**2.1 Description of the studied artworks**

*Heritage*

condition the works of art inherited from his mother Etta, who lost much of the property during the communist period, stored them in small improvised spaces, in boxes, in packages dosed in different spaces of an apartment, in Constanta city.

Quantum program, Image Master™ technology.

analysis of recently restored wall paintings [7].

these works [8].

method [9].

integrity of pigment at surface layers.

This study was intended, also, to find new hypotheses regarding authenticity of the paintings, attribute the artworks to the author or one to the school of painting. For this purpose, were used studies of art history and museology, technical methods, such as: analytical documentation, photographing ultraviolet radiation in the dark room by auto exposure and auto-focus, analyses with Vilber Lourmat

Fluorescence of natural products is an interesting characteristic of many components with application in most fields of biology [1] and the methods of art diagnosis such as the analysis and studies in expertise and conservation [2–4]. Through this UV photography analysis technique, the conservators can carry out identifications and evaluations related to the particularity of pigments [4], the

You can also assess the age differences of the painted surfaces and identify the restoration areas. This analysis shows that based on the contrast intensity, it is possible to implement an automatic segmentation of the UV image of a retouched painting [5]. The UV radiation interacts with the apparent layer, and the technique has proven

to be a nondestructive technique for first evaluation and diagnostic expertise of artworks. UV fluorescence can indeed be used for a preliminary identification of pigments. Some of them are easily distinguished, for example the titanium and zinc white pigments can be recognized with UVR because they display a strong UV absorbance band [6]. In addition, the method is recognized as a useful tool in *in situ*

Also, this fluorescent property of natural pigments starts a new trend in contemporary art such as the fluorescent painting or the conservation problems of

The optical and fluorescence microscopy techniques were used for evaluation of microstructural aspects of painting canvas and the state of degradation and biological activity on the painted surfaces with implications for choosing the conservation

Also, a combined strategy including the air biological contamination and the isolation of microorganisms from the works of art surfaces were evaluated to determine their biodeterioration potential on canvas and painting pigments. The biodegradation of oil paintings is a complex process involving multiple phenomena and dynamic interactions between microorganisms and the substrate. Visible phenomena include: the pigmentation of surfaces, the degradation of colors,

the penetration into the material, and the modification of its resistance.

substrate are of great importance in understanding their degradation [10].

the process of manipulation (transport, relocation) or restoration.

of the microorganisms responsible for biodegradation.

Microorganisms induce successive colonization of painted surfaces. These phenomena are accompanied by the presence of specific metabolism compounds (organic or inorganic acids), or enzymes from the extracellular matrix [9], synthesized according to the type of substrate (lipases, esterases, proteases, cellulases, etc.). The isolation and identification of microorganisms, especially of the fungi type, that have cellulolytic action responsible for biodegradation of works of art with natural

As a result, the details regarding the communities of microorganisms associated with a certain type of painted substrate are of major importance before beginning

Another necessary aspect for a good evaluation and intervention in stopping the degradation process and counteracting its effects is the identification of the abioticmicroclimate environment conditions that favor the installation and development

**220**

Vladimir Yegorovich Makovsky was an important Russian painter. His paintings depict a lyrical, idyllic image of the characters in the compositional scenes, *Girl with the child* (**Figure 1**) being an example in this sense, painted by the artist at the age of 45.

#### **Figure 1.**

*Title of artwork,* Girl with the child*, author Vladimir Yegorovich Makovsky (1846-1920), Signed В. Маковский, dated 1891, oil/canvas, size 70 x 115 cm (cod of painting P17).*

V. E. Makovsky was born in Moscow to the family of a famous artist, one of the founders of the Moscow School of Music, and Eduard I. Makovsky. Ever since childhood, the boy (and his brother, later also a famous painter Konstantin E. Makovsky) had been surrounded by an artistic atmosphere, constantly seeing famous masters visiting his father's house, hearing their arguments, and talking about art, he was imbued with thoughts about his high purpose and, therefore, very early on he felt his calling [11].

Makovsky took the first painting lessons from V. A. Tropinin and at 15, under his leadership, he painted the painting *A Boy Who Sells Kvass* (1861). In 1861–1866, Makovsky studied at Moscow School of painting, sculpture and architecture, where he received good professional training under the guidance of artists E. S. Sorokin and S. K. Zaryanko.

