DIAGNOSTICS FOR CONSERVATION
SILTEA offers to the experts in the field of conservation of cultural heritage scientific support in the choice of materials and methods.
In particular SILTEA performs chemical and morphological analysis for the characterization of the materials, for the determination of technical features, for the identification of degradation factors of artworks, architectures and archaeological finds. A technical report collects all the data with the interpretation for the client.
Morphological analysis by means of portable optical fibres microscopes. It is possible to collect images at high magnification (from 50X to 500X) in white or UV light.
Qualitative measurements of water content in building materials (covering, plaster, masonry, wood) to evaluate the effects of the rising damp and its possible sources.
DETERMINATION OF WATER ABSORPTION
Measure of the water absorption coefficient following the contact sponge method (developed by CNR-ICVBC, Florence) to evaluate the water repellent treatment efficacy.
(UNI 11432, 2011)
In situ examination of the stratigraphic sequence of painted plasters, from the outer altered layers to the masonry in order to evaluate further laboratory investigations.
IDENTIFICATION OF BIODETERIORATION AGENTS
The identification and classification of biological agents as plants, moss, lichens, algae and fungi are performed by macroscopic and microscopic observations of the surfaces.
The morphological study of samples allows describing their technical features and the state of preservation with images at high magnification (from 50X to 500X) in white or UV light.
CROSS SECTION STRATIGRAPHY
Analysis on cross sections are performed to reconstruct the sequence of layers of paintings and plasters, to determine colors, thickness and features of layers, and to analyse shape and granulometry of inclusions. These data are oriented to determine the technical execution.(UNI 11176, 2006)
PETROGRAPHIC ANALYSIS ON THIN SECTION
The thin sections are observed by an optical polarized microscope to classify natural stones, plasters and mortars, to verify the presence of altered layers and to determine firing temperatures of ceramics.
ESEM EDS ANALYSIS
The Environmental Scanning Electron Microscopy with electron microprobe allows analysing samples of small size. Morphological and chemical data of the full sample or of its cross section are collected simultaneously.
X-RAY FLUORESCENCE (XRF)
Chemical elementary analysis are performed by the measurement of the fluorescence distinctive of each atomic species. Qualitative and semi-quantitative (in weight %) analysis are possible.
Identify and quantification of the minerals in a sample. This technique is useful for the study of plasters, mortars, ceramics, pigments, salts and stones.
The FT-IR spectroscopy helps in the identification of the class of compounds in a sample as carbonates, silicates, sulphates or oxalates and organic compounds (oils, waxes, synthetic polymers).
DETERMINATION OF SOLUBLE SALTS
The content of soluble salts is determined by ion chromatography. The species analysed in mortars and deteriorated plasters are either anionic (chlorides, sulfates, nitrates) or cationic.(UNI 11087, 2003).
DETERMINATION OF WATER CONTENT
The analysis is performed measuring the loss of mass after drying of a sample coming from a wall containing the whole stratigraphy.
(UNI 11085, 2003)
The diagnostic analysis represent a key stage of the conservation process, being a moment for the knowledge of the artwork and its constituent material.
In this video are shown some cases of analysis commissioned by companies working in the restoration field. We show techniques and instrumentation useful for the identification of binders and pigments, for the description of stratigraphy, for the distinction between lime and hydraulic mortar and for the identification of the most compatible material with the original artwork.