Maya Blue and Franciscan Evangelism

In the first decades of the Franciscan evangelical campaign in Yucatán, Mexico (1540–90), Maya builders and artists directed the construction and pictorial decoration of hundreds of Christian edifices, ranging from small-scale chapels to larger churches and entire monastic complexes, offering a material record of the peninsula’s religious transformation. Strategic color selection and the deployment of Maya blue pigment in particular architectural, iconographic, and liturgical contexts enabled Indigenous catechumens to reconcile post-Tridentine conceptions of divinity with precontact sacred ideologies. By weaving diverse methodologies from the study of visual sources, textual documents, and material characterization techniques, we demonstrate how colonial Maya color theory actively engineered localized Catholicism.

Interactions between Cationic Dye Toluidine Blue and Fibrous Clay Minerals

Interactions between cationic dyes and negatively charged mineral surfaces have long attracted great attention from clay mineralogists, environmental scientists, and chemical engineers. In this study, the interactions between a cationic dye toluidine blue (TB) and palygorskite and sepiolite were investigated under different experimental conditions. The results showed that in addition to cation exchange, the specific surface area (SSA) of the minerals, particularly the formation of dimer molecules on the surface of both minerals, also accounted for the much higher TB uptake in comparison to their cation exchange capacities (CEC). The TB molecules were sorbed to the external surfaces, as no d-spacing expansion was observed in X-ray diffraction analyses. FTIR analyses showed strong interactions between the C=N or N-(CH3)2 group and the mineral surfaces, suggesting net electrostatic interactions if either of these functional groups bears a positive charge. Results from molecular dynamic simulations suggested dense monolayer TB formation on palygorskite because of its limited SSA and large CEC values. In comparison, a loosely dimeric formation was revealed on sepiolite for its large SSA and limited CEC values. Therefore, palygorskite is a better carrier for the sorption of cationic dyes, as evidenced by Maya blue paintings.

An analytical study of the Huexotzinco Codex using X-ray fluorescence, fiber optic reflectance spectroscopy, and portable Fourier-transform infrared spectroscopy

The Huexotzinco Codex is one of the earliest surviving manuscripts from the early colonial period of Mexico. The codex pertains to the legal case of conquistador Hernán Cortés and contains paintings and documents detailing the seizure of Cortés’ personal properties and over-taxation of his Huexotzincan allies by the colonial government in New Spain (present-day Mexico). Eight paintings within the manuscript were subjected to non-invasive analytical techniques revealing the pigment palette and production methodology. The findings of this study show a mixture of pre- and colonial codex production practices as well a unique Maya blue formulation and the identification of a silicate material used as a matrix for an organic yellow dye.

Maya Blue Used in Wall Paintings in Mexican Colonial Convents of the XVI Century

Maya blue is a well-known pre-Hispanic pigment, composed of palygorskite or sepiolite and indigo blue, which was used by various Mesoamerican cultures for centuries. There has been limited research about its continued use during the Viceroyalty period; therefore, the sixteenth century is the perfect period through which to study the continuity of pre-Hispanic traditions. The fact that the indigenous people were active participants in the construction and decoration of convents makes their wall paintings a good sampling material. X-ray fluorescence (XRF), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed in samples of blue found in convents across Puebla, Tlaxcala and Morelos in order to identify whether the numerous hues of blue were achieved with Maya blue or with other pigments. We found no copper (Cu) or cobalt (Co) with the XRF, so several pigments, such as azurite, smalt or verdigris, were discarded. With SEM, we discovered that the micromorphology of certain blues was clearly needle-shaped, suggesting the presence of palygorskite or sepiolite. In addition, we found silicon (Si), magnesium (Mg) and aluminum (Al) by using energy-dispersive X-ray spectroscopy (EDS) in all blue samples, which also suggests the presence of these magnesium-rich clay minerals. With the XRD samples, we verified that the blues were produced with these two clay minerals, thus confirming that several wall paintings were manufactured with Maya blue. These findings confirm that this particular manmade pre-Hispanic pigment, Maya blue, was an important pigment prior to the Viceroyal period.