Reconstructing a Mesoamerican codex

The ancient Mesoamerican codices are amongst the rarest books in the world. Less than twenty still exist in the entire world. In them we find – amongst other things - the histories of the Mixtec people, the rituals of the Aztecs, and the calculations of time of the Maya. Even though these books have been studied for their content for over a hundred years, we still don’t really know how they were made. We, an archaeologist and a chemist from the Netherlands, teamed up to try and understand this production process better, by making our own codices using the right materials (pic 1).
It is clear that the precolonial Mesoamerican codices were made with materials that were not commonly used to make European books. Their main components have been identified by international teams of researchers that used high-tech machines to identify materials without damaging the objects.

Pic 1: Chemist Art Proaño Gaibor and archaeologist Ludo Snijders at work on their reconstructions

Combining this with present day local knowledge of plants makes it possible to create a list of basic ingredients for the making of a precolonial Mexican book. Working with these basic ingredients is not always as simple as it seems. For example we know that many Mesoamerican scribes used cochineal to make a red paint. Cochineal is extracted from cochineal lice that live on cacti (pic 3). Inside the body of the female bugs large concentrations of carminic acid can be found. This substance is bright red. In fact this red is so bright that everyone who has eaten a red M&M has without knowing it been eating insect colourant. Not to worry though, it is completely harmless and one of the best and widespread natural red colourants.

Pic 3: Cochineal bugs on a cactus

One such stabiliser, the one most likely used in precolonial times, is alum. This aluminium compound can be found as a mineral, but can also be extracted from certain plants. While the addition of alum stabilizes the colour of the cochineal paint, it also changes it to a more purple colour. This is because cochineal is not only rather unstable, its colour is very much dependant on the acidity of the solution it is made in. So in order to make a bright red and stable cochineal paint, you need more materials than just the bugs and some water.
For these experiments we made a series of paint outs (pic 5), which are small test samples containing the different paints we made with which we could do some more experiments. These samples were subjected to different processes that could damage the paints, such as water, light and friction. These forms of artificial aging helped to better understand how the paints would behave in the long run and thus which materials were the most likely to have been used in the production of the codices.

Pic 5: Replica of sections of the codex Tonalpouhqui (Vaticanus B)

On the first two we used carbon paper to first trace the outlines of the figures, while on the last replica I used a more authentic process. Here I first divided the page using a watered down cochineal. With a series of squares indicating the position of large features the general composition was laid out. After this the outlines of the figures were drawn using carbon black ink. Once these were dry, they could be coloured in using four colours: a yellow made from a plant called zacatlaxcalli (pic7r), cochineal red, blue or matlali made of Commelina coelestis flowers (pic 7l); and green made by applying a layer of matlali over zacatlaxcalli. After everything was coloured in, the outlines had to be retouched in places where the colour paint had gone over the line to make the whole work look neater.

Pic 7: Commelina coelestis flowers used to make blue paint and wild Zacatlaxcalli used for yellow

All images courtesy of, thanks to and supplied by Ludo Snijders, except for pic 9: photo by Ian Mursell/Mexicolore.

Pic 9: The impressive end result...!