Fig. 4From: XRF elemental analysis of inks in South American manuscripts from 1779 to 1825Manuscript of Mateo Pumacahua (1792): Classification of writing inks using PCA. A brown- annotation on the first sheet; green—the body of the text; red—annotation on the last sheet; B Loadings corresponding to “A”. C Blue—the signature of Mateo Pumacahua; lilac = other signatures; D Loadings corresponding to “C”Back to article page