Next Article in Journal
History and Acoustics of Preaching in Notre-Dame de Paris
Next Article in Special Issue
Compositional Analysis of Greco-Roman Unguentaria Residues from the Michael C. Carlos Museum
Previous Article in Journal
Revitalizing the Canale Maggiore in Parma: Enhancing a Rural Area Through Hydroelectric Power and Historical Preservation
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Heritage
Volume 7
Issue 12
10.3390/heritage7120305
heritage-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Multi-Analytical Characterization of Illuminated Choirbooks from the Royal Audience of Quito

by
Martha Romero-Bastidas
1,2,
Katherine Guacho-Pachacama
3,
Carlos Vásquez-Mora
2,
Fernando Espinoza-Guerra
2,
Rita Díaz-Benalcázar
2,
Johanna Ramírez-Bustamante
2 and
Luis Ramos-Guerrero
4,*
1
Universidad UTE, Facultad de Ciencias de la Ingeniería e Industrias, Carrera de Alimentos, Centro de Investigación de Alimentos (CIAL), Quito 170527, Ecuador
2
Instituto Nacional de Patrimonio Cultural (INPC), Dirección de Investigación e Innovación, Quito 170522, Ecuador
3
Facultad de Ciencias Químicas, Universidad Central del Ecuador, Quito 170521, Ecuador
4
Grupo de Investigación Bio-Quimioinformática, Carrera de Ingeniería Agroindustrial, Facultad de Ingeniería y Ciencias Aplicadas, Universidad de Las Américas (UDLA), Quito 170503, Ecuador
*
Author to whom correspondence should be addressed.
Heritage 2024, 7(12), 6592-6613; https://doi.org/10.3390/heritage7120305
Submission received: 26 September 2024 / Revised: 17 November 2024 / Accepted: 21 November 2024 / Published: 24 November 2024
(This article belongs to the Special Issue Analytical Chemistry for Archaeology and Cultural Heritage)
Browse Figures
Versions Notes

Abstract

:
Choirbooks are historical heritage manuscripts used for the performance of vocal music in religious ceremonies in colonial times. This study aimed to understand the characteristics of choirbook manuscripts produced in the Real Audiencia de Quito during the 17th century. The methodology combined non-invasive techniques, such as infrared false-color imaging (IRFC) and X-ray fluorescence (XRF), together with spot analysis by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). The analytical results revealed the use of pumice, chalk and lime carbonate as support materials in the manufacturing process and surface treatment of the parchment. In the illuminations, three pictorial techniques based on protein, polysaccharide and lipid binders were recognized, establishing that the pigments used with greater regularity in the illuminations were vermilion, minium, verdigris, orpiment, azurite, and indigo, preferably in a pure state. Materials used less regularly were also identified, such as yellow ochre, saffron, smalt, red ochre, and bone black, among others. Regarding the vulnerability of the pictorial materials, it was determined that, although most of the pigments exhibit chemical stability, they present some vulnerabilities associated with their intrinsic composition and the medium that contains them.

1. Introduction

Choirbooks, also known as chant books, are historical heritage manuscripts used for the performance of vocal music in religious ceremonies in colonial times (since the 16th century) in the Americas. They were built using mainly parchments, which are a thin material made from the prepared skin of animals. Choirbooks emerged in Europe in the 15th century and lasted until the 18th century. In the Latin American colonies, including the Royal Audience of Quito, music was introduced into Catholic rituals as a tool for the evangelization of the indigenous people. This led to the creation of valuable illuminated manuscripts in convents, monasteries and churches, facilitating the familiarization of the indigenous people with the medieval and Renaissance European Christian faith.
The elaboration of an illuminated manuscript involved various artists and craftsmen such as parchment makers, tanners, calligraphers, illuminators, and bookbinders, among others. They used a variety of materials such as parchment, paper, leather, wood, pigments, metal sheets, and decorative elements made of bronze, iron or brass [1]. Among all the activities, illumination was highly valued, as it turned books into visually attractive works. Illuminators did not limit themselves only to decorating capital letters with floral or geometric ornamental elements but also included grotesques, fantastic figures, and phytomorphic and zoomorphic representations, reflecting the styles of the time, such as the mannerist grotesque and arabesque decorations, as well as religious scenes.
In Quito, these trades were learned and practiced, which allowed for the local reproduction of choirbooks. The Franciscan College of San Andrés, founded in 1556, was the first educational center that offered instruction to indigenous people in various arts and crafts, including the work of illuminating choirbooks. This institution played a crucial role in the development of a local labor force independent of Spanish influence [2]. This institution persisted until the 17th century but did not maintain its original splendor [3]. Other educational centers in the city also instructed the indigenous people in various trades, generating the formation of skilled artisans, who, in addition to working in the convents, had to establish small workshops to develop their trades, among them the illumination of choirbooks.
Historical contracts show the constant demand for these manuscripts, for example, the 1572 agreement between Bishop Fray Pedro de la Peña and Melchor de Alarcón for the manufacture of parchment choirbooks for the Cathedral Church [4]. The contract details the entire elaboration process, from the making of the parchment to the binding, specifying the materials and characteristics, including the prayers adjusted to the Sevillian ceremonial. Although little is known about the first illuminator, it is presumed that he was passing through the Audience, possibly coming from Peru [5]. In a new contract for the creation and illumination of choirbooks for the Cathedral, the collaboration of Francisco Muñoz, a Spaniard residing in Quito, during the bishop’s term of office, is highlighted [6].
Among the illuminators of the regular orders, Pedro Bedón stands out, a Dominican to whom is attributed the creation of the choirbook elaborated in 1613 for the convent of Santo Domingo, which is the object of study in this research. Bedón received artistic training in Lima and is said to have had contact with painters such as Bitti and Medoro in Colombia. Upon returning to Quito, Bedón also played an important role in local artistic production, organizing the Cofradía de la Virgen del Rosario and overseeing the production of high-quality pictorial art [7].
Also mentioned is Fray Francisco de la Fuente, in charge of illuminating another of the books analyzed, created to commemorate the feast of St. Augustine in 1628. Of Quito origin and member of the order since 1592, Fray Francisco held the position of provincial, standing out for his wise measures for the good management of the religion. Later, in 1673, Fray Francisco de Peña Herrera, a Franciscan cleric known for his illuminating work in several books, joined the list of copyists and illuminators, demonstrating his continuous commitment to the creation and maintenance of illuminated choirbook manuscripts [8].
Finally, Friar Ignatius, an 18th-century Franciscan responsible for an illuminated manuscript entitled “The Nona of the Ascension and Antiphons of the Lord”, is identified. This book, documented in detail in an inventory, shows differences in its execution, suggesting work carried out in two distinct stages, possibly from the XVII and XVIII centuries. On the other hand, archival data evidence the availability of a wide range of pictorial materials in the Quito market [4].
On the other hand, the preservation of these documents has been a constant concern for scientists, historians and curators, as they represent essential historical–cultural testimonies for the construction of the identity of peoples. In addition to their liturgical and musical value, choirbooks are important for their materiality and for the elaboration techniques used, aspects that influence their current state of conservation and the strategies necessary for their future survival.
Material characterization studies on illuminated choirbooks have been carried out with diverse analytical techniques. However, in recent decades, non-invasive and portable methods have been prioritized, such as imaging techniques, X-ray fluorescence (XRF) and Raman spectrometry, among others. These methods are often complemented by scanning electron microscopy (SEM), infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis [9,10,11,12,13] to detect details of both organic and inorganic components of the choirbooks and thus to determine the components of those materials with more accuracy.
On the other hand, several investigations have shown that choirbooks’ deterioration is conditioned by factors such as (a) the vulnerability of parchment, which has a high capacity to absorb moisture due to the rupture of molecular bonds by deprotonation of some collagen side chains, generated by the action of lime during its manufacture, which causes the fibers to bind in the presence of water; once processed, collagen can deteriorate due to oxidation, hydrolysis and denaturation of the molecules [14]; (b) the use of pigments/dyes and inks in the decorations, which may be susceptible to discoloration or transformations caused by exposure to light and air; (c) the frequent handling of these documents; and (d) environmental conditions, such as humidity, temperature and exposure to light, which generate physicochemical transformations in the constituent materials, favoring the growth of fungi, the proliferation of insects and changes in coloration, among other problems [15,16,17]. In addition, other studies have focused on the deterioration processes of the parchment and the materials used in these manuscripts, such as pigments and binders [16,18,19,20]; most of these studies were carried out in European countries.
In the case of the choirbooks produced in the Real Audiencia de Quito, some studies have been carried out in the historiographic, religious and musical fields, but little is known about their materiality and elaboration techniques, and even less about how these aspects have influenced their current conservation. In this regards, this study sought to characterize the materials used in the illuminations and scrolls in five choirbooks produced in the 17th century, to understand the traditions to production technically. The methodology used combines non-invasive techniques, such as infrared false-color imaging (IRFC) and X-ray fluorescence (XRF), together with spot analysis by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). The aim will be to determine the limitations of non-invasive techniques for application in future research, thus avoiding sampling, considering that illuminations in most cases are small in size. The analytical information obtained was related and discussed in terms of the relationship between the deterioration process and the intrinsic properties of the supporting and supported materials, as well as the external factors considering previous studies. Finally, we aim to propose preventive and curative conservation measures for the choirbooks under study, which will be useful for the preservation of similar manuscripts in other parts of the world.

