Study of the copper effect in iron-gall inks after artificial ageing

Establishing the original order of the poems in Harward's Almanac using paleography, codicology, X-ray fluorescence spectroscopy, and statistical analysis

This work presents the results of a transdisciplinary analysis performed on Harward's Almanac (Dublin, 1666), an extremely rare volume currently housed in the National Library of Ireland. The uniqueness and historical value of the Almanac is related to the presence of nineteen handwritten poems, entered by an anonymous scribe. These record textually important English clandestine satire circulating anonymously in Dublin in the late seventeenth and early eighteenth century. Following a comprehensive historical assessment, it appeared evident that the current order of leaves was incorrect. To reconstruct the correct order of the leaves, and hence the likely sequence in which the manuscript poems were inscribed, this study employed a codicological/paleographic analysis complemented by analytical (X-ray fluorescence, XRF) and statistical (Self Organizing Map, SOM) investigation. Specifically, point XRF analysis was carried out for each handwritten page of the Almanac, allowing identification of ink elemental compositions (iron-based ink) and successfully supporting the validity of historical hypotheses on the poems' order of inscription. The statistical organization of XRF data by SOMs allowed easy bi-dimensional visualization of the data set (54 points) and identification of ink similarities, once more validating the historical assessment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40494-023-01107-y.

Non-invasive approximation of elemental composition of historic inks by LA-ICP-MS measurements of bathophenanthroline indicators

The approximated identification of elemental composition of historic iron gall-inks is proposed based on results of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) measurements combined with a quick detection of iron (II) ions. Colorimetric response of test papers soaked with bathophenanthroline (BPhen) allows for detection of iron in the form of red-coloured complex of Fe(II) with BPhen. A co-migration of other elements (Cu, Zn, Pb, Al, K, Na, Mg) into indicators was confirmed by LA-ICP-MS measurements allowing for approximation of chemical diversity of handwritten documents in a totally non-invasive manner in respect to originals. The proposed analytical approach for in-direct studies of unique documents was tested on historic and model samples. The idea of approximation of elemental composition of the historic inks was found promising for purposes of conservation diagnosis towards estimation of corrosiveness of inks and eventual fingerprinting. It has been demonstrated that the presence of Fe as well as other elements (S, Cu and Mn) which are significant for recognition of ink corrosion can be detected in the used indicators extending the possibilities of examining valuable manuscripts in a way that is completely neutral for them.