The painter is very famous for his portraits of beautiful young girls and scenes from the rural area, which he masterfully painted, in an almost impressionistic style, with a rather high-speed brush, in visible coughs.

The painting is that of a very young girl dressed in simple clothes from the country and with a diaper on her head, with smooth skin, with red cheeks, and with bare feet on dry and dusty bread. The little girl holds a child in her arms, who is supposed to be her brother. The tones are warm, the scene is very beautiful representing a moment of a hot summer day. To suggest this, the painter used the colors red, white, and yellow ocher in contrast to the very dark green, almost black, of the tree in the background.

Nevertheless, the work of art has been kept in better condition than the other works of the collection, considering that it is 129 years old.

The painting surface shows cuts, cracks, erasures, and losses of pigments in some places. The work is painted in oil on canvas, large dimensions 70 × 115 cm, and is signed В. Маковский with brown on the lower left.

Instrumental methods used here and in all the cases that will follow were: photographing ultraviolet radiation (254 nm, 365 nm) in the dark room by auto exposure and auto-focus, analyzed with Vilber Lourmat Quantum program, Image Master™ technology.

Results from the photograph in the ultraviolet light analysis not only showed that the signature and the paint layer are original (**Figure 2**), but also showed clearly the places of some restoration interventions. The darker areas show the places where made interventions of restoration (**Figure 3**).

During this study, it was found that the work belongs to В. Маковский and not to K. E. Маковский as initially believed.

**223**

**Figure 3.**

*Technical - Experimental Methods Used in Artworks' Expertise*

The subject in the painting entitled A *miracle of Jesus* represents the healing of

The painting surface shows cracks, erasures, and losses of pigments in some places. The work is painted in oil on canvas, large dimensions 86.5 × 72 cm, and is

in Paris, belonging to the early French Baroque. The painter was influenced by Italian painting through the artworks of Italian painters who came to Paris, especially Primaticcio's works. For this reason, his painting was initially attributed to the Italian style, erroneously, when the signature was not known. During the in-depth study with the optical equipment and analysis with ultraviolet light, the signature was discovered, which with the naked eye is not visible, due to the age of the painting surface. It is very interesting that although he loved Italian painting, there are no

The composition presents the moment when Jesus after speaking in the Synagogue in Capernaum goes to the house of Peter where on a bed the woman was lying with a high fever. Jesus touches her hand reducing her to a new life, she rises, blesses Him, and begins to serve those around her. The figures are well outlined

The author is the French painter Laurent de Hyre (27.02.1606–28.12.1656), born

Peter's mother-in-law recorded in Holy Scripture (**Figure 4**).

signed L. de Hyre with dark brown in the center down.

*The ultraviolet light analysis to the painting* Girl with the child*.*

witnesses to prove that the artist was in Italy, ever [12].

*DOI: http://dx.doi.org/10.5772/intechopen.92682*

**Figure 2.** *The ultraviolet light analysis for the signature В. Маковский.*

*Technical - Experimental Methods Used in Artworks' Expertise DOI: http://dx.doi.org/10.5772/intechopen.92682*

*Heritage*

and S. K. Zaryanko.

tree in the background.

technology.

V. E. Makovsky was born in Moscow to the family of a famous artist, one of the founders of the Moscow School of Music, and Eduard I. Makovsky. Ever since childhood, the boy (and his brother, later also a famous painter Konstantin E. Makovsky) had been surrounded by an artistic atmosphere, constantly seeing famous masters visiting his father's house, hearing their arguments, and talking about art, he was imbued with thoughts about his high purpose and, therefore, very early on he felt his calling [11]. Makovsky took the first painting lessons from V. A. Tropinin and at 15, under his leadership, he painted the painting *A Boy Who Sells Kvass* (1861). In 1861–1866, Makovsky studied at Moscow School of painting, sculpture and architecture, where he received good professional training under the guidance of artists E. S. Sorokin

The painter is very famous for his portraits of beautiful young girls and scenes from the rural area, which he masterfully painted, in an almost impressionistic

The painting is that of a very young girl dressed in simple clothes from the country and with a diaper on her head, with smooth skin, with red cheeks, and with bare feet on dry and dusty bread. The little girl holds a child in her arms, who is supposed to be her brother. The tones are warm, the scene is very beautiful representing a moment of a hot summer day. To suggest this, the painter used the colors red, white, and yellow ocher in contrast to the very dark green, almost black, of the

