ABOUT PAINTING THE TEMPLE

Copan, in Honduras, was one of the largest of the Mayan City States during the classic period. The re-constructed Hieroglyphic staircase contains the longest written inscription from Pre-Columbian America. It's 92 steps tell the story of Copan's rulers up to AD 755.

This is another of Copan's wonders. Underneath Temple 16, in the centre, archaeologists found the perfectly preserved RosaLila Temple. It was still covered in vividly painted stucco unlike the rest of the buildings and sculpture (intricate sculptures, just google) of Copan. It had been maintained and used for an exceptionally long time and when it was finally abandoned, the two storey, multi-roomed structure was carefully preserved and buried intact when a new temple was built.

Physical and Chemical Sciences PhD researcher Rosemary Goodall from the Queensland University of Technology used a new infrared analysis technique called FTIR-ATR (Fourier Transform Infrared-Attenuatted Total Reflectance) spectral imaging to study the red, green and grey paint applied to the stucco masks on the exterior of the building.

This technique has not been used for archaeology before and combined with Raman spectroscopy, Goodall found the chemical "signature" of each mineral in paint samples only millimetres in size. The advantage of FTIR-ATR is that while other techniques provided analysis of a microscopic area, it mapped a larger portion from which the recipe of paint could be more easily deduced.

Since the RosaLila Temple has more than 15 layers of paint and stucco, the mineral make-up of the pigments tells scientists what colours were painted on each layer. The stucco itself became more refined over time and changed in colour from grey to white. Ms. Goodall discovered a green pigment and a pigment of Muscovite mica. Mica is used in paints today to create a shimmer effect and the Maya may have used it to get a sparkle effect on the temple which is the only building found with the mineral. Mica isn't found near Copan so it was probably traded from other Mayan cities like Tikal in Guatamala while Copan was a centre for the obsidian market.

Ms. Goodall now wants to take a portable Raman spectrometer to Copan to do more paint analysis as these tests do not destroy any samples. The research will help stop any further damage to the Copan complex.

The temple has been re-constructed to scale and can be seen in the Sculpture Museum at Copan.
This building was used for a hundred years according to the opening and closing ceremonies dated precisely by the Mayan calendar. While the temple was repainted between 15 and 20 times, Goodall estimates the mica was only used every fourth or fifth repainting. Because the Maya had very regular calendar periods, the research team will look at the paint layers and try to determine if the frequency of use correlates to important dates in the history of Copan's Royalty. The calendar is based on a 20-year period called a Katun and the Katun endings were important times of ceremony in the life of the King.

The team consists of Ms Goodall, her PhD supervisor Peter Fredericks with Dr. Jay Hall (University of Queensland) and Dr Rene Viel (Copan Formative Project, Honduras) directing the long-term UQ-led archaeological field research program at Copan.