2. Materials and Methods

2.1. Population and Sampling

For this study, it was considered necessary to choose a sample of the population of choirbooks produced in various convents of the city of Quito, which corresponds to the Augustinian, Dominican and Franciscan orders. The criteria used to select the sample in each repository was the presence of choirbooks cataloged as from the XVII century, with an important presence of multicolored decorative illuminations, to know their techniques, materials and conservation status. Also, we considered studying choirbooks from the three orders available to compare the findings. In this regard, five copies were chosen (Table 1).

2.2. Multi-Analytical Methodology

A multi-analytical and multipurpose methodology was developed that combines portable and point prospective techniques, as shown in Figure 1.
Micro samples of parchment with colored materials from the illuminations of 1 mm2 were extracted with a scalpel for each specific analysis.

2.2.1. Technical Photography

A modified Nikon D800 single-lens reflex SLR camera (Nikon Corporation; Tokyo, Japan) in manual mode, a Gigapan Epic Pro tripod to control the automatic positioning of the camera, two xenon lamps placed at a 45° angle as light sources, and a pigment checker to correct the images and compare them with the reference samples were used. The technical photographs were captured in RAW format and with maximum resolution using filters in the ultraviolet and infrared ranges. The images obtained were converted into 16-bit TIF format using Adobe Photoshop software. Processing and calibration were performed according to Kushel’s method [21] and Cosentino’s recommendations [22]. The creation of infrared false-color images (IRFC) was achieved by superimposing the image captured in the infrared range with the corresponding image in the visible range, following the method proposed by Dyer. et al. [23]. RGB channels were exchanged between VIS and IR images (Figure 2) [23]. Finally, for the preliminary identification of pigments and colorants, the visible (VIS) and infrared false-color imaging (IRFC) photographs obtained were compared with the palette of historical reference pigments. Cosentino recommends following standard color management procedures, using tools such as the X-rite ColorChecker Passport to calibrate cameras and ensure accurate color capture. It is suggested to perform white balance and exposure correction using gray patches from the AIC PhD card for visible (VIS), infrared (IR), and ultraviolet reflective (UVR) images. Although there is no official standard for ultraviolet fluorescence (UVF), the use of additional emitters is recommended to ensure proper color balance, and UVF images should be edited with Adobe Camera RAW 7.1, adjusting temperature and tint. For false-color infrared (IRFC) images, the color channels of both visible and infrared images should be digitally edited [22].

2.2.2. X-Ray Fluorescence (XRF)

This non-invasive and portable technique was used to analyze illuminations where pigments of inorganic origin were identified or where the use of mixtures in technical photographs (IRFC) was suspected. A Bruker III SD Tracer XRF instrument (Bruker Corporation; Karlsruhe, Germany) was used, with 60 s readings at a voltage of 40 kV and amperage of 20 mA, dispensing with the use of filters. Spectra were generated using S1PXRF 1.0 software. The chemical elements were identified with Artax 7.2.1.1 software.
A reduction in the current and voltage in an X-ray fluorescence (XRF) analysis lowers the energy of the emitted X-rays, thus reducing their penetration ability into the parchment. This can help to minimize the unwanted contribution of decorations on the verso of an illuminated manuscript, although it is not a definitive solution. Techniques such as 3D mapping with micro-XRF offer a more effective separation of the front and back decorations by acquiring specific depth profiles [24]. In this study, one of the criteria for selecting the illuminations to irradiate was ensuring that there was no illumination on the verso that could cause interference. Additionally, for each case, the parchment was irradiated outside the illuminated area to consider it as a background.

