Natural minerals and earths with coloring properties have been widely used as artistic pigments since prehistoric times. Despite being extensively studied, the complex chemistry of earth pigments is still unsatisfactory described with respect to their mineralogical and structural variability and origin. In this study, a large group of earth pigments from various geographical locations was investigated using easily accessible spectroscopic techniques and multivariate analysis with the aim to identify distinctive mineralogical and chemical characteristics of natural pigment sources. Portable X-ray fluorescence (p-XRF), Fourier transform infrared spectroscopy (FTIR) and fiberoptic Raman spectroscopy were used for the elemental, molecular and structural characterization of the investigated pigments. Diagnostic spectral features and chemical patterns (fingerprints) were identified and discussed with respect to their geological sources. Due to the occurrence of similar accompanying minerals, it was observed that the differentiation of red and yellow ochers is more challenging compared to green, brown and black pigments. However, for some of the investigated pigments, the presence of certain accessory minerals and/or of certain chemical patterns can have diagnostic value. Principal component analysis (PCA) of the FTIR and XRF data matrices showed promising results in terms of geological attribution, highlighting a promising tool for provenance research. The results of the study demonstrate the potential benefits of this rapid and nondestructive approach for the characterization and differentiation of earth pigments with similar hues coming from different geological sources.

Surgical excision is the most effective treatment of skin carcinomas (basal cell carcinoma or squamous cell carcinoma). Preoperative assessment of tumoral margins plays a decisive role for a successful result. The aim of this work was to evaluate the possibility that hyperspectral imaging could become a valuable tool in solving this problem. Hyperspectral images of 11 histologically diagnosed carcinomas (six basal cell carcinomas and five squamous cell carcinomas) were acquired prior clinical evaluation and surgical excision. The hyperspectral data were then analyzed using a newly developed method for delineating skin cancer tumor margins. This proposed method is based on a segmentation process of the hyperspectral images into regions with similar spectral and spatial features, followed by a machine learning-based data classification process resulting in the generation of classification maps illustrating tumor margins. The Spectral Angle Mapper classifier was used in the data classification process using approximately 37% of the segments as the training sample, the rest being used for testing. The receiver operating characteristic was used as the method for evaluating the performance of the proposed method and the area under the curve as a metric. The results revealed that the performance of the method was very good, with median AUC values of 0.8014 for SCCs, 0.8924 for BCCs, and 0.8930 for normal skin. With AUC values above 0.89 for all types of tissue, the method was considered to have performed very well. In conclusion, hyperspectral imaging can become an objective aid in the preoperative evaluation of carcinoma margins.

This study evaluated both the possible fungal metabolites involved in the degradation of the commercial consolidant known as Paraloid^® B72 and the national artisanal consolidant named transparent dispersion of casein and the deteriorative potential of melanised fungi. Fungi were found to have the capacity to produce organic acids, proteases and esterases when they grow on consolidants, which can be used as nutrients. Mycelia produced by melanised fungi affected the appearance, as well as the integrity, of consolidants applied on painted experimental models and fragments of frescoes. In treatment trials with biocides (Biotin R^®, Biotin T^® and Preventol^® RI 80), the morphology of the consolidants, as well as the vitality of the fungi, were assessed 30 days after the inoculation with melanic fungi. Direct observation, optical microscopy, colourimetry and microbiological analysis highlighted the degradation of the consolidants by fungi and their acquired resistance after biocidal treatments. Biotin R^® applied by brushing on the surface of the consolidants proved to be the most effective treatment, followed by Biotin T^®. Considering the overall results for both Paraloid^® B72 and transparent dispersion of casein, use of Biotin R^® applied by brushing is recommended for preventive conservation.

This article reports the first analytical study carried on some of the oldest surviving examples of Roman wall paintings, discovered so far on the Romanian territory. Dating back to the second century, these decorative polychrome wall painting fragments were found during an archaeological research carried at Ulpia Traiana Sarmizegetusa, and represent the first mural paintings ever found on site. A set of samples was analyzed using various non-destructive and micro-invasive techniques in order to investigate the material composition and explore the painting technique. The employed methodology allowed for an in-depth characterization of the color palette, generally based on mineral pigments such as red earth, celadonite, yellow ochre, calcite, and strontianite. The absence of organic binders and the possibility to differentiate specific spectral features infer the use of a fresco-secco technique. The results obtained provide important data regarding the artistic and technological skill of ancient painters in this part of the Roman Empire, and they significantly contribute to the research and conservation work carried out at this impressive archaeological site.

In this paper we are presenting our approach and workflow for macro photogrammetry as a complementary method for 3D digitization of polychromies on wood support. Macro photogrammetry can be used for detailed documentation of physical damages in painting layers, underlayers or support. For a better presentation of the context, a selection of typical physical damages, relevant to this study, are explained. Two case studies are presented. Two wooden icons realized with different techniques and presenting different types of physical deterioration. The experiments detailed within this paper represent the first epoch of long-term monitoring of the restoration interventions for each of these icons. All the stage of our workflow is thoroughly detailed with acquisition parameters and processing settings in order to better understand the results and where things can be improved. For each icon a full body photogrammetry process is described, followed by macro photogrammetry on smaller selected areas on the icons' surfaces. Macro magnifications of 1 : 1 and 2 : 1 are obtained by using a dedicated macro lens and extension rings. Lighting setups and focus stacking process are also described for a better understanding of the parameters and settings used.