Specialists from the National Institute of Anthropology and History
(INAH) have been successfully applied different treatments to stabilize the mural painting at the water tank at Santa Cruz de Santiago de Tlatelolco Imperial College, among them, the use of calcium hydroxide nanoparticles, technique that allows retiring salts produced by humidity.
Considered a unique vestige that reveals the fusion of European and Prehispanic pictorial techniques during early New Spain age, this mural, discovered in 2002 in Mexico City, represents realistic scenes created by indigenous hands in 1555, only 55 years after the Conquest.
Maria del Carmen Castro, responsible of this project explained that since the water deposit is located at the foot of the west façade of the convent, it presents different humidity sources, such as the phreatic surface and nearby hydraulic installations leaks, as well as an adjacent garden.
According to the restorer part INAH National Coordination of Cultural Heritage Conservation (CNCPC), after determining the different salts that affecter the New Spain artwork and analyzing the pictorial technique, restoration methods were defined to retire the whitish veils that covered them.
We cleaned salts away using paper pulp and special solutions. This procedure has resulted very effective because it diminish the amount of salts and restores image clarity.
Among techniques employed stands out the use of calcium hydroxide nanoparticles: they form nets that trap pigments, keeping them away from falling. Application of this method is supervised by Dr. Piero Baglioni, researcher and professor at University of Florence (UNIFI), pioneer in the matter.
Maria del Carmen Castro mentioned that the aforementioned does not mean that we are consolidating all the strata with nanotechnology; it will only be used on the layers we find hard to consolidate. We are also injecting lime to fissures to give support to the 16th century artwork.
As long as there is water in the walls, salts will continue forming. We have dug wells in the external areas of the tank to allow the exit of humidity, concluded Castro.