Physical and Chemical Characterisation of the Pigments of a 17th-Century Mural Painting in the Spanish Caribbean

The arrival of Spaniards in the Caribbean islands introduced to the region the practice of applying pigments onto buildings. The pigments that remain on these buildings may provide data on their historical evolution and essential information for tackling restoration tasks. In this study, a 17th-century mural painting located in the Cathedral of Santo Domingo on the Hispaniola island of the Caribbean is characterised via UV–VIS–NIR, Raman and FTIR spectroscopy, XRD and SEM/EDX. The pigments are found in the older Chapel of Our Lady of Candelaria, currently Chapel of Our Lady of Mercy. The chapel was built in the 17th century by black slave brotherhood and extended by Spaniards. During a recent restoration process of the chapel, remains of mural painting appeared, which were covered by several layers of lime. Five colours were identified: ochre, green, red, blue and white. Moreover, it was determined that this mural painting was made before the end of the 18th century, because many of the materials used were no longer used after the industrialisation of painting. However, since both rutile and anatase appear as a white pigment, a restoration may have been carried out in the 20th century, and it has been painted white.

The ecology and bioactivity of some Greco-Roman medicinal minerals: the case of Melos earth pigments

Mineral compounds, as pigments and therapeutics, appeared regularly in the technical and medical texts of the Greco-Roman (G-R) world. We have referred to them as ‘G-R medicinal minerals’ and we suggest that despite their seeming familiarity, there are actually many unknowns regarding their precise nature and/or purported pharmacological attributes. Earth pigments are part of that group. This paper presents a brief overview of our work over the past twenty years relating to: a. the attempt to locate a select number of them in the places of their origin; b. their chemical/mineralogical characterization; c. the study of their ecology via the identification of the microorganisms surrounding them; d. their testing as antibacterials against known pathogens. In the process, and to fulfil the above, we have developed a novel methodological approach which includes a range of analytical techniques used across many disciplines (mineralogy, geochemistry, DNA extraction and microbiology). This paper focuses on a select number of earth pigments deriving from the island of Melos in the SW Aegean, celebrated in antiquity for its Melian Earth, a white pigment, and asks whether they might display antibacterial activity. We demonstrate that some (but not all) yellow, green and black earth pigments do. We also show that the manner in which they were dispensed (as powders or leachates) was equally important. The results, although preliminary, are informative. Given their use since deep time, earth pigments have never lost their relevance. We suggest that the study of their ecology/mineralogy and potential bioactivity allows for a better understanding of how our perception of them, as both pigments and therapeutics, may have evolved.

A Basic Research for Preservation of Works Exhibited in the Outdoor Sculpture Park - A Scientific Analys is of Painted Work ‘Conversion’ Exhibited in the Cheonmasan Sculpture Park -

Outdoor sculptures of modern art works are being damaged and deteriorated as they are exposed to the outdoor environment due to the nature of exhibition in the outdoor environment, but secure of basic data through the measures for conservation and advanced researches still remain in the early stage. The surface of “Conversion” which is exhibited in the Busan Cheonmasan Sculpture Park has been exfoliated and deteriorated due to outdoor exhibition for a long time, so systematic conservation and management of works are considered necessary. Prior to the conservation and management, this study conducted observation of cross section, analysis of inorganic components, FT-IR, Raman and Py-GC/Mass analysis to examine the nature and type of paints used for the work through a scientific analysis. As a result of analysis, paints used for the “Conversion” include paint mixed with silvery aluminium powder and white pigment, reddish paint mixed with toluidine red, bluish paint that mixed prussian blue and titanium white and mixture of phthalocyanine blue and titanium white. The result is expected to be used as basic data for selecting materials necessary for conservative treatment of and establishing a plan for conservative treatment of the “Conversion”.

Analysis of Characteristics Pigment And Paper Excavated At The Site of Hoeamsa Temple (12th-Century), Korea

One paper fragment and three pigments were excavated from earthenware found in the Hoeamsa Temple site (Historic Site No. 128), which is presumed to have been constructed in the 12th century. This study identifies the types and characteristics of the paper and pigments through methods such as fiber identification, pigment component analysis, and crystal structure analysis. Using the Graff 'C' staining method, the paper fragment is identified as paper-mulberry bast fiber (B. kazinoki Siebold), and according to radiocarbon dating results, the paper is believed to be from the Joseon Dynasty, between 1460 and 1640, which is when the Hoeamsa temple was believed to have been rebuilt. The green pigment consists of cerussite, malachite, and ataccamite, while quartz, muscovite, and illite were detected in the white pigment, and quartz, hematite, illite, and kaolinite were detected in the red pigment. The L* value ranged from 41.59 to 79.05. The white pigment showed the highest brightness value at 79.05, while the green pigment was measured at 58.20 and the red pigment at 41.59. The a* value ranged from -2.25 to 22.75: the a* value of the red pigment was the highest at 22.75, the green pigment was the lowest at -2.25. The b* value ranged from 7.44 to 26.26: the b*value of the red pigment was the highest at 26.26 and the white pigment was the lowest at 7.44.These scientific data identified the raw materials of paper used during the Joseon Dynasty. In addition, the data can be used for repair and restoration of ancient dancheong (traditional Korean decorative coloring on wooden buildings and artifacts) by analyzing the composition of pigments and identifying the characteristics of crystal structure.

