VINLAND Map

Dating of ink (a Controversy)

Detailed examination of the map at the British Museum in 1967 revealed that the ink was unlike anything the scientific staff there had ever seen. In 1974, with new technology becoming available, Yale sent the map for chemical analysis by forensic specialist Walter McCrone whose team dated the ink to after 1923 due to the presence of anatase (titanium dioxide) –in a rounded crystalline form manufactured for use in pale pigments since the 1920s, which suggests that the "yellowing" of ink on the map was faked.

Although in 1992 Dr. Thomas Cahill of University of California, Davis found natural anatase in a variety of medieval manuscripts, the rounded crystals in the ink from the map were characteristic of the synthetic product.

In July 2002, the authenticity of the map was again challenged. Using Raman spectroscopy, the small remaining traces of black pigment in the ink were confirmed to be carbon-based, which should not have generated the yellowish residue (superficially characteristic of the decay of an iron-based ink) which is all that now survives over most of the length of the map's lines.

All of the other pages of the Historia Tartorum and Speculum historiale were written using standard medieval iron-based ink. Nevertheless, chemist Jacqueline Olin, a retired researcher with the Smithsonian Institution, has conducted experiments which suggest a chain of circumstances that could conceivably have led to the production of the map ink in medieval times (though she herself did not produce finished ink).