SYDDARTA: new methodology for digitization of deterioration estimation in paintings

ABSTRACT The SYDDARTA project is an on-going European Commission funded initiative under the 7th Framework Programme. Its main objective is the development of a pre-industrial prototype for diagnosing the deterioration of movable art assets. The device combines two different optical techniques for the acquisition of data. On one hand, hyperspectral imaging is implemented by means of electronically tunable filters. On the other, 3D scanning, using structured light projection and capturing is developed. These techniques are integrated in a single piece of equipment, allowing the recording of two optical information streams. Together with multi-sensor data merging and information processing, estimates of artwork deterioration and degradation can be made. In particular, the resulting system will implement two optical channels (3D scanning and short wave infrared (SWIR) hyperspectral imaging) featuring a structured light projector and electronically tunable spectral separators. The system will work in the VIS-NIR range (400-1000nm), and SWIR range (900-2500nm). It will be also portable and user-friendly. Among all possible art work under consideration, Baroque paintings on canvas and wooden panels were selected as the project case studies

Corrosion protection of brown and green patinated bronze

Bronze surfaces, whether bare or patinated, tend to change when exposed to an outdoor atmosphere. Art made of bronze which is exposed to the outdoors is usually artificially patinated. This patina changes when exposed to rain, especially in polluted rain, where sulphuric, nitric or carbonic acids are present. In order to gain optimal protection of different patinas and consequently reduce the patina changes over the time different protection systems were developed, tested and tailored. Three types of patina (brown, green sulphate, and green persulphate) were prepared, protected and subsequently studied. The protections were based on two coatings (i) fluoropolymer based coating (FA-MS) and (ii) newly developed fluoropolymer based coating with addition of mercaptopropyl groups, named as alternative fluoropolymer coating (FA-MS-SH). Both the pure patinas applied on bronze surfaces as well as the bare bronze were electrochemically tested, first unprotected and then following the application of two different types of protection. After the protection was applied to the pa- tinas, the change in colour was defined. Different techniques were utilised in order to define the morphology and structure of the patinas, as well as the change in colour following application of the coating. It was shown that a fluoropolymer coating (FA-MS) provided the most efficient protection to bare bronze and the sulphate patina, while a newly proposed alternative fluoropolymer coating (FA-MS-SH) offered good protection to bare and brown patinated bronze. A mechanism for the protection of bare and patinated bronze was suggested

Composition and spectroscopic properties of historic Cr logwood inks

A basic recipe for making a Cr logwood ink dating to 1847 was adapted in order to obtain hues varying from orange to dark brown. The inks synthesized were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy, liquid chromatography-diode array detection-quadrupole time-of-flight-mass spectrometry, and liquid chromatography-inductively coupled plasma-mass spectrometry to gain insight into the spectroscopic properties of the compounds responsible for the inks colors and to obtain Raman spectra that can be used for their non-invasive identification in works of art and in historic documents. It was observed that hematein and logwood oxidation products are present in the inks and that their relative proportions determine the inks hues. It was also found that relatively small variations in the basic recipe, such as in the temperature that the logwood and K2CrO4 mixture were heated at, gave inks with different hues. The Raman spectra acquired in the laboratory samples were used to characterize the ink used by Vincent van Gogh in Street in Saintes-Maries-de-la-Mer

Investigacion of environmental effects on decay of alizarin in egg tempera paints

TECHNART 2017: Non-destructive and microanalytical techniques in art and cultural heritage, Bilbao, May 2-6, 2017. -- https://www.ehu.eus/en/web/technart2017Peer Reviewe

Material characterisation of a painted beehive panel by advanced spectroscopic and chromatographic techniques in combination with hyperspectral imaging

In this study, a painted beehive panel from the collection of the Slovene Ethnographic Museum was examined with respect to its material composition with the aim to reveal the painting technique. Due to the state of degradation due to outdoor weathering (UV irradiation, rainfall, extreme temperature and humidity fuctuations), as well as past conservation interventions, the object represented a complex analytical challenge. We aimed for non-invasive techniques (FTIR in refection mode, Raman spectroscopy and hyperspectral imaging in the range of 400–2500 nm)however, in order to explore paint layers, cross-sections were also analysed using Raman spectroscopy. FTIR spectroscopy in transmission mode and gas chromatography coupled to mass spectrometry were also used on sample fragments. Various original materials were identifed such as pigments and binders. The surface coating applied during conservation interventions was also characterised. Additionally, organic compounds were found (oxalate, carboxylate), representing transformation products. The potential use of Prussian blue as a background paint layer is discussed