Nevertheless, the work of art has been kept in better condition than the other

The painting surface shows cuts, cracks, erasures, and losses of pigments in some places. The work is painted in oil on canvas, large dimensions 70 × 115 cm,

Instrumental methods used here and in all the cases that will follow were: photographing ultraviolet radiation (254 nm, 365 nm) in the dark room by auto exposure and auto-focus, analyzed with Vilber Lourmat Quantum program, Image Master™

Results from the photograph in the ultraviolet light analysis not only showed that the signature and the paint layer are original (**Figure 2**), but also showed clearly the places of some restoration interventions. The darker areas show the

During this study, it was found that the work belongs to В. Маковский and not

style, with a rather high-speed brush, in visible coughs.

works of the collection, considering that it is 129 years old.

and is signed В. Маковский with brown on the lower left.

places where made interventions of restoration (**Figure 3**).

to K. E. Маковский as initially believed.

*The ultraviolet light analysis for the signature В. Маковский.*

**222**

**Figure 2.**

**Figure 3.** *The ultraviolet light analysis to the painting* Girl with the child*.*

The subject in the painting entitled A *miracle of Jesus* represents the healing of Peter's mother-in-law recorded in Holy Scripture (**Figure 4**).

The painting surface shows cracks, erasures, and losses of pigments in some places. The work is painted in oil on canvas, large dimensions 86.5 × 72 cm, and is signed L. de Hyre with dark brown in the center down.

The author is the French painter Laurent de Hyre (27.02.1606–28.12.1656), born in Paris, belonging to the early French Baroque. The painter was influenced by Italian painting through the artworks of Italian painters who came to Paris, especially Primaticcio's works. For this reason, his painting was initially attributed to the Italian style, erroneously, when the signature was not known. During the in-depth study with the optical equipment and analysis with ultraviolet light, the signature was discovered, which with the naked eye is not visible, due to the age of the painting surface. It is very interesting that although he loved Italian painting, there are no witnesses to prove that the artist was in Italy, ever [12].

The composition presents the moment when Jesus after speaking in the Synagogue in Capernaum goes to the house of Peter where on a bed the woman was lying with a high fever. Jesus touches her hand reducing her to a new life, she rises, blesses Him, and begins to serve those around her. The figures are well outlined

#### **Figure 4.**

*Title of artwork, A* miracle of Jesus*, attributed to Laurent de la Hyre, French School, around 1635, oil/canvas, size 86.5 x 72 cm (cod of painting P10).*

in a clear-dark compositional space that induces dramatic mystery with a strong emotional impact and an energetic contrast between the brightly lit areas and others shaded in shades with predominantly brown chromatic tones of a pathetic religious interest. The influence of the Italian painting can be seen in the lively color and the delicacy with which the characters build, being unique in the French painting from the Baroque period culminating with Simon Vuet. He formed his own style from an early age, emphasizing the beauty of the colors but also their symbolism within the chromatic composition.

In the photos in the ultraviolet light are observed dark traces of restoration, and clear signature (**Figure 5**).

**225**

**Figure 6.**

*Technical - Experimental Methods Used in Artworks' Expertise*

displayed at the Louvre, Hyre having a preference for the religious theme, in the center of his attention is Saints Peter and Paul, the story being important in his compositions. In 1648, La Hyre became a founding member of the French Royal Academy of Painting and Sculpture, being elected one of the 12 elders who had

The religious composition *Adoration of the Shepherds* (**Figure 7**) has as characters figures inspired by daily life: Holy Virgin, pastors and other characters, which makes us consider that the painting was painted at the eighteenth century, compared to the artwork *A miracle of Jesus* (**Figure 6**) whose Baroque characters are inspired by Rome and Ancient Greece, attributed to the seventeenth century, the early period.

management positions in the Academy [13].

*The ultraviolet light analysis to the painting* A miracle of Jesus*.*

*DOI: http://dx.doi.org/10.5772/intechopen.92682*

*The ultraviolet light analysis for the signature L de la Hyre.*

**Figure 5.**

Hyre's paintings are in the Louvre Museum in Paris, Strasbourg, Ruen, and Le Mars. In 1635 he painted the painting of Saint Peter healing the sick, which is *Technical - Experimental Methods Used in Artworks' Expertise DOI: http://dx.doi.org/10.5772/intechopen.92682*

#### **Figure 5.**

*Heritage*

**224**

**Figure 4.**

chromatic composition.

clear signature (**Figure 5**).