2.2.3. Scanning Electron Microscopy

The samples were analyzed in two ways: directly on the surface and by polished cross-sectioning. For the polished cross-section, the samples were encapsulated in self-curing acrylic and polished using a Struers DP-U2 mineralogical polisher (Struers; Ballerup, Denmark) with alumina sandpaper with grits 180–1500. Micrographs were obtained at 10X and 40X using an Olympus BX-53 microscope (Olympus Corporatio; Tokyo, Japan), equipped with an Olympus DP26 camera. Image processing was carried out using CellSens Dimension software version 1.18. The scanning electron microscope (SEM) used was a Jeol IT300 (Jeol Ltd.; Tokyo, Japan) coupled to an Oxford X-MaxN energy-dispersive X-ray spectrometer (EDS) (Oxford Instruments; Abingdon, UK) with 20 kV current and 65 Pa pressure.

2.2.4. Infrared Spectrometry (FTIR-ATR)

An infrared spectrophotometer with Fourier transform, the Jasco 4200 (Jasco Corporation; Tokyo, Tokyo), with a total reflected attenuation (ATR) accessory was used for the identification of organic and inorganic materials such as pigments, natural colorants, and binders. Wavenumber measurements were made from 500 to 4000 cm−1, and then the infrared spectra of the sample were obtained in percent transmittance. The software used for the analysis of the spectra was Spectra Manager 2.10.01.

3. Results and Discussion

3.1. The Parchment

SEM-EDX microchemical analysis of the parchment samples revealed a thin layer composed mainly of calcium carbonate, a product of the production technology, linked to the use of calcium hydroxide (slaked lime) during the waxing and preparation process to give it a whiter surface and an alkaline pH, making it more resistant to attack by acids and microorganisms [11,25]. The homogeneous concentration of sulfur is due to the use of a mixture of calcium hydroxide and sodium sulfite to accelerate the waxing. Traces of aluminum and silicon were also evidenced, related to the use of pumice stone during the polishing of the parchment to obtain a smooth surface suitable for writing, as well as traces of potassium, sodium and chlorine related to the use of salts used to prevent putrefaction [26] (Table 2). Analytical results suggest a homogeneous parchment production technology in the territory of the Real Audiencia de Quito, characterized by the surface treatment of both sides of the parchment, typical of the German–French manufacturing system, which aimed to achieve a high-quality finish, ideal for artistic texts such as illuminated manuscripts [27]. To investigate the degradations of the parchment, FTIR-ATR spectra were compared. In the five folios, characteristic lipid bands were identified in the range of 2900 to 2800 cm−1, corresponding to the CH stretching of methyl and methylene of the carbon chain moieties. In the range from 1000 to 1250 cm−1, bands related to the C-O stretching of the ester bonds of triacylglycerides were recorded. Between 1650 and 1500 cm−1, bands characteristic of proteins were distinguished, corresponding to amide I (C=O stretching) and amide II (C-N stretching with N-H bending mode) vibrations. The amide III band was detected around 1234 cm−1, along with the vibrations associated with the bands of an amide. The shift in the amide II band corresponds to an increase in the separation of the amide I and II bands, which alludes to coiled-coil helix conversion, i.e., the transformation of collagen to gelatin, evidencing deterioration processes by gelatinization of the parchment in all the papers (Figure 3) [28,29].

3.2. Red and Orange Illuminations

Red and orange illuminations generated yellow-toned IRFC images with a subtle difference in color intensity, preliminarily identified as vermilion (HgS) or minium (Pb3O4) (Figure 4a,b) [22,30,31]. SEM analysis of the thin sections confirmed the use of vermilion in the reds and pure minium or mixtures of vermilion and minium, with tonality variations according to the proportion of pigments in the mixture (Figure 4c,d). Also, traces of calcium (Ca), silicon (Si), aluminum (Al), and potassium (K) were found, possibly associated with the surface treatment of the parchment (Table 2).

3.3. Blue Illuminations

Three distinct shades were identified in the blue illuminations, which generated various IRFC images. The dark shade generated a transparent red IRFC image consistent with indigo (Figure 5a). The other less dark shade of blue exhibited an opaque red IRFC image characteristic of azurite (Figure 5b) [22,32]. Finally, the light and intense blue hue did not result in a significant change in IRFC (Figure 5c).T
XRF, SEM-EDS and FTIR-ATR analyses provided valuable information on the chemical composition of the pictorial materials used in the illuminations, supporting the preliminary results. In the case of the dark blue hue, the FTIR-ATR spectra revealed bands at a peak of 1670 cm−1 attributed to the stretching vibrations of the imine C=N group, as well as the C-C stretching vibrations of the aromatic rings of indigotine, the main component of natural indigo responsible for the blue color, around 1461 cm−1, which confirmed the use of this natural dye (Figure 6c) [33]. On the other hand, for the less dark blue tones in which azurite was identified, the SEM-EDX analysis determined the presence of a single layer arranged directly on the parchment, with heterogeneous granulometry, highlighting the presence of copper (Cu), carbon (C) and oxygen (O), which agrees with the chemical structure of the cited pigment, Cu3(CO3)2(OH)2. In addition, in the SA1 book, low levels of lead were found, suggesting the use of lead white mixed with azurite (Table 2, Figure 6a).
Finally, in the shades where it was not possible to identify the pigment by IRFC, XRF and EDS spectra showed significant signals of cobalt (Co), arsenic (As) and silicon (Si) (Table 2, Figure 6b) [34]. Chemical composition is consistent with smalt. The amounts of iron found in the pigments were the same as in the parchment. In this regard, they were not associated with them.

