The invention of printing using movable metal type — at least in Europe — is attributed to Johann Gutenberg of Mainz, in present-day Germany. His discovery profoundly influenced Western culture by allowing, in theory, the ‘mass’ reproduction of religious and secular texts. In practice, however, the printed copies were distributed to workshops throughout Europe to be lavishly embellished, or ‘illuminated’, by hand with headlines and capital letters.
Of the estimated 180 copies of the Bible that Gutenberg produced in three years up to 1455, substantial fragments of 48 survive. Tracey D. Chaplin et al. (Anal. Chem. doi:10.1021/ac050346y) have used Raman spectroscopy — shining laser light onto a sample and analysing the spectrum of the scattered light — to study the chemical composition of the pigments used in the illuminations of seven copies of the Bible from libraries in France, Germany and Britain. Although the style of illumination varies widely between the Bibles, the chemical composition of the pigments used is remarkably similar, pointing to a shared knowledge of dyestuffs across fifteenth-century Europe.
Nine pigments are present, for example, in the King George III Bible (pictured) held in the British Library in London. The chemical composition of seven could be identified conclusively: red (cinnabar or mercury sulphide), blue (azurite, a basic copper carbonate), olive green (malachite, another basic copper carbonate), dark green (verdigris, an organo-copper compound), yellow (lead-tin oxide), black (carbon) and white (calcium carbonate). Copies of the Bible from two German libraries, printed on vellum, also contain the expensive blue pigment lazurite (lapis lazuli) — perhaps indicating commissions from wealthy families.
The authors point out that, alongside the historical interest of their findings, an accurate knowledge of pigment make-up is crucial in helping to preserve and restore such cultural treasures.