*size 86.5 x 72 cm (cod of painting P10).*

in a clear-dark compositional space that induces dramatic mystery with a strong emotional impact and an energetic contrast between the brightly lit areas and others shaded in shades with predominantly brown chromatic tones of a pathetic religious interest. The influence of the Italian painting can be seen in the lively color and the delicacy with which the characters build, being unique in the French painting from the Baroque period culminating with Simon Vuet. He formed his own style from an early age, emphasizing the beauty of the colors but also their symbolism within the

*Title of artwork, A* miracle of Jesus*, attributed to Laurent de la Hyre, French School, around 1635, oil/canvas,* 

In the photos in the ultraviolet light are observed dark traces of restoration, and

Hyre's paintings are in the Louvre Museum in Paris, Strasbourg, Ruen, and Le Mars. In 1635 he painted the painting of Saint Peter healing the sick, which is *The ultraviolet light analysis for the signature L de la Hyre.*

**Figure 6.** *The ultraviolet light analysis to the painting* A miracle of Jesus*.*

displayed at the Louvre, Hyre having a preference for the religious theme, in the center of his attention is Saints Peter and Paul, the story being important in his compositions. In 1648, La Hyre became a founding member of the French Royal Academy of Painting and Sculpture, being elected one of the 12 elders who had management positions in the Academy [13].

The religious composition *Adoration of the Shepherds* (**Figure 7**) has as characters figures inspired by daily life: Holy Virgin, pastors and other characters, which makes us consider that the painting was painted at the eighteenth century, compared to the artwork *A miracle of Jesus* (**Figure 6**) whose Baroque characters are inspired by Rome and Ancient Greece, attributed to the seventeenth century, the early period.

#### **Figure 7.**

*Title of artwork,* Adoration of the Shepherds*, unknown author, French School, around 1770, oil/canvas, size 98.5 x 76 cm (cod of painting P13).*

The painting belongs stylistically to the French Academy in Rome, where most of the painters who painted between 1750 and 1800 Jean Baptiste Marie Pierre and his disciples Louis Durameau or Etienne de Vallee Poussin although the French borrowed the Italian way given a common feature that distinguishes them from Italian painters, in the mannerisms with which they approach the compositions representing the "Adoration of the shepherds," the angels hold a drapery that writes Vervum Caro Factum Est, disposed in the same way above the Virgin Mary, keeping reminiscent of the Rococo French manner. The French Academy in Rome offered to young French artists, by a scholarship, the opportunity to see and copy the masterpieces of antiquity or the Renaissance with which they returned to Paris [14].

Approaching the Italian style meant that the initial expertise was mistaken as belonging to the Italian school, especially since the work has no signature. The optical analyses with ultraviolet light showed the restoration areas (**Figure 8**).

The painting titled *Shepherd boy with sheep in the forest of the castle,* attributed to Wendel Dietterlin*,* presents an idyllic scene of a young shepherd with a bag at his neck, who sits on a stone, at the bank of a river, with a stick in his hand (**Figure 9**). The river divided into two parts the composition of the landscape at sunset. At the distance are the sheep on the other side of the river, over a dense forest and at the top of a hill is a castle. This poetic configuration shows us an idyllic scene with a shepherd resting near the sheep on the riverbank, under the castle on the coast.

Wendel Dietterlin (1550–1599) worked in Strasbourg although he was born in Pfullendorf in Wüttenberg into a family of artists, called Grapp, whose children were still painters. To be distinguished from one of the children bearing the same name he is known as Wendel Dietterlin the Elder. Most of his paintings have been lost, randomly found in different private houses or at auction houses. Few of his painting are clearly signed with both names, a clear example would be "Lazar's Resurrection," dated 1587. He is known more as a designer, engraver, and author of the Treaty of Ornament in Architecture. In Pfullendorf is the castle of Sigmaringen dating from the eleventh century and which served as an inspiration in his artistic works [15].

