Spektroskopija dokumentinio paveldo autentiškumo tyrimuose: Supraslės vienuolyno raštinės atvejis

Tadas Žižiūnas

Abstract


Straipsnyje pristatoma neverifikuotų rašytinių dokumentų autentiškumo tyrimo metodologija, paremta UV-VIS-NIR atspindžio spektroskopija. Remiantis geležies galo rašalo spalvinėmis savybėmis konstruojamas istorinių rašytinių dokumentų klastojimo, nevienalaikiškumo, korekcijų identifikavimo metodologinis modelis. Sukurta metodologija pritaikyta Supraslės vienuolyno raštinės XVI–XVIII amžių rankraštinių knygų atvejo tyrimui. Tyrimo metu nustatyta, jog dvidešimtyje tirtų dokumentų tomų fiksuotos galimai nevienalaikės teksto dalys. Prieš laboratorinį tyrimą de visu metodu išskirti galimai nevienalaikiai knygų puslapiai keturiais atvejais iš penkių nepasitvirtino. Tai reiškia, jog UV-VIS-NIR atspindžio spektroskopija dėl mažų laiko sąnaudų ir matavimų paprastumo gali būti efektyvus ir nedestruktyvus pirminis dokumento rašalo kaitos įvertinimo metodas. Metodologiškai vienodai pildoma tokių matavimų duomenų bazė galėtų tapti papildomu įrankiu sprendžiant abejotinos kilmės dokumentinio paveldo klausimus.

Spectroscopy for Questioned Documents Examination: Case Study of Suprasl Abbey‘s Chancery

The aim of the article was to create a research methodology for questioned historical documents where UV-VIS-NIR reflectance spectroscopy is used to identify color variations of historical documents written with iron gall ink. Such methodology was introduced because most historical documents are written with iron gall ink. Secondly, iron gall ink is causing various damage to historical documents hence new and effective research methods are needed. Thirdly, such new methodologies should be accessible for humanities and social science where no specific chemical knowledge is needed.
20 volumes of Supraslis abbey office’s historical documents were selected as a case study to test the created methodology. Each book was numbered and labeled with the known provenance. In each book three pages (in the beginning, in the middle and in the end) were selected and two measurements (in the top of the page and in the end) were taken. Also so called Q page (questioned) was de visu selected as different from other pages which turned out 79% not being the case. What is more, all measurement’s exact spots were also micro- photographed and macro – photographed to make sure that the measured ink samples that were selected had no stains, were not damaged or otherwise polluted. Measurements were performed with CRAIC PV 308 spectrophotometer calculating 900 measurements average for one value of ∼1mm2 sample area.
The case study demonstrated that UV-VIS-NIR reflectance spectroscopy can be a very fast and nondestructive tool to investigate historical questioned documents, certain pages of a documenet or even to compare several books from the same or different time periods and place origin. However, effective research require ink color comparison with color maps or other mathematical representation models (e.g. MacAdam’s ellipse). Furthermore, for more precise comparison, big databases with books, origin dates, origin place, spectral data, physical condition and other related parameters are needed.
Keywords: falsification, UV-VIS-NIR spectroscopy, heritage, iron gall ink, questioned documents, methodology, interdisciplinary research


Keywords


dokumentų klastojimas, UV-VIS-NIR spektroskopija, dokumentinis paveldas, rašalo tyrimas, neverifikuoti dokumentai, metodologija, interdisciplininis tyrimas, galo rašalas

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DOI: https://doi.org/10.15388/Knygotyra.2018.70.11815