We apply a variety of non-invasive techniques for diagnostics and for assessing the state of conservation of painted surfaces.
These diagnostic activities are made possible thanks to valuable collaborations with research institutes that share our conservation-oriented and non-destructive approach, allowing us to accurately detect delaminations, detachments, voids, cavities, hidden structures, cold spots, rising damp, treatments, previous restorations, alterations, and integrations.
Reflected visible light, reflected infrared, false-color infrared, reflected ultraviolet, and UV-induced visible fluorescence all multispectral investigations contribute to defining the diagnostic and analytical framework of surfaces through the combined and coordinated use of multi-frequency acquisition methods.
The infrared reflectography technique, when applied to paintings, makes it possible under suitable conditions to reveal details hidden beneath the visible paint layer. It can detect the presence of underdrawings or later alterations, revealing stylistic changes, compositional adjustments, or reworkings made during the creative process.
It also helps identify traces of retouching or restoration and provides valuable insight into the technique used by the artist.
In the case of wall paintings, infrared reflectography (IR) can reveal preparatory drawings executed with carbon-based materials (such as charcoal, ink, or pouncing powder), as well as identify overpainting or later restorations carried out in subsequent periods. In some cases, long-wave IR reflectography can penetrate layers of dirt or whitewash to detect the presence of painted surfaces no longer visible to the naked eye.
The false-color infrared (IRFC) image highlights areas created with similar pigments, allowing for their quick identification. Although the technique is not exhaustive for the precise recognition of pictorial materials, it nevertheless enables the mapping of color fields and provides a preliminary characterization of many pigments.
Furthermore, it clearly and effectively reveals all areas that have undergone integrative or restoration interventions.
Ultraviolet fluorescence imaging is one of the techniques developed for the identification of pictorial materials through non-destructive surface diagnostics. In wall paintings, in addition to allowing the preliminary detection of certain materials within the pictorial layers that exhibit characteristic fluorescence, this method is particularly useful for identifying the presence of protective and consolidating treatments.
Compared to UV-induced visible fluorescence, reflected ultraviolet (UV) imaging requires suppressing the visible induced radiation and recording only the portion of UV light that is reflected from the surface.
The most superficial layers of materials tend to absorb UV radiation more strongly. This technique is often used in a complementary and integrated way with induced fluorescence. In conservation studies, it is employed to verify the state of preservation and to map areas of restoration carried out with materials that exhibit low fluorescence in the visible range but show distinctive reflection or absorption characteristics under UV.
Laser Doppler Vibrometry identifies areas of high mobility following the excitation of the analyzed structure, using non-destructive techniques specifically developed to optimize the signal-to-noise ratio.
This technique is analogous to the traditional diagnostic method used by restorers, who manually tap on the surface to locate areas of detachment or movement. Infrared Thermography both passive and active detects thermal discontinuities caused by surface or subsurface defects and by the presence of moisture on walls and structural elements.
We are able to carry out part of the diagnostic work required for our activities independently in our own laboratory, equipped with a Nikon Eclipse E50i Pol polarizing microscope with a Nikon digital imaging system and an ISOMET LSS precision saw.
Our portable instrumentation allows us to perform on-site and in-progress analyses.
This enables us to examine surfaces and capture high-magnification digital microscopy images, both in reflected white light and UV. Additional portable equipment includes Flir thermal cameras, fiber-optic endoscopes, UV lamps, salinometers, hygrometers, and various digital photographic instruments.
