive and prone to fading. The occurrence of rose madder on so many artifacts in the collection surprises me, given what we know about its fugitive nature. Rose madder also has a unique chemical property that causes it to luminesce, or glow, an orange-pink color when exposed to ultraviolet light. A quick look with a UV LED flashlight can help confirm whether or not the pink on an object is madder.

Marble sculpture fragment KM 1931.441 from Seleucia with pink pigment between fingers and inside elbow.

Visible and ultraviolet-induced luminescence (UVL) images of KM 1931.441 showing orange-pink luminescence of rose madder.

Despite its tendency to fade, I am finding pink on everything from terracotta figurines to marble sculpture to limestone grave markers. I’m also finding it in different hues and on different decorative elements, from flesh tones to jewelry to architecture.  It turns out pink is everywhere at the Kelsey, and it is pretty fascinating.

Marble sculpture fragment KM 1931.15 from Seleucia with pink-colored necklace.

Remnants of pink paint on the surface of KM 21107, a limestone funerary stela from Terenouthis.

November News from the Conservation Lab — Stone Survey Discoveries!

By Caroline Roberts, Conservator

 The stone condition survey is well underway, and I am just floored by the richness and variety of the Kelsey’s stone collection. We’ve got limestone that is packed full of shell fossils (fig. 1), alabaster that has weathered in a way that it looks like a sea sponge … and, best of all, so much of the material comes from sites that were excavated by the University of Michigan. If I had to choose the most exciting artifacts I’ve encountered so far, it would be those from Karanis, Seleucia, and Terenouthis. I’m a self-professed ancient color geek, and an incredible number of these objects still have pigment preserved.

Figure 1. Shell fossils visible along the side of KM 29001, a limestone funerary stela from Terenouthis, Egypt, late 2nd–early 4th century CE.

Take the Karanis stone. I’ve seen hefty jar bases that have traces of pigment and ground still in place, and a libation altar decorated with a vivid orange-red pigment (red lead?) barely visible under a thick layer of burial dirt. At least half of the Seleucia sculptures I’ve examined have traces of pink pigment, including one with a highly detailed painted necklace. I’ve spent years studying the Terenouthis funerary stelae, and even these continue to surprise me. I spotted blue-green pigment on a well-preserved stela that I am eager to investigate further (fig. 2).

Figure 2. Limestone funerary stela from Terenouthis, Egypt, late 2nd–early 4th century CE. Traces of green pigment can be seen in the figure’s left hand and on the recliner cushion. KM 21159.

In addition to revealing the extent of surface decoration on the Kelsey’s collection of stone, the survey is also helping me determine which artifacts are in need of treatment or rehousing. It’s amazing to me how much there is to learn from objects in the collection even now, in some cases nearly ninety years after their discovery.

Ugly Object of the Month — April 2019

By Caroline Roberts, Conservator

This month’s Ugly Object post is inspired by, and can be found next door to, the special exhibition Ancient Color. Although not part of the exhibition per se, the object’s proximity to the exhibition has inspired some museum visitors to view it and its fragmented marble brethren in a different light. The case to the right of Ancient Color contains a group of marble fragments that were previously a part of large-scale sculpture, architectural elements, and — in the case of our Ugly Object — a fountain. They are also, at first glance, colorless.

Female hand holding a jug. Marble, Roman period, 1st–3rd century AD. Pozzuoli, Italy. KM 2975.

 

Take a good look at this fragment. What do you see? I see a rather creepy-looking hand (think Thing Addams) perched atop some kind of vessel. Look closer, and you might actually see traces of pigment. This is probably true for the other fragments in the case, as well as the majority of marble sculpture and architecture from the ancient Roman world. When we consider what’s missing, we begin to see these fragments in a new way — as shadows of their erstwhile complete and colorful selves. We’ve been able to verify the presence of pigments on a few marble objects on the collection using multispectral imaging and other analytical techniques (see the Bacchus head on display on the Color exhibition), and there is undoubtedly more evidence of color to discover!

Come see April’s Ugly Object on the second floor of the Kelsey’s Upjohn Exhibit Wing. And while you’re at it, check out Ancient Color, on display through May 26.

