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Mobile Artworks Restoration

Restoration and Conservation Diagnostics of Paintings, Sculptures, Frescoes, Furniture, Carpets, Tapestries, Stuccoes

Dating, Periziedi Estimation, Laboratory Analysis, Non Invasive Micro Analysis, Destructive Analysis, X-Ray Analysis (XRay), Wood Lamp Analysis, Stratigraphic Analysis

Investigations

Diagnostics is of great importance, which is from time to time deepened and studied both using specialized centers and using proprietary instruments and technologies: the investigations in fact allow us to know, before proceeding with the restoration intervention, all the relative aspects. to the characterization of the typology of the materials and the degradation of the works on which it will be necessary to intervene, knowledge that integrates the data of the historical-stylistic study.

 

The company carries out its own stratigraphic investigations and non-invasive investigations such as the examination of the pictorial surfaces with Wood's lamp :

Restoration Typologies of Analisys and Interventions

Examination under UV (Ultraviolet Rays) or Wood's Lamp

 

The Wood lamp discovered by the American physicist Robert William Wood in 1913 is also called the UV lamp and is based on the use of ultraviolet radiation of a particular wavelength (3660 Angstrom). When a substance is hit by this radiation it emits a fluorescence, that is, it gives off a luminescence that is characteristic for each substance. This is due to the fact that when atoms and molecules of the substance are hit by the radiation, which is energy, they absorb it and therefore enter a state of agitation emitting energy in the form of light. Fluorescence is distinguished from phosphorescence (also this phenomenon that involves the emission of light) because the fluorescent materials cease to be luminous when the stimulus that determines their brightness is removed, instead the phosphorescent materials continue to emit light for a certain period even after the end of the stimulus. Wood's lamp has a dark purple almost black fluorescent tube, which emits a dim dark purple light and a certain amount of ultraviolet rays invisible to the human eye.


By projecting a beam of UV rays on the surface of a painting in a semi-dark environment, we will be able to observe how some parts of it light up while others remain dark. This is due to the physical phenomenon of ultraviolet fluorescence in the visible range, that is, the property that some substances have to light up when hit by UV rays. With UV rays it is possible to highlight blurred writing (with reflected ultraviolet) or subsequent retouching and repainting that appear as darker and more opaque spots than the original polychromy (with fluorescence). The original paints generally appear as a semi-transparent milky layer but, as there are some paints whose fluorescence prevents the examination of the underlying layers, the paintings are often stripped prior to examination with UV rays. ultraviolet (uv) is certainly one of the most popular and widespread. This technique is mainly used in the phase of ascertaining the state of deterioration of the work and, more particularly, in verifying the existence and extent of the non-original parts of the pictorial fabric. The different luminosities (fluorescence) observable on a painting 'illuminated' by a UV lamp depend not only on the chemical composition of the various substances that make up the protective varnish and the pictorial layers but also vary according to the time that has elapsed since these materials were applied. In fact, with aging, chemical reactions are formed between binders and pigments that make these compounds more fluorescent, while the more recent pictorial reintegrations where these reactions have not been able to take place appear as opaque (less fluorescent) spots. Signatures and dates must also be observed carefully in uv fluorescence as any alteration, modification or addition can be made evident.

 

 

Non Coeval Signature

 

An apocryphal or non-coeval signature is said, the one left by a hand other than that of the indicated author, therefore an inauthentic signature.

 

The recent invoice means that following the technical and laboratory analyzes carried out, the pictorial material is more recent than the operative years of the artist in question, so there is no temporal compatibility between the age of the pictorial material and the period of production. of the artist.

 

Any verification of authenticity must begin with examinations and analyzes to establish whether the age of the painting, the materials and techniques used are compatible with those used by the artist and with his period of action. First of all we observe the pictorial surface with the magnifying glass to study the patina, the crimping, the canvas, the thickness of the pigments and other characteristics of both the pictorial layer and the support (table, canvas, cardboard, paper). We observe the texture of the canvas, any inscriptions on the frame or on the back of the works, the type and arrangement of the nails. Particularly noteworthy is the signature that would seem the easiest detail to imitate but in reality it has its own graphological setting that is unique to each artist and that the expert by profession is used to knowing. Then we move on to the examination with grazing light and then to that with Wood's lamp to ascertain the age, any restorations, abrasions, pictorial retouches, signatures affixed and therefore not contemporary.


Finally, to the iconographic, compositional and stylistic examination which is based on a series of comparisons and comparisons with certainly certain works of a particular artist in order to identify the salient characteristics of the style. The expert must know the techniques and secrets that the artist under examination used, techniques that can also be changed over the years through stylistic evolutions or involution that have characterized the different periods of his production.

 

In the case of an ancient painting that does not react (does not show) to Wood's lamp when examined by UV rays, this means that several evaluations must be made: is the work perfectly clean of external dust, micro-deposits, surface bacteria? It may happen that some pigments present within the colors used, have created a "compression mixture" between them, that is, they have amalgamated and have given rise to a chemical solidification reaction, altering the natural principles of the pigments.

If this happens, a micro-sampling will be necessary to verify the underlying paint.
For the author's signatures, the dates, any characterizations, are scrupulously analyzed with fluorescence, because every form of alteration, made before or after the work itself, is highlighted.

