Identification of iron-gall inks with near-infrared Raman microspectroscopy

Στο καινούργιο τευχος του Journal of Raman Spectroscopy (May 2008), οι Alana S. Lee, Vincent Otieno-Alego & Dudley C. Creagh παρουσιάζουν μια εργασία με τίτλο: "Ταυτοποίηση μελανιών μεταλλικής ακίδας με near-infrared Raman μικρο-φασματοσκοπία μεταλικής Identification of iron-gall inks with near-infrared Raman microspectroscopy ".

In the new Issue of Journal of Raman Spectroscopy (May 2008), Alana S. Lee, Vincent Otieno-Alego and Dudley C. Creagh present a paper titled: "Identification of iron-gall inks with near-infrared Raman microspectroscopy".

Περίληψη/Abstract: The identification of iron-gall inks on a number of 18th, 19th, and 20th century documents and a 12th century manuscript has been conducted using near-infrared Raman microspectroscopy. These historic iron-gall inks were found to display characteristic Raman bands generally occurring around 1475 cm^-1, between 1310 and 1350 cm^-1 (variable), 490-640 cm^-1 (combined broad band), and 400 cm^-1. These bands have promise as analytical spectroscopic markers for in situ non-destructive Raman identification of iron-gall ink on historic collections and were in good agreement with Raman data collected for laboratory-prepared iron-gall ink complexes and inks prepared following traditional iron-gall ink recipes. All historic ink spectra contained a fluorescent background, the degree of which varied between samples.

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All that is iron-ink is not always iron-gall!

Στο προηγούμενο τευχος του Journal of Raman Spectroscopy (April 2008), οι Marina Bicchieri, Michela Monti, Giovanna Piantanida & Armida Sodo παρουσιάζουν μια εργασία με τίτλο: "All that is iron-ink is not always iron-gall!".

In the previous Issue of Journal of Raman Spectroscopy (April 2008), Marina Bicchieri, Michela Monti, Giovanna Piantanida & Armida Sodo present a paper titled: "All that is iron-ink is not always iron-gall!".

Περίληψη/Abstract: A number of different inks were used, with the type and precise composition depending on geographical area and historical period. China, iron-gall and logwood were the most widespread, although a number of other graphic media were also used at particular times and places. Because of a problem encountered while planning the restoration of a manuscript apparently written with different media, we have carried out a systematic characterization of the inks involved. The manuscript (Francesco Maria da Ponticelli, Nova Rhetorica, 18th century) showed alternately, sometimes in the same page, dark-black well-defined inks and reddish-brown smudged ones. The latter ones were very difficult to be read and historians identified it as an iron-gall. Our first investigations of the document revealed that the ink had variable composition, but it always showed some typical features of logwood ink. To obtain a better understanding, we prepared, following ancient recipes, logwood inks with the addition of various metallic (Fe, Cr and Cu) salts or amorphous carbon. Iron-gall ink was also used for comparison and in order to obtain an unambiguous and full characterization of the most widespread inks used in manuscripts. Raman and infrared spectroscopies allowed us to identify the characteristic vibrational features of each prepared medium. These techniques, together with X-ray fluorescence (XRF) and multispectral investigations of the original document led us to hypothesize that iron salts were periodically added to the original logwood ink. These sequences of ink quality can be ascribed to a shortage of ink during the writing of the manuscript. A small amount of iron salt immediately darkens the logwood extract, allowing its prolonged use. The presence of iron complexes produces a reddish-brown coloration and causes ink migration in the paper. Combining all the information, we were able to suggest an appropriate restoration treatment and to choose infrared illumination to maximize the readability of the text.

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