3.4. Green Illuminations

Overall, dark green illuminations generated blue IRFC images that could correspond with malachite or verdigris (Figure 7a,b), in addition to other yellowish-green illuminations that produced IRFC images with a color that made their identification not possible (Figure 7c). Meanwhile, the XRF analysis identified copper (Cu) as the main element.
In the SEM-EDX analysis of the dark green and yellowish-green samples, the main element was copper (Cu), aligned with the possible presence of malachite [CuCO3.Cu(OH)2] or verdigris [Cu(CH3COO)2·H2O]. However, in the dark green samples, other secondary components were observed, such as calcium (Ca), phosphorus (P), and silicon (Si) with significant concentrations, suggesting a combination of copper green pigment with lime white (CaCO3), bone black (Ca-P2O5) [22], and silica (SiO2) [35]. On the other hand, in the yellowish-green illuminations, XRF and SEM-EDS analyses identified arsenic (As) and sulfur (S) as the main elements, which suggests the use of orpiment (AsS) in a mixture with malachite/verdigris (Table 2) (Figure 8). FTIR analysis of the samples from the choirbooks STD1 and STD2 shows peaks of carboxylate functional groups (1563 cm−1 for the antisymmetric C=O stretching and 1388 cm−1 for the symmetric C-O stretching), which corresponds with the presence of verdigris.

3.5. Yellow Illuminations

The illuminations of yellow tones, when analyzed by IRFC images, showed a fainter hue. Although the color change is not highly representative, it suggests the possible presence of orpiment or saffron. The presence of orpiment (As2S3) was subsequently confirmed in SEM-EDS analysis by the arsenic (As) and sulfur (S) peaks in the spectra [31]. The high percentages of silicon point to the use of natural orpiment mixed with ground glass (Table 2) [35].
On the other hand, in the STD2 book, in the FTIR-ATR spectrum, bands were observed, such as the stretching vibration of the OH groups at 3355 cm−1, CH stretching vibrations of methyl and methylene at 2923 and 2853 cm−1, C=O stretching associated with the crocetin ester content at 1710 and 1745 cm−1, and others related to the crocin content in saffron at 1643 cm−1. A band was also identified at 1015 cm−1 corresponding to the vibration of the C-O bond in saffron, attributable to the gentiobiose present in the crocin structure or to the C-O bond in gum arabic monosaccharides [36] (Figure 9c, Table 2). The abundant presence of iron (Fe) inferred the use of yellow ochre mixed with saffron.

3.6. Violet Illuminations

The violet illuminations in the books produced lighter brown IRFC images, suggesting the use of carmine, an organic dye extracted from the Dactylopius coccus (Figure 10a,b). This finding was confirmed by FTIR-ATR analysis. The spectra showed an absorption band at 1628 cm−1 related to C=O stretching in the anthraquinone ring, as well as bands at 1454, 1418, 1240 and 1033 cm−1 corresponding to C-C stretching, O-H bending, the C-O of carboxylic acid and the C-O-C of glucose residue [37,38] (Figure 10c). On the other hand, spot analysis by SEM-EDS also confirmed the presence of lead in the STD2 and SF2 books, suggesting the use of minium [39]. It is important to note that carmine can change color depending on the pH of the medium, from orange to purple (Table 2) [40].

3.7. Gilding Illuminations

Gilding-colored illuminations were found in the SF1, STD2 and SF2 books, which, according to XRF and SEM-EDS analysis, indicate the use of gold leaf. The high percentage of gold in the samples (90–94%) suggests high-purity alluvial gold. On the other hand, in the LC-STD2 book, it was observed that the gold leaf was deposited on a reddish-brown preparation layer, with significant concentrations of aluminum and silica, suggesting the presence of clay. The opaque characteristics of the gold leaf surface indicate that a burnishing process was not performed, as well as the use of clay particle binder, which acts as a bread adhesive (egg albumin or drying oil) (Figure 11, Table 2).

3.8. Binders

The production of illuminations considered the use of egg in the binders because of the brightness generated in the illuminations. Both the yolk and the white of the egg are used together with gums, resins and varnished; however, the egg yolk was less used because it is less adherent, fragile and causes stains. Also, the use of small amounts of oil in the binders has been reported [41]. Indeed, three types of binders were identified by FTIR-ATR in the choirbooks: egg, oil and gum arabic (Table 2). The infrared spectra of the samples show bands that can be attributed to the proteins and lipids of the egg and oil used in the binders. Bands characteristic to lipids were observed in the 2900–2800 cm−1 region, corresponding to the CH stretching of methyl and methylene. Bands in the 1650–1500 cm−1 region are associated with the vibrational stretching of amide I (C=O stretching) and amide II (C-N stretching and N-H bending). Additionally, a band at 1237 cm−1 was identified, attributed to the N-H bending of amide III [42]. In the region of 1000–1250 cm−1, the bands are attributed to the C-O stretching of the ester bonds of triacylglycerides, while in the FTIR spectrum for gum arabic, the characteristic bands of OH stretching between 3300 and 3355 cm−1, attributable to monosaccharides were observed together with those of the C-H stretching vibrations between 2921 and 2027 cm−1 as well as asymmetric C=O stretching vibrations between 1600 and 1636 cm−1, corresponding to the carboxylic acid groups.
Table 3 presents a summary of the pictorial materials identified in the illuminations of this study. These results are consistent with historiographical data that reveal the frequent investment in materials essential to the creation of choirbooks in colonial Quito, highlighting the great variety of materials that made the existence of these volumes possible. The disparity in the materials found in the choirbooks is remarkable. Book STD2, attributed to Fray Pedro Bedón, stands out not only for the quantity of pigments and dyes identified, which amounts to ten, but also for the exceptional quality of its execution. Among the pigments and dyes identified in this volume are saffron, indigo, carmine, orpiment, minium, lime white, yellow ochre, vermilion, azurite, and verdigris. These pictorial materials were used both in their pure state and in various mixtures. Except for orpiment, all were recommended by Pacheco and Palomino in their art treatises for specific applications on parchment. Palomino classifies them as “accidental” colors. Olmos and Pacheco describe them as “fine, thin and high”, destined for delicate and precious things such as illuminations [43].
The rich palette of watercolors reveals the conscious choice of materials by their executors; in the case of Fray Pedro Bedón, we can appreciate his deep knowledge and mastery of the pictorial technique, probably acquired from his teachers, the Italian painters Bernardo Bitti and Angelino Medoro, who, with their mannerist style and their handling of a multiplicity of colors, significantly influenced his artistic formation. Fray Pedro Bedón not only adopted these techniques but also reproduced and perfected them over the years, demonstrating exceptional skill and mastery. His ability to combine these pigments and dyes, together with the use of gum arabic as a binder in the watercolor technique, allowed the creation of illuminations of great luminosity and transparency. This technique, recommended by Pacheco, Palomino and others due to its multiple advantages, such as quick drying, ease of handling and reduction in the use of toxic solvents, was widely used by European illuminators from the 17th century and perfected in the Real Audiencia de Quito [44].
Continuing the discussion, the SF1 and SF2 illuminations also presented a rich palette. Nine pigments and colorants were identified and used in pure states and combinations. The binder found was oil, suggesting the use of the oil technique. This choice is not common in parchments due to its technical disadvantages, such as slow drying, viscous consistency, and rigidity, among others. These aspects indicate a limited knowledge of the techniques used in the illuminations on parchment by the authors of these works. Finally, regarding the illuminations of the STD1 and SA1 choirbooks, although they present a more limited chromatic palette, as well as the fact that, in STD1, the use of mixtures is not observed, they reveal a technical mastery by their authors. In both cases, the presence of egg albumen was identified, indicating that they were made with tempera. This pictorial technique also offered satisfactory results within the illuminators, since, like watercolor, it guaranteed rapid drying, facilitated handling, was lighter in weight, and reduced the use of toxic solvents, properties known to Pacheco; hence, in his treatise on painting, he proposed tempera as an alternative for those who prefer to purify and grind the colors without using a binder such as gum [43].