In some of his engravings, Wendel Dietterlin signs with Wendelinus, who is found in the work *Shepherd with sheep* in the castle forest. The WENDELINUS

**227**

**Figure 9.**

**Figure 8.**

*Technical - Experimental Methods Used in Artworks' Expertise*

*The ultraviolet light analysis to the painting* Adoration of the Shepherds*.*

signature is placed under the foot of one of the subjects and follows a low form, in the dark area of the painting, which makes it difficult to see (**Figure 10**). For this reason, at the initial expertise the signature was not observed, and the landscape was wrongly attributed to the Italian school, which was prolific in landscapes with castle as genre in the sixteenth century as the Flemish. The work, executed in a mannerist style, was studied with optical magnifying devices and subjected to the analysis of the whole surface in ultraviolet light where the signature and the restoration areas were noted. The work has been attributed to the author following the

*Title of artwork,* Shepherd boy with sheep in the forest of the castle*, attributed to Wendel Dietterlin,* 

results of the investigations so far (**Figure 11**).

*German School, around 1580, oil/canvas, 59 x 47 cm (cod of painting P7).*

*DOI: http://dx.doi.org/10.5772/intechopen.92682*

**Figure 7.**

*98.5 x 76 cm (cod of painting P13).*

The painting belongs stylistically to the French Academy in Rome, where most of the painters who painted between 1750 and 1800 Jean Baptiste Marie Pierre and his disciples Louis Durameau or Etienne de Vallee Poussin although the French borrowed the Italian way given a common feature that distinguishes them from Italian painters, in the mannerisms with which they approach the compositions representing the "Adoration of the shepherds," the angels hold a drapery that writes Vervum Caro Factum Est, disposed in the same way above the Virgin Mary, keeping reminiscent of the Rococo French manner. The French Academy in Rome offered to young French artists, by a scholarship, the opportunity to see and copy the masterpieces of

*Title of artwork,* Adoration of the Shepherds*, unknown author, French School, around 1770, oil/canvas, size* 

Approaching the Italian style meant that the initial expertise was mistaken as belonging to the Italian school, especially since the work has no signature. The opti-

The painting titled *Shepherd boy with sheep in the forest of the castle,* attributed to Wendel Dietterlin*,* presents an idyllic scene of a young shepherd with a bag at his neck, who sits on a stone, at the bank of a river, with a stick in his hand (**Figure 9**). The river divided into two parts the composition of the landscape at sunset. At the distance are the sheep on the other side of the river, over a dense forest and at the top of a hill is a castle. This poetic configuration shows us an idyllic scene with a shepherd resting near the sheep on the riverbank, under the castle on the coast. Wendel Dietterlin (1550–1599) worked in Strasbourg although he was born in Pfullendorf in Wüttenberg into a family of artists, called Grapp, whose children were still painters. To be distinguished from one of the children bearing the same name he is known as Wendel Dietterlin the Elder. Most of his paintings have been lost, randomly found in different private houses or at auction houses. Few of his painting are clearly signed with both names, a clear example would be "Lazar's Resurrection," dated 1587. He is known more as a designer, engraver, and author of the Treaty of Ornament in Architecture. In Pfullendorf is the castle of Sigmaringen dating from the

antiquity or the Renaissance with which they returned to Paris [14].

cal analyses with ultraviolet light showed the restoration areas (**Figure 8**).

eleventh century and which served as an inspiration in his artistic works [15]. In some of his engravings, Wendel Dietterlin signs with Wendelinus, who is found in the work *Shepherd with sheep* in the castle forest. The WENDELINUS

**226**

**Figure 8.** *The ultraviolet light analysis to the painting* Adoration of the Shepherds*.*

#### **Figure 9.**

*Title of artwork,* Shepherd boy with sheep in the forest of the castle*, attributed to Wendel Dietterlin, German School, around 1580, oil/canvas, 59 x 47 cm (cod of painting P7).*

signature is placed under the foot of one of the subjects and follows a low form, in the dark area of the painting, which makes it difficult to see (**Figure 10**). For this reason, at the initial expertise the signature was not observed, and the landscape was wrongly attributed to the Italian school, which was prolific in landscapes with castle as genre in the sixteenth century as the Flemish. The work, executed in a mannerist style, was studied with optical magnifying devices and subjected to the analysis of the whole surface in ultraviolet light where the signature and the restoration areas were noted. The work has been attributed to the author following the results of the investigations so far (**Figure 11**).