Ugly Object of the Month — March 2019

By Suzanne Davis, Curator of Conservation

In last month’s Ugly Object post, we explored some of my feelings about the interior decorating schemes of Roman Egyptians. But while I could not happily collect their colorfully painted god and goddess figurines, I would acquire this month’s Ugly Object in a hot second. For me, this sprang bag only just barely qualifies as something we could legitimately write about in this blog feature, and then only because it is so moth-eaten and frayed.

Sprang bag made from dyed wool. Egypt. 1st–4th century CE. H. 30 cm. KM 11666.

Made with red, green, and cream-colored wool, this bag is truly a special item. It is featured in our current exhibition, Ancient Color, because it’s so colorful. I enjoy the bold color choices, but I’m even more impressed by the many beautifully executed construction details.

In describing non-woven archaeological textiles at the Kelsey, we often use the word “sprang” to refer to looped or twisted yarn construction like we see in this bag. But unlike our “sprang” socks, which were made using a single-needle technique that is similar to knitting, this bag was made using a twisty, warp-only technique that is sort of like braiding and sort of like weaving.

This bag was made by a master sprang craftsperson. The red, green, and cream yarns interact to create complex patterns, but there are also very cool structural details that contribute to a sense of depth and ornament.

Detail of the border of the sprang bag.

At the top of the bag — as I hope you can see in this detail of the top left corner — the yarns are bundled and held in place with twisting at top and bottom to create an openwork effect. The colored yarns are then carefully twisted to create a highly patterned border along the top edge of the bag, before the green and cream yarns begin a pattern of alternating cable-like and chevron designs.

Here is a closer look at how the green and cream yarns are gathered and twisted as one unit to create what I’m calling a cable-like effect, since this is similar in appearance (and structure) to a cable in knitting.

Detail of two “cables” in the sprang bag.

If we sold replicas of this bag in the Kelsey’s gift shop, I’d pick one up today. This bag is both exceptional and exceptionally fragile. It’s very rarely on view, so I encourage you to come see it for yourself now at the Kelsey!

Ugly Object of the Month — February 2019

By Suzanne Davis, Curator of Conservation

Guess what, everyone?! We have a new exhibition going up right now: Ancient Color. Co-curated by my conservation compatriot Carrie Roberts, it features one her favorite Egyptian gods. Yes, you guessed it, HARPOCRATES RETURNS!

If you read this blog series with any regularity you will know that Carrie has a thing for Harpocrates. And it’s not because he’s really, really good-looking. Although when you know a little bit about him, you’d think he would be. Son of Isis (who we all know is gorgeous) and Horus (not bad if you’re into birds), he symbolizes the newborn sun (nice, right?). He also has magical healing and protective powers, exerted especially on behalf of women and children. This all sounds pretty great, and yet if you wanted a figurine of this god for your house (who wouldn’t?), it would look like this:

Painted terracotta figurine of Harpocrates. Egypt, 2nd century CE. Height 21.3 cm. KM 6947.

Yes, obviously this has seen better days. But imagine it with all the paint still on it! It would be very colorful, but would you really want to look at it every day? I know I wouldn’t, but figurines like this were very popular in Roman Egypt.

Carrie likes this figurine because she is crazy for ancient paint. But I’m not going to tell you about the traces of paint on this little guy, because that would spoil your Ancient Color exhibition experience.

I like this figurine for a different reason: it makes me contemplate two different but equally intriguing possibilities. One: that my decorative taste is very different from that of the typical Roman Egyptian. Would I have hated their interior decorating schemes? I feel like I would have, but I like to imagine what they’d have looked like, all the same. Two: that figurines like this — which were mass-produced by pressing clay into molds, firing the figurines, and then slapping on some paint (I have never seen one of these that was carefully painted) — were meaningful regardless of how they looked. The magical powers of this figurine are not dependent on beauty, in other words. Harpocrates can be messily made and slapdashily painted, and still heal your snake bites. He doesn’t have to look good to take care of business.

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Learn more about this figurine by visiting the Kelsey’s new exhibition Ancient Color, here in Ann Arbor beginning February 8, or anytime online.

 

 

 

 

Ugly Object of the Month — August 2018

by Caroline Roberts, Conservator

This month’s Ugly Object takes the cake for being both incredibly interesting and really, really ugly. What exactly is this rather scraggly looking textile fragment? We’re not entirely sure, although its report suggests that it might have once been part of a cap.

