Identification and classification of historical writing inks in spectroscopy: a methodological overview

The identification of the type of ink should be among the primary goals of manuscript description. Several techniques of instrumental analysis are available, and new tools have been appearing on the market, the main development having been to more portability and user friendliness. In this article, we would like to give an overview of several existing methods and of their respective advantages and the results (on the example of a Coptic manuscript) that can be obtained with their help

Laser cleaning of undyed silk: indications of chemical change

Three different undyed, unweighed silk fabrics (new clean, new soiled, and naturally aged) were cleaned with a computer-controlled Q-switched Nd:YAG laser at 532nm in 30 combinations of fluence and pulse numbers. They were studied for chemical change by viscometry, X-ray diffraction, and FIB-SIMS in combination with temperature calculations. While physical changes only occurred above the tested parameters, chemical changes could be detected as low as 0.2 J cm?2 with four pulses. Yellowing was observed at lower and bleaching at higher fluence/pulse number combinations. Melting was observed in naturally aged silk cleaned with 64 pulses at 4.2 J cm?2. The temperature reached at 0.1 J cm?2 is sufficient to evaporate carbon. Excess energy is transferred into the silk substrate causing thermal degradation. Different chemical processes leading to chain scission and to crosslinking seem to occur simultaneously, even at low fluence and pulse number. An increase in pulse numbers also leads to increasing damage