RECENART applies the latest technology in researching fine art, archaeological artefacts and minerals. The team constantly develops existing and new research technology.
PIXE is the most sensitive non-destructive technique to study art objects. The University of Jyväskylä is using PIXE and TES-PIXE. TES-PIXE can be up to 10 times more sensitive than the regular PIXE due to its superior energy resolution. It can help detect elements in parts-per-million concentrations. This trace element information can be crucial in understanding where and how an object was created. The actual dating is often based on the impurities of the components.
In PIXE measurements an energetic ion beam from a small accelerator is guided to the object to be analyzed and emitted ion induced characteristic X-rays are detected. Most typically 2–4 MeV H or He ions are used in the analysis, which can be done either in vacuum or in air using external ion beam. In comparison to SEM-EDS, the bremsstrahlung induced background in the energy spectrum is orders of magnitude smaller and therefore PIXE is much more sensitive in measuring semi-heavy elements. On the other hand, PIXE is not normally suitable for measuring lighter elements than magnesium.
In Jyväskylä 1.7 MV Pelletron accelerator can be used for both conventional and high resolution PIXE measurements. The existing setups allows measurement only in vacuum but starting from mid-2014 also measurements in ambient conditions can be made.
While traditional digital imaging takes three wide wavebands of digital light (red, green and blue), hyperspectral imaging captures multiple narrow wavebands. RECENART has hyperspectral imagers for visible light and near infrared wavebands (VNIR, 450-850 nm) and for short wave infrared (SWIR, 1000 – 1700nm). Fine optical instruments combined with novel computational techniques make it possible to conduct colorimetric studies, determine the substances in the artwork, and reveal the underdrawings which may include erased text and hidden signatures.
Raman- as well as FTIR-spectroscopy can provide the molecular and structural information of the pigment.
Raman microspectrometer allows identifying various compounds based on their characteristic Raman-spectra. Raman spectroscopy is a versatile technique that has frequently been applied for the investigation of art objects. In conservation science, analytical techniques which are non-destructive or micro-destructive are particularly important. Raman spectroscopy is such a technique.
Ultraviolet fluorescence and reflected ultraviolet examination allows repairs, restorations and later retouching to be distinguished.
UV radiation has shorter wavelengths than visible light. Almost any painting analysis usually begins with UV examination. It is a quick and affordable test that can provide useful information and help to determine the next steps in analysis technique.
Reflected UV photography allows the conservator to examine the condition of the varnish layer and may also detect fungal growth.
UV fluorescence photography can reveal the presence of natural resin varnishes, It is also possible to identify any retouchings and over-paintings. For instance the authenticity of the original inscriptions or signatures can be confirmed in the UV fluorescence photography.
Infrared examination enables to study the painting underneath the visible surface and detect the underdrawings.
The infrared examination technique detects highly absorbing carbon-based materials such as graphite, charcoal and ink. Infrared light partly passes through the upper paint layers of the painting. It reveals preparatory drawing which can provide valuable information about the artists’ technique and can also help to solve the problems of attribution.
Moreover, with the help of infrared radiation the researcher can see through the varnish layer, study the painting layers and also discover possible later restorations or changes in the painting.
Stereomicroscope is mainly used to take samples and inspect the materials and paint layers. It allows the examination of painting techniques, condition and details.
USB-microscope is used to take a microphotographs of the researched art object.
Infrared spectrometer allows identifying pigments and binding media based on their characteristic infrared spectra.
FTIR analysis characterizes materials, and is especially useful in recognizing inorganic mixtures. FTIR, as well as Raman spectroscopy, can provide the molecular and structural information about organic and inorganic materials. Both techniques allow non-destructive analysis.
FTIR and Raman spectroscopies are considered complementary techniques. Compared with FTIR, Raman is much less sensitive to organic materials, such as varnishes, binders, and some organic pigments.
X-ray is non-destructive technique which is commonly used for technical examination of paintings in order to assess their condition and learn about the original materials and techniques used by artists.
The technique is very useful for detecting the composition changes, hidden paintings and over-painted areas. This examination technique can reveal the information about the composition and condition of the painting canvases, panels, wooden sculptures, the location, extent and nature of damages like for example tears, holes and internal cracks.
SEM/EDS is most useful for differentiating between pigment look-alikes. For example the same color can consist of different pigments and SEM/EDS can reveal their difference. This may help authenticating and dating works of art. By using SEM material samples can be detected in a very large scale magnifications. X-radiation occurs while studying the samples with SEM. The elements and their amount can be found out by analyzing the radiation with EDS.
Powder diffractometer is used to analyze inorganic materials. X-ray diffraction analysis (XRD) is used to identify crystalline compounds. All crystalline compounds, such as minerals, have unique crystallographic structures and XRD can be used to identify these compounds comparing their diffraction data against a database of known minerals and compounds. XRD is used to identify minerals, rocks, gemstones, corrosion products of metals, old conservation materials (e.g. fillers and colourants) such to mention of few.
Raking light examination assists study of the painting techniques and damages.
Raking light is widely used in the examination of works of art. The art object is illuminated from a light source at oblique angle, almost parallel to the surface of the art object. This method allows us to gain information about the surface topography. Raking light shows for example brush strokes, damages, raised paint and planar deformations. All the features in the painting become more defined due to the shadows they create across the surface of the painting.
X-Ray fluorescence analysis using XRF spectrometers is a commonly used technique for the identification and quantification of elements in a substance. From the elements the pigments used in the art object can be detected.
With light microscopes we can examine various samples and details, which are undetectable to the human eye. In RECENART we use mainly fluorescence and polarized microscopy to look details of the art work.