3.9. Vulnerability and Conservation Criteria

This section will analyze the pathologies or lesions identified in the choirbooks and their relationship with the intrinsic properties of the supporting material (parchment) and supported material (binders, pigment, and colorants), as well as the external factors that influence the kinetics of the deterioration processes. The objective is to define conservation guidelines for these choirbooks as well as for other historical documents with similar characteristics.

3.9.1. The Parchment

Pathologies such as stiffness resulting in cracking or fractures and loss of mechanical strength have been identified. Several studies have related these pathologies to the oxidation processes of the collagen molecules of the parchment. These processes produce changes in the molecular structure, such as bond breaking, modification of functional groups, formation of free radicals, loss of helical structure and formation of oxidation products [16,17,45].
Another group of conditions includes trauma such as swelling and enlargement, which have resulted in visible deformities and distortions; changes in tissue texture, where collagen fibers are weakened, becoming softer or gelatinous; and staining and discoloration due to the breakdown of organic components. These conditions may be associated with collagen hydrolysis caused mainly by acids [46]. The most common sources of these contaminants are atmospheric agents, which, upon interacting with water, penetrate the tissues and react with the chemical bonds of collagen. This results in the breakdown of peptide bonds, the formation of smaller polypeptide molecules, and the loss of the three-dimensional structure of collagen, as well as its cohesion [16,47].
Another set of deformities such as loss of stiffness, changes in dimensions by expansion–contraction, and loss of toughness can be linked to the gelatinization of collagen revealed by FTIR spectra. Sharma and Bohidar confirmed that this deterioration process involves the loss of the triple-helical structure due to the denaturation of collagen due to internal hydrogen bonding in the presence of water [46]. When the collagen molecules in the parchment undergo gelatinization, a fundamental transformation in the structure and properties of collagen occurs. This process involves denaturation and hydrolysis of peptide bonds, resulting in the formation of gelatin. The denaturation of collagen causes the parchment to lose its original characteristics of flexibility, strength, and durability, making it more susceptible to other deterioration processes, such as oxidation, hydrolysis, and biodeterioration [28,48].
Finally, another group of pathologies such as discoloration, pigmentation, fragility, texture changes, and swelling of parchment can be associated with microbiological action caused by fungi and bacteria with collagen and proteolytic activity that can hydrolyze the collagen fibers and protein molecules of the parchment, modify the inorganic components or produce pigments that cause discoloration [15].
Because of the above-mentioned vulnerability of parchment, it is imperative to implement conservation practices such as (1) maintaining stable environmental conditions, with moderate temperatures and controlled relative humidity, to prevent fluctuations that could accelerate the degradation processes by oxidation, hydrolysis and gelatinization of collagen. In this regard, the Standards recommends a relative humidity of between 45% and 55% and a temperature range of 18 °C to 22 °C for parchment, as well as, relative humidity fluctuations should not exceed ±5%, and daily temperature variations should not exceed ±2 °C [49,50]. (2) The exposure of parchment to atmospheric pollutants, especially acids present in pollution, should be minimized to reduce the risk of hydrolysis and other deterioration processes. (3) Avoiding exposure of the parchment to light, especially ultraviolet light, helps to prevent oxidation and reduces the overall rate of degradation. (4) Minimizing the exposure of parchment to moisture is crucial, as water plays a key role in hydrolysis. (5) Handling parchment with clean gloves and avoiding touching unnecessary areas helps minimize the transfer of oils and contaminants that could accelerate degradation. (6) Using storage materials that are non-acidic and free of chemical components that could accelerate collagen degradation is essential to preserve the integrity of the parchment. (7) Performing periodic evaluations of the condition of the parchment by conservation professionals allows the detection of early signs of deterioration, facilitating the timely implementation of corrective measures. It is also vital to implement cleaning and disinfection practices to prevent the proliferation of fungi and bacteria.

3.9.2. The Binders

Binders usually contain egg; therefore, the degradation process of proteins could take place. This process includes the lost of amino acids like methionine (Met), lysine (Lys), and tyrosine (Tyr). Additionally, structural changes in the proteins are observed, with a decrease in α-helices and an increase in β-sheets and random coils, indicating a transition toward disordered structures [51]. Furthermore, the effects of UV radiation, temperature, and humidity on egg-based paintings have been studied, showing that proteins break down in the presence of these factors, especially in media containing yolk due to its high sulfur content [52]. Gum arabic, in environments with excessive humidity, could result in swelling, deformation, or loss of adhesion between the pictorial layer and the parchment, due to its solubility in water.

