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A Note from
the Director
Equipped with his five senses, man explores the universe around him and calls the adventure Science.
--
Edwin Powell Hubble
This month's eNews is all about the adventure of Science, with a capital "S"!
In this picture the woman exploring the universe is Dr. Karen Steelman. She's using a blow torch to seal a container holding a radiocarbon sample. Karen runs one of only two laboratories in the world that can prepare rock art samples for radiocarbon dating using a method called plasma oxidation. She is currently a Full Professor at the University of Central Arkansas.
Guess what! Karen is bringing her incredible expertise to Shumla! That's right! She will be formally joining the Shumla team of scientists as Assistant Research Director in January. We could not be happier to have such a respected scholar and such a good friend join our team.
Karen will find herself in good company at Shumla. I don't mean to brag, but at Shumla we do awesome science everyday in the name of systematically exploring our small but important corner of the universe. Read on to learn about
some of Shumla's adventures in Science with a capital "S".
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The Art of the Science of Art
"I have learned that what I have not drawn,
I have never really seen."
-- Frederick Franck, The Zen of Seeing
Shumla puts these words into action. When we carefully illustrate a rock art figure, we can truly "see" that figure. As a result, figure illustration is an essential step in our recording process. Over time we've refined our methods, employing new state-of-the-art technologies. Shumla's illustrations have grown into something much more than "just a drawing."
Introducing... the graphic database!
Shumla's graphic database is a "living" document. It contains a structured set of all the graphic and spatial data for a single figure. These documents are digitally accessible and can be easily replicated, verified, and updated.
To produce graphic databases, Shumla uses the WACOM Cintiq Interactive Pen Display and Adobe Photoshop.
If you have a sweet tooth, think of the graphic database as a multi-layered cake. Each layer of the graphic database is packed full of meaningful and informative data about different aspects of a single rock art figure. These layers build upon one another, producing a detailed record for each figure in a panel.
The foundation of the graphic database is the color-managed, close-up figure photo, plus any Dstretch enhancements. These enhancements help us see faint aspects of the figure invisible to the naked eye.
Next comes the illustration. The full-color illustration in Photoshop contains separate layers: 1) a Sketch layer, 2) Associated Figures layer, and 3+) all the separate color layers of that figure.
Next, in another layer, we record the different wall conditions affecting the figure. For example, we create separate layers for spalled areas of the figure, shown in white, and obscured parts of the figure, shown in gray.
Then, we include a series of analysis layers for chemical and microscopic data. We incorporate all the analysis locations and data collected. In the photo below, you can see where Shumla collected microphotos to determine the stratigraphy of red and black paint within this figure. We also insert the microphoto itself and the lab results into the layer for quick reference.
The final layer is detailed notes recorded by the illustrator, noting new figure attributes, observations, and questions for later reviewers and field checks.
Shumla's graphic database is truly a "living" document. It provides a digital, layered history of all the documentation completed for a single figure. It's important to note that these graphic databases are never fully "complete." We are always building upon our analyses, refining the illustrations, and adding updated notes. And that is the layered, multi-dimensional art of the science of studying art.
Guest contributor, Audrey Lindsay, was a former Shumla intern during two summer terms and is currently contracting with Shumla to build graphic databases. Thank you, Audrey!
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Exposé!
Shumla's New Assistant Research Director Tells All!
All about her science, that is...
Jessica Lee: Hi Karen! Let's jump right into the nitty gritty. Tell us about your Science.
Karen Steelman: My main research focus is radiocarbon dating rock paintings and using chemical analysis to identify pigments used by ancient artists. For years I have been using chemistry and the scientific method to assist Shumla archaeologists in their mission to document and study the rock art of the Lower Pecos. I'm excited to do it officially as a Shumla employee when I start in 2017!
JL: Give us an example of how you've used chemistry in the Lower Pecos.
KS: At Eagle Cave, near Langtry, the mural is dominated by an figure that is over 5 ft. tall with other nearby paintings. We used two independent methods to provide reliable ages for three of the Pecos River Style paintings. The first method called plasma oxidation dated the organic elements in the paint. The second method dated the minerals that are found below the paint and that are deposited on top of the paint over time giving us minimum and maximum age for the painting event.
JL: You have two ways to date the same paint, meaning you can be doubly sure of the result if the date from the two methods match?
KS: Exactly!
JL: So...we're on the edge of our seats. What was the date?
KS: Our results show that the art at Eagle Cave was painted between 1740 and 1420 BC. That's over 3,000 years ago!
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Eagle Cave 5 ft. tall figure dated to over 3,000 years old.
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JL: That's amazing. Can you give us the "easy" summary of the scientific methods you use?
KS: Absolutely. I'll start with
Portable X-ray Fluorescence (pXRF).
pXRF is non-destructive. It is an instrument we hold up to the paint to determine the minerals used to mix the paint. For example, manganese for black and iron minerals for red.
Fourier Transform Infrared Spectroscopy (FTIR) is a method we use after a sample of paint has been collected and brought back to the lab. FTIR involves
shining infrared light on the paint to identify its mineral make-up.
X-ray Diffraction (XRD)
is a technique where we
watch how X-rays scatter or diffract off of a crystal, we can determine the interatomic distances (how far atoms are apart) and their arrangement in the crystal. (This is the same method used to determine the structure of DNA!) These distances and atom arrangements are unique to specific minerals, so we can use it for identification.
Plasma Oxidation
is how we prepare tiny rock art paint samples for dating. We have to separate the organic material in the paint (which can be dated to when the paint was mixed) from the minerals (which would give a very old date when the rock was formed millions of years ago). W
e use a radio frequency generator to create an oxygen plasma or glow discharge. The electrically excited oxygen reacts with organic material in paint samples to form carbon dioxide and water, but leaves minerals intact as solids. We collect the carbon dioxide and then convert it to graphite which can be radiocarbon dated.
Accelerator Mass Spectrometry (AMS)
is how we r
adiocarbon date tiny rock art paint samples. A special mass spectrometer with a particle accelerator is used to count the number of carbon-14 and carbon-13 atoms to determine the age.
JL: Wow! That is incredible. Shumla is very lucky to be adding such a decorated scholar to our staff and amazing scientific methods to our in-house process. Thank you for speaking with me today!
KS: You're welcome! I'm really looking forward to moving to Comstock and becoming an official part of the team.
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Spotlight on Shumla Interns!
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Our summer interns are proving their mettle against bees, 100 temps and advanced technology.
We love our new interns,
Ashley Busby, Victor Beckmann and
Megan Vallejo. They are fast learners, hard workers and making amazing progress toward their goals. They proved themselves
in the field - fighting off swarms of bees and beating the heat. And they've proved themselves in the lab - grasping the complexity of Shumla graphic databasing and creating fantastic figure illustrations on the Wacom Cintiq pen display. We are so lucky to have them!
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The oldest "books" in
North America are disappearing.
Donate now to help us save this ancient library.
Every dollar you give will be matched $1 for $1.
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Make Us Smile!
And don't forget to make Shumla your charity on
Amazon Smile. We'll receive .05% of every purchase you make at no additional cost to you. You won't feel a thing except great for giving!
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