Scrap of wool sprang textile, possibly from a cap. 18.5 x 8.5 cm. Roman period. Karanis, Egypt. KM 12797.

This bit of cap — discovered at Karanis, Egypt — was made using a technique called sprang or nålebinding, an ancient precursor to knitting in which loops of yarn are interlinked using a single needle. Are you a yarn enthusiast or experimental archaeologist and want to try the technique for yourself? Check out Suzanne’s 2016 blog post about an ugly sprang sock, which features links to pages detailing how to knit/link your own ancient sock.

There are other cool things about this sprang fragment, one being its color. We suspect it could be an organic red dye, although analysis would be needed to confirm this. Rose madder, a red colorant derived from the processed roots of the madder plant, was used frequently as a pigment in Roman Egypt and might have been used to color our cap frag. Another cool thing is the black overcast stitches that run along one edge. These could very well be part of the cap’s original construction, or perhaps an ancient repair.

This and other less frequently seen Karanis textiles will be on display in the upcoming Kelsey exhibition Ancient Color, opening February 8, which explores the sources, uses, and scientific investigation of color in the Roman world.

Investigating color on a Roman-Egyptian mummy portrait

by Caroline Roberts, Conservator

This week a team from the Detroit Institute of Arts conservation department traveled to the Kelsey to take a closer look at one of our Fayum mummy portraits. The portrait is normally on display in the Dynastic Egypt gallery and is dated to the Roman period of Egypt (79–110 AD). The woman featured in the portrait is clearly of means, as her gold earrings and necklace, colorful gems, and purple robe indicate. We were curious to learn more about the colorants that were used to paint her portrait and to look for painting details that have become harder to see over time.

Christina Bisulca, conservation scientist at the DIA, brought along a portable spectrometer to identify pigments on the painting. She found evidence of pigment mixtures in multiple areas of the portrait, including the flesh tones, the oval gem at the center of the woman’s pendant, and the drapery of the robe. It appears that the various shades of purple in the robe were likely created by mixing and laying blue and red pigments and dyes, for example. Further analysis is needed to verify these results.

Aaron Steele, the DIA conservation department’s imaging specialist, brought along their powerful infrared camera to see if underdrawing might have been used to sketch the sitter before paint was applied. Although underdrawing was not immediately visible, details of curls along the hairline and sectioning of the woman’s hair could be seen in the infrared images. Details of paint application next to the woman’s face are also much more visible in the infrared. I also had the chance to capture ultraviolet images and produce infrared false color images which provide good information on the distribution of certain pigments (including rose madder and Egyptian blue) over the surface.

We look forward to learning more about the Fayum portrait over the next year and to featuring the results in an upcoming Kelsey exhibition about color in the Roman world. Many thanks to our friends at the Detroit Institute of Arts for their support of this project!

KMA 26801

Examining the portrait with an infrared camera

Analyzing the portrait with a FORS spectrometer

Ugly Object of the Month — April 2017

CAROLINE ROBERTS, Conservator, Kelsey Museum of Archaeology

April’s Ugly Object isn’t an object per se. It’s a specimen — a shell — and it was excavated at Karanis during the 1924–25 field season. It’s rather small and unprepossessing. But to me this shell is a thing of beauty. Why? It is a murex shell, and was once the likely carrier of shellfish purple (or Tyrian purple), one of the most valuable dyes in antiquity. Pliny wrote at length of the Roman passion for purple, and described in detail the extraction and processing of the color from a gland found in the throat of the snail. The dye produced a range of purples from magenta to purple-black. One can imagine the vast numbers of snails that would have been needed for a dye vat large enough to color the yards and yards of textile used in the elite fashion industry of Rome. Pliny cites an observation by the 1st-century BC biographer Cornelius Nepos that a pound of dye would have sold for 100 denarii — about half of the annual salary of a professional soldier. This was some seriously valuable stuff.

Murex snail shell KMA 3712, Graeco-Roman Egyptian galleries, Kelsey Museum

Tyrian purple, like many other natural colorants, has now been chemically synthesized. We can buy a shirt or sweater in purple or any other color today at very little expense, which makes it hard to relate to the craze that drove people to seek out the murex snail on Mediterranean beaches. I can’t think of a color today that screams “bling” the way purple did in the ancient Roman world. Can you?

You can spot the murex shell in the Graeco-Roman Egyptian galleries on the first floor of the Kelsey’s Upjohn wing.