3.9.3. Pigments and Dyes

In some illuminations where vermilion was identified, chromatic changes (blackening) were observed, which have been related to the photosensitivity of the pigment when it is agglutinated with tempera [53]. Hypotheses about the mechanisms responsible for this pathology have been proposed; however, the experimental data were not consistent with the observed chromatic variation [54,55,56,57,58,59]. In recent years Elert and Cardell (2019) were able to demonstrate that the darkening is a product of a thin layer of metallic mercury deposited on the surface of the pigment resulting from direct exposure to sunlight and humidity [60].
Regarding the use of orpiment (AsS) in illuminations, it is observed that it has undergone darkening processes, most likely related to sulfide ions (S2−) which are unstable and tend to decompose slowly when exposed to air, leading to the formation of degradation products such as PbO2 and lead sulfide (PbS). In addition, these ions, when in contact with pigments such as minium, lead white, azurite and malachite containing lead and copper, can trigger a reaction that results in the formation of black sulfides [61]. Like vermilion, orpiment is toxic due to the arsenic it contains, so its presence and handling today often require specific precautions due to its toxic properties. Azurite and malachite are two forms of basic copper carbonate, CuCO3.Cu(OH)2, which have also undergone transformation processes due to their susceptibility to interactions with acids, bases, humidity, temperature and circulating ions. Several studies indicate that interaction with chloride (Cl−) ions can lead to the formation of degradation products, such as copper hydroxychlorides (Cu2Cl(OH)3), resulting in azurite acquiring greenish hues or black copper oxides (CuO) [61,62].
Although smalt provides a vibrant and durable color, it has been observed in some illuminations that it tends to discolor, probably due to potassium depletion and the incorporation of water molecules. In addition, it is important to mention that glaze has the disadvantage of being very unstable in oily media, as this results in darkening due to the formation of potassium soaps from the saponification reaction of the fatty acids in the oil [63] as observed in the illuminated San Francisco manuscripts where oil-bonded glaze was used.
The yellow and brown-ochre pigments, forms of iron oxides (Fe2O3), were found to be very stable. Their resistance to light and inertness in reactions with other pigments ensure that their color is maintained over time [61]. As for the gold leaves, in some cases they have detachments from the support, which is not due to a chemical reaction but to the result of their thickness and physical abrasion. Although no serious deterioration problems have been evidenced for indigo, it is important to consider that it also presents some vulnerabilities. Indigo can be sensitive to light, especially ultraviolet light. Prolonged exposure to intense light can cause discoloration of the pigment and loss of its original color [62]. In the case of cleaning or restoration processes, it should be considered that indigo is soluble in aqueous media, which means that it can dissolve in water. This can be a problem in humid environments or if the materials come into contact with water, which could cause color loss or damage.
As mentioned above, carmine is pH-sensitive and can take on different shades depending on the medium in which it is found [40], hence its vulnerability to environmental factors.
Saffron, sharing with indigo and carmine its organic nature, is also sensitive to light and may experience discoloration when exposed to ultraviolet light. Prolonged exposure to light and humidity may also affect color stability [64]. In the case of restoration processes, it should be considered that saffron is soluble in water, which means that its stability may be compromised in humid environments or contact with liquids.

4. Conclusions

The nondestructive IRFC technique enabled the identification of pigments and dyes in most of the manuscript illuminations when used in the pure state. In the case of mixtures, the IRFC did not provide conclusive results, but the nondestructive XRF technique achieved the precise identification of pigments, except for the green colors, for which both techniques could not differentiate between malachite and verdigris. In addition, it is important to consider that the analysis corresponds to a superficial type; therefore, it does not contribute to the knowledge of the chronology of the strata. To complement the information, the extraction of micro samples and the analysis by SEM-EDS and FT-IR allowed us to corroborate the exploratory results, acquire knowledge of the strata, and identify binders and green pigments.
From the information gathered through multi-analytical characterization, it was determined that the analyzed parchments show signs of a traditional production treatment. This method was based on the use of conventional materials such as lime (CaO) and sodium sulfite (Na2SO3) during their manufacturing process and surface treatment. As for the illuminations, they are a pictorial technique based on the traditional use of protein, polysaccharide and oil binders, applied together with the pigments and dyes on the support.
It was possible to determine the frequency of use of pigments and colorants in the illuminations. It was established that the pigments used most regularly in the illuminations were vermilion, minium, verdigris, orpiment, azurite, and indigo. The use of pigment mixtures was less common since they were identified only in some illuminations of the STD2 and SF2 books. The regular use of saffron was constant in the illuminations of the book STD2. Among the pigments used less regularly, yellow ochre was identified only in book STD2. The constant use of these materials allowed the illuminating artists to decorate the illuminations with a very varied chromatic palette.
Most of the pigments analyzed exhibit chemical stability; however, pigments such as vermilion, minium, orpiment and albayalde tend to blacken when exposed to air and light. As for azurite and malachite, they are stable pigments, but their contact with humidity and Cl− ions present in the medium can result in the formation of copper hydroxychlorides. Smalt is highly stable, although discoloration may occur due to the depletion of potassium and cobalt in its composition, and it tends to darken in oily media. Organic dyes, sensitive to light, may discolor with excessive exposure; carmine, in particular, is pH-sensitive, adopting various shades depending on the medium. Among the most stable are the ochers, which do not react with other pigments and maintain their stability against air and light.

Author Contributions

Conceptualization, M.R.-B., C.V.-M., K.G.-P. and F.E.-G.; methodology, K.G.-P., C.V.-M., J.R.-B.; formal analysis, L.R.-G., R.D.-B. and J.R-B; investigation, R.D.-B., K.G.-P., C.V.-M. and F.E.-G.; writing—original draft preparation, K.G.-P. and M.R.-B.; writing—review and editing, L.R.-G. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

No additional data are available.