 

X-Ray Radiography 

The X-ray radiography allows to investigate the deeper structure of the paintings on canvas and board, paper and cardboard: the chiaroscuro values returned on the plate placed in direct contact with the painted surface and hit by the beam of X-rays (appropriately dosed by varying the voltage of the tube) will result as a function of the greater or lesser absorption of radiation by the object under examination. When reading the X-ray plate it is important to keep in mind, in addition to the thickness of the layers, the decisive opacity of the pigments with a strong atomic weight (in particular lead white).
Lighter and darker areas will therefore form on the plate depending on the resistance that the various parts of the object will oppose to the passage of X-rays: at the same thickness, the areas of greater density will appear lighter.

 

The X-ray radiography allows to investigate the deeper structure of the paintings on canvas and board, paper and cardboard: the chiaroscuro values returned on the plate placed in direct contact with the painted surface and hit by the beam of X-rays (appropriately dosed by varying the voltage of the tube) will result as a function of the greater or lesser absorption of radiation by the object under examination. When reading the X-ray plate it is important to keep in mind, in addition to the thickness of the layers, the decisive opacity of the pigments with a strong atomic weight (in particular lead white).
Lighter and darker areas will therefore form on the plate depending on the resistance that the various parts of the object will oppose to the passage of X-rays: at the same thickness, the areas of greater density will appear lighter.

Invasive Investigations - Cross Section and Stratigraphic Analysis

 

The analytical and diagnostic investigation techniques applicable to works of art are usually divided into two broad classes:
- invasive, which require the taking of a sample, i.e. the removal of minimal quantities of material from the work, to be subjected to various tests (chromatography, histochemical staining, etc.);
- non-invasive, which, such as X-ray radiography or infrared reflectography, can be performed directly on the work by interacting with the surfaces through various forms of energy.
Invasive methods are in turn divided into destructive (the first and for a long time the only ones to be used), which involve the modification or destruction of the sample examined and non-destructive which, such as reflectance spectrophotometry or X-ray fluorescence , allow the study of the nature and structure of the sample without it being modified or altered.

 

When the possibility of choosing between the various investigation techniques arises to the solution of a specific problem to be investigated, the current trend is to give as much space as possible to non-invasive techniques. However, it is important to underline that among the techniques that require sampling, only those that require very small samples are used. Sampling, that is the choice of the most significant and representative areas, is arranged in such a way as to limit itself to the truly indispensable samples and to the less important areas in relation to the expressive content of the work. In addition, the samples will be taken, preferably on the margins of existing gaps, by experts and with techniques and tools chosen on a case-by-case basis: scalpels, syringes, adhesive tapes, core drills, brushes, etc.

 

The need? to resort to invasive tests? linked to the solution of specific analytical problems (for example for the identification of organic and inorganic materials, of natural or artificial origin) and to a series of limitations related to non-invasive methods (some imposed by the materials themselves as in the case of X-ray fluorescence X which is activated only on inorganic products).
The destruction or modification of the sample is necessary for example with chromatography which allows to separate and dose the components of a mixture or with microanalyses which provide for the identification of the materials through the observation under the microscope of crystal formations or characteristic colors. as a result of induced chemical reactions.

 

The possibility of keeping the sample intact (invasive non-destructive tests) makes it possible to continuously update it according to the development of the analysis techniques. For this purpose, the manipulation of the sample foresees its incorporation in polyester resin and, in the case of the application to the study of the pictorial structures of the paintings, a cut perpendicular to the surface to allow the study in section (stratigraphic section). This allows to obtain numerous analytical data on the composition of each single layer, on their succession, on any alteration or modification to them, contributing to the development of methods capable of stopping any degradation processes, to the identification of additions or remakes , as well as to clarify some aspects of the constituent materials making significant contributions in the field of attributionary historiography.

 

SOURCES:

Extract from: Artis (Art and Restoration Techniques Interactive Studio), Scientific direction: Manfredi Faldi , Claudio Paolini. Cd Rom produced by a group of European restoration institutes, with the decisive contribution of the European Commission as part of the INFO2000 action program.

 

 

Infrared Spectroscopic Analysis of Materials

It highlights the alteration of the molecules of a material. It can be performed on the original wooden parts of a work (table, frame, frame) to determine the type of wood and age (10/20 years of margin of error) or on other materials, such as pigments or glues. It is carried out on a sample of a few milligrams and can lead to the identification of anachronisms.

Microscopic Analysis of the Pictorial Surface

It allows you to study the signs of aging. We observe the "craquelure", the network of small cracks, to understand if it is natural, artificial, deep or superficial; pigments (artisanal, industrial, purity, crystallinity and size), color loss, hardening, restorations.

Infrared Reflectography

It is an optical investigation method that allows you to study the painting in depth, making any preparatory drawings (7), corrections, grids (8), retouching or counterfeiting visible. The presence of a design under the surface is an indication of the authenticity of a work.

Analysis of the Pictorial Layer Under Grazing Light

With an instrument called a durofleximeter, the drying of the paint is verified, which tends to deform over time. Observation with grazing light highlights the roughness of the surface, allows you to identify repainting or restorations.

SOURCES:

Extract from: Artis (Art and Restoration Techniques Interactive Studio), Scientific Direction: Manfredi FaldiClaudio Paolini. Cd Rom created by a group of European restoration institutes, with the decisive contribution of the European Commission in the context of the INFO action program2000.

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