**Figure 10.** *The ultraviolet light analysis for the signature WENDELINUS.*

**Figure 11.** *The ultraviolet light analysis to the painting* Shepherd boy with sheep in the forest of the castle*.*

All these artworks, which represent main topics for scientific analysis, present conservation interventions made by unauthorized persons. Due to those amateur actions, we can see deformations of the painting support, of the canvas, and traces of varnishes applied unevenly on the painting surface that represent the principal cause of the damage. These bad human interventions led to irreversible chemical phenomena that attacked the original pigments and to the loss of the initial color brightness. Being original paintings, they also keep untouched places that can be the subject of scientific study, without being affected by previous restorations. These virgin surfaces represent a special advantage for dating and authentication. Luckily, these works were painted with very good pigments on natural fiber, linen, or hemp. These superior materials used had the quality of helping the paintings to have a longer life. The processes that have started over time are of a chemical and biological nature. This study aims to find a modern solution to stop harmful actions and repair as much as possible what has been degraded.

**229**

coefficient.

cal details identification.

*Technical - Experimental Methods Used in Artworks' Expertise*

tamination and maintenance measures by air conditioning.

1.Storage of artworks in the quarantine space

removing this to a Petri dish with the culture medium.

[17, 18] was adapted using the formula to Dorohoi, 2000 [19].

where n is the colonies number, S is the plate surface area (cm2

painted surfaces characteristics were collected from a surface of 16 cm<sup>2</sup>

and analyzed under a stereomicroscope and epifluorescence microscope.

sterile cotton swab, from each painting, and 5-mm2

isolation on simple agar culture plates.

15 minutes (Ae 1, Ae 2, Ae 3, Ae 4 samplings).

2.Evaluation of airborne microbial impact

(canvas, wooden frames)

*2.2.1 Analysis techniques and sampling*

**2.2 The state of degradation and biological activity on the painted surfaces**

For the maintenance and conservation of the collection of paintings from the Ovidius University Gallery, a scheme of periodic evaluation of the conditions regarding the microbial load was designed in order to establish the initial decon-

The expertise consists in applying some analysis techniques that include the

3.Evaluation of the state of degradation/integrity of the support materials

For the analysis, four old paintings have been selected, described in Section 2.1,

For each painting, five points were identified for sampling, four of which were on the painted side and the fifth was on the material surface of the canvas (the back side of the painting), see **Table 1**. The sampling was performed using noninvasive techniques, by delicate abrasion using a sterile cotton swab, on a surface, then

In order to identify if there is a source of contamination from the airborne microorganisms' culture media, plates were exposed in the areas of interest for

As a medium of bacteria isolation, Glucose Nutrient Agar, Columbia Blood Agar were used, and Sabouraud Chloramphenicol Agar were used for microfungal

The samples were kept at 24–25°C in Benckmark My Temp digital incubator, and colonies growth was evaluated after 3–5 days. For identifications, colonies morphological details and gram stains were used. Also, automat instrument ViteK 2 BioMerieux was used for automat identification and antibiotic susceptibility testing. The number of colonies forming unit (CFU) from air, by sedimentary methods on Petri dishes was according to EN ISO 1469-1 [16], and Pasquarella methods

Microbial CFU/ m<sup>3</sup> in the air (IMA) = n × 10<sup>4</sup>

The light and epifluorescence microscopy techniques were used for morphologi-

The assessment of the microbiological contamination of the canvas was done by

Samples for biological analyses for the evaluation of canvas structures and

/S ∙ ƺ

canvas samples were also taken

), and ƺ is the time

using a

4.Examination of biological presence/activity on the painted surfaces

with areas showing modifications of the varnish layer and the color layer.

*DOI: http://dx.doi.org/10.5772/intechopen.92682*

following stages:

colonies isolation.

**Figure 10.**

*The ultraviolet light analysis for the signature WENDELINUS.*

**228**

degraded.

**Figure 11.**

All these artworks, which represent main topics for scientific analysis, present conservation interventions made by unauthorized persons. Due to those amateur actions, we can see deformations of the painting support, of the canvas, and traces of varnishes applied unevenly on the painting surface that represent the principal cause of the damage. These bad human interventions led to irreversible chemical phenomena that attacked the original pigments and to the loss of the initial color brightness. Being original paintings, they also keep untouched places that can be the subject of scientific study, without being affected by previous restorations. These virgin surfaces represent a special advantage for dating and authentication. Luckily, these works were painted with very good pigments on natural fiber, linen, or hemp. These superior materials used had the quality of helping the paintings to have a longer life. The processes that have started over time are of a chemical and biological nature. This study aims to find a modern solution to stop harmful actions and repair as much as possible what has been

*The ultraviolet light analysis to the painting* Shepherd boy with sheep in the forest of the castle*.*

## **2.2 The state of degradation and biological activity on the painted surfaces**

For the maintenance and conservation of the collection of paintings from the Ovidius University Gallery, a scheme of periodic evaluation of the conditions regarding the microbial load was designed in order to establish the initial decontamination and maintenance measures by air conditioning.