Acknowledgments

The authors would like to thank the people responsible for the convents of San Agustín, San Francisco de Quito and Santo Domingo who facilitated access to the illuminated manuscripts, in situ analysis and sampling.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Bueno-Vargas, J. Deterioro En Encuadernaciones Manuscritas de Gran Formato: Causas Intrínsecas de Alteración En Los Libros de Coro. Cuad. Restaur. 2006, 6, 43–56. [Google Scholar]
  2. Gento, B. Historia de La Obra Constructiva de San Francisco Desde Su Fundación Hasta Nuestros Días, 1535–1942. 1942. Available online: https://repositorio.bne.gob.ec/xmlui/handle/34000/991 (accessed on 15 June 2024).
  3. Stevenson, R. Music in Quito: Four Centuries. Hisp. Am. Hist. Rev. 1963, 43, 247–266. [Google Scholar] [CrossRef]
  4. Webster, V.; Materiales, S. Modelos y Mercado de La Pintura En Quito, 1550–1650. Procesos. Rev. Ecuat. Hist. 2016, 43, 37–64. [Google Scholar] [CrossRef]
  5. López, G. Archivo y Biblioteca Nacionales de Bolivia. Unidad Documental Simple: 266v-267v—Poder Especial Que Otorga Tomé García. 2022. Available online: https://archivo-abnb.org.bo/index.php/poder-especial-que-otorga-tome-garcia-2 (accessed on 15 June 2024).
  6. González Suárez, F. Historia General de La República Del Ecuador; Imprenta del Clero: Quito, Ecuador, 1890. [Google Scholar]
  7. Navarro, J.G. La Pintura En El Ecuador Del XVI Al XIX; Dinediciones: Quito, Ecuador, 1991; pp. 52–59. ISBN 9978954058. [Google Scholar]
  8. Monagas, J.E. Documentación musical en el Convento de San Francisco deito: Libros litúrgico-musicales, órganos y coristas. Acta Musicol. 2021, 93, 43–66. [Google Scholar]
  9. Carvalho, I.; Casanova, C.; Araújo, R.; Lemos, A. Colour Identification, Degradation Processes and Findings in a Fifteenth-Century Book of Hours: The Case Study of Cofre n.o 31 from Mafra National Palace. Herit. Sci. 2018, 6, 9. [Google Scholar] [CrossRef]
  10. Bruni, S.; Caglio, S.; Guglielmi, V.; Poldi, G. The Joined Use of n.i. Spectroscopic Analyses—FTIR, Raman, Visible Reflectance Spectrometry and EDXRF—To Study Drawings and Illuminated Manuscripts. Appl. Phys. A Mater. Sci. Process. 2008, 92, 103–108. [Google Scholar] [CrossRef]
  11. Manso, M.; Le Gac, A.; Longelin, S.; Pessanha, S.; Frade, J.C.; Guerra, M.; Candeias, A.J.; Carvalho, M.L. Spectroscopic Characterization of a Masterpiece: The Manueline Foral Charter of Sintra. Spectrochim. Acta—Part A Mol. Biomol. Spectrosc. 2013, 105, 288–296. [Google Scholar] [CrossRef]
  12. Tanevska, V.; Nastova, I.; Minčeva-Šukarova, B.; Grupče, O.; Ozcatal, M.; Kavčić, M.; Jakovlevska-Spirovska, Z. Spectroscopic Analysis of Pigments and Inks in Manuscripts: II. Islamic Illuminated Manuscripts (16th–18th Century). Vib. Spectrosc. 2014, 73, 127–137. [Google Scholar] [CrossRef]
  13. Clarke, M. The Analysis of Medieval European Manuscripts. Stud. Conserv. 2001, 46, 3–17. [Google Scholar] [CrossRef]
  14. Poole, J.B.; Reed, R. The Preparation of Leather and Parchment by the Dead Sea Scrolls Community. Technol. Cult. 1962, 3, 1. [Google Scholar] [CrossRef]
  15. Sterflinger, K.; Pinzari, F. The Revenge of Time: Fungal Deterioration of Cultural Heritage with Particular Reference to Books, Paper and Parchment. Environ. Microbiol. 2012, 14, 559–566. [Google Scholar] [CrossRef] [PubMed]
  16. Badea, E.; Della Gatta, G.; Budrugeac, P. Characterisation and Evaluation of the Environmental Impact on Historical Parchments by Differential Scanning Calorimetry. J. Therm. Anal. Calorim. 2011, 104, 495–506. [Google Scholar] [CrossRef]
  17. Axelsson, K.M.; Larsen, R.; Sommer, D.V.P.; Melin, R. Degradation of Collagen in Parchment under the Influence of Heat-Induced Oxidation: Preliminary Study of Changes at Macroscopic, Microscopic, and Molecular Levels. Stud. Conserv. 2016, 61, 46–57. [Google Scholar] [CrossRef]
  18. Pozo-Antonio, J.S.; Jiménez-Desmond, D.; De Villalobos, L.; Mato, A.; Dionísio, A.; Rivas, T.; Cardell, C. SO2-Induced Aging of Hematite- and Cinnabar-Based Tempera Paint Mock-Ups: Influence of Binder Type/Pigment Size and Composition. Minerals 2023, 13, 289. [Google Scholar] [CrossRef]
  19. Castillejo, M.; Martín, M.; Oujja, M.; Santamaría, J.; Silva, D.; Torres, R.; Manousaki, A.; Zafiropulos, V.; Van Den Brink, O.F.; Heeren, R.M.A.; et al. Evaluation of the Chemical and Physical Changes Induced by KrF Laser Irradiation of Tempera Paints. J. Cult. Herit. 2003, 4, 257–263. [Google Scholar] [CrossRef]
  20. Troiano, F.; Polo, A.; Villa, F.; Cappitelli, F. Assessing the Microbiological Risk to Stored Sixteenth Century Parchment Manuscripts: A Holistic Approach Based on Molecular and Environmental Studies. Biofouling 2014, 30, 299–311. [Google Scholar] [CrossRef]
  21. Koochakzaei, A.; Bidgoli, B.J.; Safapour, S.; Nemati-Babaylo, A. Multispectral Imaging and Hyperspectral Techniques Applied to Dyed Fibers: A Classification Approach. Prog. Color Color. Coat. 2024, 17, 227–238. [Google Scholar] [CrossRef]
  22. Cosentino, A. Identification of Pigments by Multispectral Imaging; a Flowchart Method. Herit. Sci. 2014, 2, 8. [Google Scholar] [CrossRef]
