Fig. 5From: An analytical study of the Huexotzinco Codex using X-ray fluorescence, fiber optic reflectance spectroscopy, and portable Fourier-transform infrared spectroscopyDigital photograph of Painting VIII, microscope image of purple bricks from Painting VIII and the respective FORS analysis. Absorption features at 485, 525, and 565 nm with 1st derivative peaks at 495 and 535 nm are consistent with an alum-based cochinealBack to article page