How do we describe a work of art: color, line, and texture? How about Neutron Activation Analysis (NAA)?

Neutron Activation Analysis

NAA has helped track copper archeological finds to specific copper mines. Go to the Art Attack page of the WhyFiles to read about this detective work. Richard J. Cashwell explains NAA at the Web site of the University of Wisconsin Nuclear Reactor of the University of Wisconsin-Madison College of Engineering.

NAA is based on the detection and measurement of characteristic gamma rays emitted from radioactive isotopes produced in the sample upon irradiation with neutrons. This emitted radiation is a 'fingerprint' of the element, and a report is issued giving elemental concentrations in the unknown sample. Once the exact proportions of important trace elements are known, samples can be compared to existing ones, and to each other. Because copper from different mines contains different combinations of trace elements, NAA allows the tracing of archeological artifacts to specific copper mines. Look at the animation of the NAA process, and the image below.

Back at the Art Attack page of the WhyFiles site we find eight high-tech ways to do research about art. Let's consider carbon dating.

Carbon Dating

The Cave of Chauvet-Pont-D'Arc was discovered in France in 1994. Go to the Web site to see the beautiful artwork from ancient times. Accelerator Mass Spectrometry (AMS) was used to date the charcoal from the cave drawings around 30,000 years before present: learn how by following the Time and Space link from the home page, and then select Dating.

A clear explanation of how a radiocarbon age is measured using radiometric counting and accelerator mass spectrometry (AMS) can be found at the Rafter Radiocarbon Laboratory Institute of Geological and Nuclear Sciences page.

Accelerator mass spectrometry (AMS) does not rely on radioactive decay to detect the ¹⁴C but instead counts the ¹⁴C atoms in the samples as well as ¹³C and ¹²C. The small samples required for AMS mean that it is possible to remove a sample for dating without significantly damaging the object.

X-ray Fluorescence

Let's look at another method of elemental analysis used by museums: X-ray fluorescence. There are distinct advantages of X-ray fluorescence: it can operate outside a reactor and it is non-destructive. X-ray fluorescence has been used to detect forgeries, for instance, "antique" silver and "Old Masters" paintings.

But concern about forgery is not the only reason to investigate a work of art. WhyFiles also tells the story of "The Feast of the Gods", a 16th century masterpiece painted by Bellini, modified by Dossi, and finally repainted by Titian. See the resulting X-radiograph as well as the painting as it looks now at the National Gallery of Art in Washington, DC. Another wonderful, inclusive site is WebExhibits where great details are given about the investigation of this painting.

Go to the Harvard University Art Museums site for more about analyzing paintings with instrumental analysis.

Polarized Light Microscopy

Return to the WhyFiles and this time consider polarized light microscopy for pigment analysis. Here Walter McCrone reminds us that "analytical techniques cannot prove that somebody actually painted a work of art. They can, however, rule out that possibility, by proving that the materials used were unavailable when it was supposedly painted." Go to this Web site of the McCrone Research Institute to read of the Institute's investigation of the Shroud of Turin.

More about polarizing light microscopy can be found here. Janet L. Schrenk and John L. Bordley developed this course,Chemistry and Art, at The University of the South with NSF support. The practice pages where you can test yourself on pigment identification are really wonderful. Did I mention that there were movies here also?

Web Sites Devoted to the Arts

Go back to the WebExhibits Creative Arts page for a select group of reviewed sites devoted to the arts. Go to WebExhibits: Pigments through the Ages. Let's try Egyptian Blue. Here you can learn about the history of the pigment, how to make it, and its chemical composition.

From West Jessamine High School in Kentucky comes a great site on pigments called The Chemical Artist. Start with the color Red. Learn that vermillion is a red that was produced from cinnabar, an ore of mercury--and lots more. Go to the Arts Foundation of Michigan to see step-by-step photographs of how to make a fresco.

A fine summary site on Science and Art is found at the Indianapolis Museum of Art. Learn about paints, painting techniques, and how scientific processes have affected artists' techniques.

A site with a good history of paints is Gamblin Artists Colors. The Smithsonian Institution selected Gamblin to recreate formulas for oil colors commonly available to painters of the 18th and 19th centuries. This site compares the paints available to the Old Masters and modern artists and discusses the impact of these paints on the techniques used by artists.

Finally, we all need to take care of our treasures. The American Institute for Conservation of Historic and Artistic Works has a site devoted to the restoration, preservation, and care of treasures. Further information about restoration and preservation can be found at many museum Web sites.