Agathi Anthoula Kaminari

The analysis of pigments in artworks is crucial for conservation, as it provides a detailed characterization of materials. This information is vital for dating and identification, and it informs potential conservation or restoration efforts. The primary aim of this research was to study the optical behavior of paint mixtures compared to pure pigments using imaging techniques. This addresses a gap in the international literature, which, despite extensively documenting the optical properties of pure pigments, lacks sufficient data on the optical behavior of mixed color layers. This preliminary research aimed also to improve the effectiveness of imaging techniques used to analyze pigments based on their optical behavior. To achieve this, two experimental panels were created according to the specific protocol proposed in the literature (Moutsatsou and Alexopoulou, 2014). These panels featured various paint layer mixtures, made from either oil paints in tubes or handmade mixtures of powder pigments with an organic medium (linseed oil). The methodology employed various non-destructive imaging techniques, such as Hyperspectral Imaging (HSI), Ultraviolet induced Luminescence (UVL), False-Color Infrared Imaging (FCIR) and Colorimetry. Visually the results show the dominance of one pigment over the other, but a spectroscopic analysis is needed. The conclusion is to advance from qualitative visual observation to quantitative results, in the form of spectra. Moreover, hyperspectral imaging is a versatile tool; beyond providing qualitative visual output, it yields quantitative results through the spectral cube.

This study aims to propose a multidisciplinary methodology for the assessment of raw papers made of fibres from annual plants, and to investigate their sheet-forming behaviour and potential for packaging materials for cultural heritage objects or archive collections. The study highlights the effects of dry heating artificial ageing on the mechanical and optical properties of the papers. Their morphology was examined through non-destructive spectral imaging in visible (VIS) and ultraviolet-induced visible luminescence (UVL), colourimetry and glossimetry. SEM and Dino Lite handheld digital microscopy have also been employed. The evaluated raw papers presented durability after ageing, with minor changes in pH, visual characteristics (colour/gloss), and mechanical properties (tensile strength), pointing to the usability of non wood packaging materials. The study can serve as a guide for a multi-faceted diagnostic methodology and in-situ testing for the assessment of newly developed and possibly sustainable packaging materials for sensitive archive collections and cultural heritage objects.

Green organic coatings are developed to be deposited on and protect metallic cultural heritage artefacts from environmental degradation. This research work is carried out through a comparative study of under-development green organic and commercial coatings for indoor and outdoor applications against an artificial ageing environment. Non-destructive techniques, such as Colorimetry, Glossimetry, Eddy-current thickness measurements, and SEM-EDS investigation, are employed to assess the studied bronze substrate-coating mock-up systems’ behavior. The results showed some correlations among the studied parameters, such as the thickness–colour (namely ΔΕ parameter) relationship, while comparative conclusions provide consultant suggestions for cultural heritage conservation applications.

Packaging materials made from polypropylene (PP) can be used to protect cultural heritage objects from damage ensuring their long-life preservation. This research work concerns the assessment of recycled polypropylene hollow chamber sheets as potential packaging materials for archival collections and cultural heritage objects. It was carried out through a multidisciplinary diagnostic methodology combining mechanical methods, non-destructive imaging techniques in visible light (VIS), and ultraviolet-induced visible luminescence (UVL), as well as handheld digital microscopy, colorimetry, glossimetry, and SEM microanalysis. The results showed that the condition and mechanical performance of the specimens are affected by the ageing process.

This paper focuses on the study of the famous royal purple dye. It aims to present a holistic approach by researching historical evidence, both for its use and its production, to highlight the importance of the dye within the Greek area. As a substantial part of information concerning the dyeing procedure of purple dye has been lost during the ages, it is crucial to establish points of documentation and identification. The latter can be achieved through chemical analysis, but as this dye is found on precious’s cultural heritage items, which cannot always be sampled, a non-destructive approach should be considered as more appropriate. At first, the history of the dye purple is presented within the Greek area. Then, samples of purple dye are created based on traditional recipes from the Greek area, in order to compose a profile with the characteristics of purple using non-destructive and imaging techniques, thus emphasizing the importance of applying these techniques for the study of dyes on textiles. The results of the experiments show differences in behavior between the pure gland and the dyed samples, as well as the intensity of the color depending on the dyeing procedure.

Religious panel paintings (icons) play a pivotal role in the rituals of the Eastern Orthodox Christian Church. However, their continuous use often results in physical degradation, prompting remedial interventions. Quite commonly, alterations were treated by simply applying new paint layers directly over the decayed original, while in some cases, old icons were overpainted merely as a means to renovate and modernize them. Therefore, numerous overpainted icons are currently housed in churches, museums, and private collections across Greece. This study focuses on the investigation of a post-Byzantine icon of Christ Pantokrator, which displays extensive overpainting while retaining a few visible fragments of the original composition. The objective was to assess the extent and condition of preservation of the original artwork, to identify materials and techniques used both in the initial painting and in subsequent restoration phases, and to distinguish between those phases. To achieve these aims, a fully non-invasive diagnostic methodology was implemented, including visible light photography, ultraviolet radiation imaging (UVR/UVL), hyperspectral imaging (MuSIS HS), infrared reflectography (IRRef), X-ray radiography, and macroscopic X-ray fluorescence scanning (MA-XRF). The findings confirm that the original painting remains substantially preserved and is of high artistic quality. Moreover, analysis revealed at least two distinct phases of overpainting, likely dating from the 20th century, while the results suggest that the original artwork probably dates to the first half of the 18th century. The study highlights the need to use complementary techniques in order to non-invasively assess complex artifacts like overpainted icons and offers valuable insights into historical restoration practices providing foundation for future conservation planning.