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Maurizio Aceto, Maria João Melo, Elisa Calà, Paula Nabais, Rita Araújo 111
ation spectra were obtained. The latter may simulate the absorption spectrum. One of the
species is characterised by an excitation spectrum with a maximum at 535 nm whereas the
second species displays a maximum at 590 nm (Fig. 5). On the other hand, the emission
maxima are similar, 595 and 600 nm, respectively (Fig. 6). When compared to artificially
aged samples of Lasallia pustulata, we find a very good match with the chromophore char-
acterised by excitation (Fig. 7) and emission maxima (Fig. 8) at 590 and 600 nm (chromo-
phore #2), respectively. The same was observed for parchment dyed with Rocella tinctoria
(results not shown). Compared to unaged orcein-treated samples, a 5 nm shift to longer
wavelengths was observed in the emission spectrum (Fig. 8). In summary, a very good
match was obtained with representative spectra found in the original purple parchment
(chromophore #2) and an aged reference sample dyed with Lasallia pustulata.
The results of SERS analysis on the samples from the Vienna Genesis and Cod. Ser. n.
2804 are shown in figure 9. Raman microscopy could disclose the molecular fingerprint for
the fundamental orcein structures, shared by all the amino and hydroxy derivatives, Table
1. The main assignments are described next14; bands 517 cm-1 ascribed to δ(COC), 619 cm-1
attributed to δ(COO), 798 with a shoulder at approx. 820 cm-1 due to ν(CC), ν(CN),
14 Rosi, 2013; Doherty et al., 2014; Melo, 2016.
Fig. 4: Spectrofluorimetry spectra of folium, orchil, the parchment of the Vienna Genesis (folio 1,
page 1) and of Cod. Ser. n. 2804. The spectrum of undyed parchment is included.
Open-Access-Publikation im Sinne der CC-Lizenz BY 4.0
The Vienna Genesis
Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment
- Titel
- The Vienna Genesis
- Untertitel
- Material analysis and conservation of a Late Antique illuminated manuscript on purple parchment
- Herausgeber
- Christa Hofmann
- Verlag
- Böhlau Verlag
- Ort
- Wien
- Datum
- 2020
- Sprache
- englisch
- Lizenz
- CC BY 4.0
- ISBN
- 978-3-205-21058-0
- Abmessungen
- 17.3 x 24.5 cm
- Seiten
- 348