The expertise consists in applying some analysis techniques that include the following stages:


#### *2.2.1 Analysis techniques and sampling*

For the analysis, four old paintings have been selected, described in Section 2.1, with areas showing modifications of the varnish layer and the color layer.

For each painting, five points were identified for sampling, four of which were on the painted side and the fifth was on the material surface of the canvas (the back side of the painting), see **Table 1**. The sampling was performed using noninvasive techniques, by delicate abrasion using a sterile cotton swab, on a surface, then removing this to a Petri dish with the culture medium.

In order to identify if there is a source of contamination from the airborne microorganisms' culture media, plates were exposed in the areas of interest for 15 minutes (Ae 1, Ae 2, Ae 3, Ae 4 samplings).

As a medium of bacteria isolation, Glucose Nutrient Agar, Columbia Blood Agar were used, and Sabouraud Chloramphenicol Agar were used for microfungal colonies isolation.

The samples were kept at 24–25°C in Benckmark My Temp digital incubator, and colonies growth was evaluated after 3–5 days. For identifications, colonies morphological details and gram stains were used. Also, automat instrument ViteK 2 BioMerieux was used for automat identification and antibiotic susceptibility testing.

The number of colonies forming unit (CFU) from air, by sedimentary methods on Petri dishes was according to EN ISO 1469-1 [16], and Pasquarella methods [17, 18] was adapted using the formula to Dorohoi, 2000 [19].

> Microbial CFU/ m<sup>3</sup> in the air (IMA) = n × 10<sup>4</sup> /S ∙ ƺ

where n is the colonies number, S is the plate surface area (cm2 ), and ƺ is the time coefficient.

The light and epifluorescence microscopy techniques were used for morphological details identification.

Samples for biological analyses for the evaluation of canvas structures and painted surfaces characteristics were collected from a surface of 16 cm<sup>2</sup> using a sterile cotton swab, from each painting, and 5-mm2 canvas samples were also taken and analyzed under a stereomicroscope and epifluorescence microscope.

The assessment of the microbiological contamination of the canvas was done by isolation on simple agar culture plates.


#### **Table 1.**

*Codification of biological samples and the characteristics of the sampling surfaces.*

#### *2.2.2 Indoor airborne microbial exposure assessment*

The air microbiota is influenced by a number of factors: altitude, season, human agglomerated, degree of ventilation, temperature, and relative humidity.

Indoor airborne microbial quantifications are a significant parameter to evaluated healthcare-associated infections. Also, the microbial monitoring accounted for microclimate quality and helped to identify critical situations that require corrective intervention [20]. The level of temperature and relative humidity are favorable conditions for interspecific changes and to the vector spread [19, 21].

Bacterial and fungal contamination was identified at all airborne microorganism's assessment points. The most diverse contamination was found in the small room where the paintings in the collection were stored for evaluation. The large number of bacterial colonies belonging to the same species of gram + bacilli was found in sample Ae3, (**Figure 12**), the colonies having invaded the entire surface of the culture plate.

**231**

**Figure 13.**

**Figure 12.**

*exhibition area.*

*Technical - Experimental Methods Used in Artworks' Expertise*

*2.2.3 The assessment of the support material (canvas) of the paintings*

contain fibers of different sizes in their structure (**Figures 13a–d**).

The study assesses the quality of the initial materials from which the fabrics were made, the arrangement and the quality of the working technique (fabric,

The degree of degradation, the vulnerability of the material resistance depending on the thickness and the quality of the microfilaments, and the sensitization by

After the microscopic examination of the fibers, it was found that the fabrics

*Microbial isolated stains after 15 minutes exposure of cultures plates to airborne microorganisms in the* 

*Fabric images: a) P17, b) P10, c) P13, d) P7; epifluorescence microscopic examination (x 400 magnification).*

*DOI: http://dx.doi.org/10.5772/intechopen.92682*

treatment/canvas preparation).

the biological action were noted.