Applications of Titanium Dioxide Materials

Titanium dioxide (TiO2) is a stable, non-toxic inorganic material. Because of very high refractive index, TiO2 has been widely used as a white pigment. The optimal particle sizes of TiO2 for pigment applications are around 250 nm. The pigmentary applications of TiO2 can be found in many common products such as paints, plastics, paper and ink. Global titanium dioxide pigment sales have reached several million tons annually. Titanium dioxide is also a semiconducting material. When excited by photons which have energy equal to or higher than the band gap of TiO2, electron/hole pairs can be generated. The dynamics of the photo-generated electron/hole pairs of TiO2 is fundamentally important to its photocatalytic properties. More recently, nano-structured TiO2 has raised a great deal of interests in research after the discoveries of the important potentials for applications. The enormous efforts have been put in the preparation, characterization, scientific understandings, and modifications of the photocatalytic properties of TiO2. The applications of nano-structured TiO2 can be now found in a wide range of areas including electronic materials, energy, environment, health & medicine, catalysts, etc. This chapter has discussed and highlighted the development of the applications of titanium dioxide materials in many of those areas.

Radiocarbon dating of lead white: novel application in the study of polychrome sculpture

Recently, radiocarbon dating underwent considerable technological advances allowing unprecedented sample size downscaling. These achievements introduced novel opportunities in dating cultural heritage objects. Within this pioneering research, the possibility of a direct 14C dating of lead white pigment and organic binder in paint samples was investigated on polychrome sculptures, a foremost artistic expression in human history. The polychromy, an indivisible part of polychrome sculpture, holds a key role in the interpretation and understanding of these artworks. Unlike in other painted artworks, the study of polychromies is repeatedly hampered by repaints and degradation. The omnipresence of lead white within the original polychromy was thus pursued as dating proxy. Thermal decomposition allowed bypassing geologic carbonate interferences caused by the object's support material, while an added solvent extraction successfully removed conservation products. This radiocarbon dating survey of the polychromy from 16 Portuguese medieval limestone sculptures confirmed that some were produced within the proposed chronologies while others were revised. Within this multidisciplinary study, the potential of radiocarbon dating as a complementary source of information about these complex paint systems guiding their interpretation is demonstrated. The challenges of this innovative approach are highlighted and improvements on sampling and sample preparation are discussed.

Analyses and Findings of Unusual Substitute Materials in a Raincoat From WWII

Due to the coating materials used, historic raincoats are vulnerable to degradation and rarely survive long periods of time. The investigated raincoat dating from 1943 is no exception – the coating is unusually stiff and flaking off in areas around folds and cracks. Study into its material composition can contribute to important knowledge of the availability of materials for waterproof clothing during the time of the German occupation of Denmark (1940-1945) when the usual materials for raincoats, cotton fabric and rubber, were in short supply. Optical microscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) identified the fabric to consist of rayon stable fibers and paper yarn, and the coating to be based on cellulose nitrate (CN) lacquer, an unknown plasticizer and titanium white (TiO2). Though the results are atypical for a raincoat, they are in good accordance with the raw materials available in Denmark in 1943. Analysis by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS), and 1H and 13C nuclear magnetic resonance spectroscopy (NMR), identified the plasticiser as poly(1,3-butylene) adipate. Powder X-ray diffraction (PXRD) moreover identified the titanium white pigment as the anatase form. By historical discussion this study argues that IG Farben AG is the likely producer of poly(1,3-butylene) adipate, even though the first known marketing of the plastiticiser is from 1986 where the Swiss firm Ciba-Geigy introduced poly(1,3-butylene) adipate as a plasticiser for PVC cling films under the tradename Reoplex® 346. The finding is an extraordinary example on how advanced the chemical industry was in the early 1940’s when it came to polymer science.

White pigments

White pigments are inorganic pigments, whose optical action is mainly based on non-selective light scattering. White pigments do not show absorption in the range of visible light, but have high scattering power leading to high hiding power in their applications. The greater the difference between the refractive index of the white pigment and that of the surrounding medium, the higher the scattering power.