Conference Agenda

Micro-Spatially Offset Raman Spectroscopy (micro-SORS) is an advanced Raman technique that allows the non-destructive analysis of inner portions of cultural heritage artefacts, providing insights on their composition in a non-destructive way. The contribution delves into the methodological and technological advancements of micro-SORS at the CNR-ISPC Raman Spectroscopy Laboratory in Milan over the past decade. Developed in 2014, micro-SORS has become a versatile tool for characterizing artefacts from various historical periods and cultural contexts. Significant progress has been made in refining instrumentation and methodology, resulting in high-performance micro-SORS prototypes, including benchtop and portable systems. Key topics focus on investigating layered materials (e.g., paintings and painted objects) and studying the diffusion of conservation treatments and decay products into various substrates. The aim is to obtain information about the materials' composition, the efficacy of treatments, and the conservation state of the objects under analysis. Additionally, mapping/imaging micro-SORS has been developed to reconstruct the distribution of compounds hidden by opaque layers, such as concealed text in sealed letters. Lastly, this presentation will cover challenges associated with in-situ micro-SORS analysis, including environmental constraints and data interpretation, and will explore strategies for overcoming these.

Ultramarine Blue (UB) pigment, derived from lapis lazuli, holds a significant place in the history of late medieval and Renaissance Europe, owing to its unusually bright colour and stability. Its prohibitive price, which equalled that of gold, meant that it was only used by estimated artists. In this work we present a non-invasive, multimodal approach to the characterization of the photoluminescent properties of different variants of the pigment. The ultimate goal of this research is to propose a protocol for the identification of UB in artworks thanks to the combination of Raman spectroscopy and time resolved-photoluminescence spectroscopy and imaging.

The 1960s saw the emergence of plastic as an indispensable component in various fields, including art and design. Acrylonitrile-butadiene-styrene (ABS) is widely used by artists and designers for a range of applications including sculptures and decorative pieces. Consequently, the necessity to conserve ABS from deterioration is a crucial issue in the field of cultural heritage preservation. Many studies have highlighted the criticality of the stability of the polybutadiene component when exposed to light. We propose a new multimodal spectroscopic approach to assess the conservation status of plastic design objects. This nondestructive approach combines correlative Brillouin and Raman micro-spectroscopy (BRaMS),

external reflection IR spectroscopy and portable NMR relaxometry. BRaMS is a novel nondestructive technique in the field of heritage conservation, allowing simultaneous monitoring of chemical and mechanical changes occurring at the sample surface. The present study focused on photochemically aged LEGO® bricks made of ABS and aimed to i) correlate chemical and mechanical changes induced by light exposure and ii) introduce a surface degradation index (SDI), measurable in situ by external reflection IR spectroscopy, to assess the state of conservation of plastic artefacts. Finally, non-invasive investigations were carried out on real design objects using the MObile LABoratory (MOLAB) platform.

This study explores the use of hyperspectral imaging (HSI) to monitor the effectiveness of plasma-generated atomic oxygen (AO) treatment for non-invasive cleaning of cultural heritage object. Silk samples dyed with indigo blue, including those soiled with soot to mimic historical artifacts, were treated with plasma-generated atomic oxygen for varying durations. Using HSI with a TWINS birefringent interferometer, diffuse reflectance and light-induced fluorescence are observed. That allowed a precise evaluation of sample degradation avoiding any invasive sample extraction. This research not only contributes to the field of cultural heritage conservation but also enhances understanding of indigo colour degradation processes and the evaluation of non-invasive cleaning techniques on sensitive materials.