References to the text of Pliny the Elder, The Natural History (Historia Naturalis) Book IX, Chapter 63 are from a translation by John Bostock, M.D.  London: George Bell and Sons, Covent Garden. 1890.

Ugly Object of the Month — October 2016

BY CAROLINE ROBERTS, Conservator

It’s October, folks, and that means the season of decorative gourds and dressing up in festive costumes is upon us. This is partly why I chose this ceramic figurine of Harpocrates as October’s Ugly Object.

Ceramic Harpocrates figurine, with intact ground and paint layers. 2nd–3rd century AD. KM 6449.

Who, you might ask, is Harpocrates? He was a deity worshipped in Ptolemaic Egypt, a child version of the sun god Horus. This ceramic figurine bears many of Harpocrates’ signature traits, such as a finger raised to his mouth, the double crown and crescent moon, and a garland. This figurine is also probably one of many identical ceramics produced for mass consumption.  But what’s really cool, to me, is what’s going on the surface: this Harpocrates is seriously decked out in a variety of well-preserved paint colors, which include black, pink, red, yellow, and blue. Equally cool is the likelihood that other ceramics like this one, many of which retain no polychromy at all, were just as colorful.

While documenting the figurine I thought it might be worth doing some technical imaging of the pigments, to get a preliminary idea of what they could be. The longwave ultraviolet luminescence (UVL) image revealed that the pink garland is likely made of rose madder pigment, and the visible-induced infrared luminescence (VIL) image showed traces of Egyptian blue pigment on the structure next to Harpocrates, as well as on his crown. The remaining colors are likely iron-based earth pigments, and the black carbon-based. Other techniques that could help us confirm these results include XRF or FTIR spectroscopies, the first of which (like imaging) is non-invasive.

Left: UVL image showing orange autofluorescence of madder in the garland. Right: VIL image showing luminescent Egyptian blue stripes to the right of the figure, as well as in the crown.

This highly colorful Harpocrates will be on display at the Kelsey starting February 10, 2017, as part of the upcoming special exhibition The Art of Science and Healing: From Antiquity to the Renaissance, curated by Pablo Alvarez.

Analyzing Roman wall paintings

BY CAROLINE ROBERTS, Conservator, Kelsey Museum of Archaeology

When I think about color in antiquity, I like to imagine how colors have weathered, or changed chemically over time, and the ways these changes impact how we see ancient paint surfaces. Ancient paint can be found on terracotta figurines, marble sculpture, and — most visibly — on wall paintings. The Kelsey Museum preserves a number of Roman wall painting fragments, and curator and professor Elaine Gazda has incorporated these artifacts into her history of art classes. One of Professor Gazda’s students, U-M senior D’Arcy Cook, has taken on the challenge of identifying the pigments from a group of these wall painting fragments.

D’Arcy is a chemical engineering major who is interested in archaeological chemistry and conservation science. Her primary research question was whether pigments on the Kelsey wall painting fragments matched what she had learned to expect based on published literature. To answer this question, D’Arcy used analytical techniques available in the Kelsey Conservation Laboratory and across campus. I felt this would be a great opportunity to learn more about artifacts in the Kelsey collection and to provide D’Arcy with experience analyzing ancient materials.

Using a scalpel, I removed milligram-sized samples of paint from the fragments. D’Arcy analyzed the samples using Fourier Transform Infrared Spectroscopy (FTIR), an analytical technique that identifies materials by detecting signals produced by their molecular bonds. Among other results, her analysis confirmed that Egyptian blue is present on one of the fragments — a pigment I also detected with a modified camera, and which we both observed using a polarized light microscope. Egyptian blue pigment was commonly used by the Romans on wall paintings and sculpture.

This project illustrates how technical research works best by incorporating multiple, cross-checking analytical techniques, and depends on scientists, art historians, and conservators to happen. Many thanks D’Arcy, to Elaine and the Kelsey curators, and to the U-M Chemistry department and EMAL laboratory for their help with this research!

Sampling photograph showing plaster and paint layers on a piece of wall plaster.

 

Visible (VIS), infrared reflected (IRR), infrared reflected false color (IRR-FC), and visible-induced infrared luminescence (VIL) images. The white luminescence in the VIL image shows the presence of Egyptian blue.