The Artists:The Chemists: Rebecca CareyAmber Klein Melissa CofferShawn Leary Rick HamiltonRandall Short Patricia Lang Department of Chemistry, Ball State University

What gives rise to color in a molecule ? What sorts of artists’ pigments were used in ancient and medieval times? How can we determine molecular identity? How is the scientific method applied to a real-world problem?

Teleconferences with experts: Dr. Mary Virginia Orna Dr. Beth Price

Other special course activities: Made a modern synthetic pigment, Prussian Blue, and an egg tempera paint Sampling paints from the statue, microscopic examination of paints, collecting spectral data on the samples, and analyzing the spectra Trip to analytical laboratory in Noblesville to perform additional analysis Oral presentation to Peter Blume and Dr. Orna Collaborated on a written report

Why? (1) characterize artist & work (2) to determine if pigments consistent with the date (3) chronology of paint application (4) conservation Chemistry and Art

Circle of Hans Multscher German Typical to be painted

Kreuztragender Christus -Created by Multscher in 1450

Tools Technique Pigments

Sample Collection A team effort!

Sample Locations Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7

individual pigments, layering, texture, optical properties individual pigments, layering, texture, optical properties physical separation according to color sometimes possible physical separation according to color sometimes possible

How?

cm -1

ATR spectroscopy uses the phenomenon of total internal reflection. Molecular Analysis

K Electron energy level L Electron energy level M Electron energy level K α KβKβ eV Elemental Analysis

1b Sample 1B: White layer under blue, Bottom left cloak out side fold. White pigment on back of all samples

Sample Locations Sample 1 Sample 3

Sample 1 Location: Bottom left of cloak, outside of fold Description: Blue Sample 3 Location: Right side, bottom of cloak, inside of fold Description: Blue Microscopic Image

3b Sample 3B: Blue Side Down, Right side bottom of cloak, inside fold Azurite: 2CuCO 3  Ca(OH) 2 Blue from Cloak

Sample 2 Location: Base, left side toward the back Description: Green Sample 4 Location: Base, right side toward the back Description: Green Microscopic Image

2d Sample 2D: Green base left Green sample from base

Surprise!!!! Copper acetoarsenite

Sample 5 Location: Flat fold, left side of cloak Description: Rust, metallic, layered, fluorescent under UV light Pyrite? Microscopic Images

We’re no fool!! It is real gold and much more ! Red Ochre: Fe 2 O 3 Red Ochre has been used since prehistoric times. It can be found in volcanic regions or can be produced by heating yellow ochre.

4a Reference spectrum of hide glue Glazy part of paint

Sample 6 Location: Book binding Description: Red, dull Microscopic Images

Sample 7 Location: Bottom of cloak, left side Description: Fiber

7c Sample 7C: Fiber White end, Bottom of cloak

Blue cloak: Azurite Clay Calcium Carbonate Green base: Protein/Copper acetoarsenite Not determined Calcium carbonate Outer Cloak Gold Red Ochre/clay/gypsum Calcium carbonate Protein Red book binding: Red Ochre/clay/gypsum Calcium carbonate Protein

-Mr. Peter Blume, Director of the Ball State Art Museum -Bob Galyen, TAWAS -Ball State Office of the Provost--BSU Teleplex -Michael Kutis, Geology Technician at Ball State --Beth Price, Senior Conservation Scientist, Philadelphia Museum of Art -Dr. Mary Virginia Orna, Scientist-in-Residence, College of New Rochelle