O uso de um código comum de cores em mapas militares pelos impérios coloniais francês, português e espanhol (sécs. XVII-XVIII) e a perda de informações: consequências da degradação documental

Abstract

This text presents bibliographical evidences of the existence and scope of a common color code used on military map-making in three colonial empires from the late 1600s. Apparently deriving from Gautier’s treaty (1687), a set of chromatic standards was used in order to unify the representation of reality in either descriptive or normative documents, and both in metropolis and colonies. In the lusophone world, it was chief engineer Manoel de Azevedo Fortes (1722; 1729) who first incorporated these teachings used in the training of military engineers, professionals whose didactic and professional exchanges helped propagate treaties such as Gautier’s and the specially impactful Buchotte’s (1722). This uniformity in watercolor techniques means today that there is a broad interpretation code, whose effectiveness is threatened by a documentary conservation challenge, specially in regards to green copper pigments such as verdigris: these pigments are not chemically stable and not only they tend to loose their original color but they also may corrode the paper itself, which supports the information. It is precisely this information what is at stake: a “simple” color change is actually a rather complex issue, considering that an originally green area, possibly representing bodies of water for instance, may be incorrectly comprehended as a different terrain, because of its browning. In short, there is a risk of aesthetic and historical information loss as a result of processes of decay of a chemical nature requiring attention of a similar nature.