  23. Dyer, J.; Verri, G.; Cupitt, J. Multispectral Imaging in Reflectance and Photo-Induced Luminescence Modes: A User Manual. 2013. Available online: https://www.researchgate.net/profile/Giovanni-Verri-2/publication/267266175_Multispectral_Imaging_in_Reflectance_and_Photo-induced_Luminescence_modes_A_User_Manual/links/5448e7560cf2d62c3052d2b7/Multispectral-Imaging-in-Reflectance-and-Photo-induced-Luminescence-modes-A-User-Manual.pdf (accessed on 15 June 2024).
  24. Lachmann, T.; van der Snickt, G.; Haschke, M.; Mantouvalou, I. Combined 1D, 2D and 3D Micro-XRF Techniques for the Analysis of Illuminated Manuscripts. J. Anal. At. Spectrom. 2016, 31, 1989–1997. [Google Scholar] [CrossRef]
  25. Hidalgo Brinquis, M. del C. Técnicas Medievales En La Elaboración Del Libro: Aportaciones Hispanas a La Fabricación Del Pergamino y Del Papel y a Los Sistemas de Encuadernación. Anu. Estud. Mediev. 2011, 41, 755–773. [Google Scholar] [CrossRef]
  26. Moreno González, M. Tratamiento de Los Pergaminos Utilizados En Los Libros de Coro de El Escorial. Signo Rev. Hist. Cult. Escrita 1997, 4, 169–176. [Google Scholar]
  27. Hagadorn, A. Parchment Making in Eighteenth-Century France: Historical Practices and the Written Record. J. Inst. Conserv. 2012, 35, 165–188. [Google Scholar] [CrossRef]
  28. Badea, E.; Miu, L.; Budrugeac, P.; Giurginca, M.; Mašić, A.; Badea, N.; Della Gatta, G. Study of Deterioration of Historical Parchments by Various Thermal Analysis Techniques Complemented by SEM, FTIR, UV-Vis-NIR and Unilateral NMR Investigations. J. Therm. Anal. Calorim. 2008, 91, 17–27. [Google Scholar] [CrossRef]
  29. Odlyha, M.; Theodorakopoulos, C.; Bozec, L. Fourier Transform Infra-Red Spectroscopy (ATR/FTIR) and Scanning Probe Microscopy of Parchment. e-Preserv. Sci. 2009, 6, 138–144. [Google Scholar]
  30. Boulc’h, F.; Bouillon, N.; Guillon, O.; Vallet, J.M.; Demoulin, A.; Gontero-Lauze, V. Painting Techniques of a 15th Century Illuminated Manuscript Revealed by Combining Multimodal Imaging Methods and X-Ray Fluorescence Spectroscopy. Available online: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=4404515 (accessed on 15 June 2024).
  31. Biolcati, V.; Wilson, M.; Fiddyment, S.; Unitt, R.; Ryan, C.C.; Hoffmann, A.G.; Gillis, J.; France, F.; Ó Macháin, P.; Iacopino, D. The Book of Uí Mhaine: An Interdisciplinary Analysis of the Materiality of the Gaelic Manuscript Tradition. Heritage 2023, 6, 5393–5409. [Google Scholar] [CrossRef]
  32. Koochakzaei, A.; Alizadeh Gharetapeh, S.; Jelodarian Bidgoli, B. Identification of Pigments Used in a Qajar Manuscript from Iran by Using Atomic and Molecular Spectroscopy and Technical Photography Methods. Herit. Sci. 2022, 10, 30. [Google Scholar] [CrossRef]
  33. Castañeda Delgado, M. Caracterización e Identificación Del Índigo Utilizado Como Pigmento En La Pintura de Caballete Novohispana. Bachelor’s Thesis, Escuela de Conservación y Restauración de Occidente, Guadalajara, Mexico, 2017. [Google Scholar]
  34. Seldes, A.M.; Burucúa, J.E.; Maier, M.S.; Abad, G.; Jáuregui, A.; Siracusano, G. Blue Pigments in South American Painting (1610–1780). J. Am. Inst. Conserv. 1999, 38, 100–123. [Google Scholar] [CrossRef]
  35. Parrilla Bou, M.A. El Arte de Los Pigmentos Análisis Histórico-Artístico de Su Evolución a Partir de Los Tratados Españoles de Francisco Pacheco y Antonio Palomino; Universitat de València, Servei de Publicacions: València, Spain, 2009; ISBN 9788437074436. [Google Scholar]
  36. Ordoudi, S.A.; De Los Mozos Pascual, M.; Tsimidou, M.Z. On the Quality Control of Traded Saffron by Means of Transmission Fourier-Transform Mid-Infrared (FT-MIR) Spectroscopy and Chemometrics. Food Chem. 2014, 150, 414–421. [Google Scholar] [CrossRef] [PubMed]
  37. Celis, F.; Segura, C.; Gómez-Jeria, J.S.; Campos-Vallette, M.; Sanchez-Cortes, S. Analysis of Biomolecules in Cochineal Dyed Archaeological Textiles by Surface-Enhanced Raman Spectroscopy. Sci. Rep. 2021, 11, 6560. [Google Scholar] [CrossRef]
  38. Kannangara, R.; Siukstaite, L.; Borch-Jensen, J.; Madsen, B.; Kongstad, K.T.; Staerk, D.; Bennedsen, M.; Okkels, F.T.; Rasmussen, S.A.; Larsen, T.O.; et al. Characterization of a Membrane-Bound C-Glucosyltransferase Responsible for Carminic Acid Biosynthesis in Dactylopius Coccus Costa. Nat. Commun. 2017, 8, 1987. [Google Scholar] [CrossRef]
  39. Kroustallis, S. Binding Media in Medieval Manuscript Illumination: A Source Research. Rev. História da Arte 2011, 1, 112–125. [Google Scholar]
  40. Valipour, P.; Ekrami, E.; Shams Nateri, A. Colorimetric Properties of Wool Dyed with Cochineal: Effect of Dye-Bath PH. Prog. Color Color. Coat. 2013, 7, 129–138. [Google Scholar] [CrossRef]
  41. Kroustallis, S. Quomodo Decoretur Pictura Librorum: Materiales y Técnicas de La Iluminación Medieval. Anu. Estud. Mediev. 2011, 41, 775–802. [Google Scholar] [CrossRef]
  42. Castellanos Rodriguez, D.M. Desarrollo de Metodologías Analíticas Basadas En Espectrometría de Masa y Espectroscopía Infrarroja Para La Identificación de Aglutinantes Orgánicos y Sus Productos de Degradación En Arte Colonial. 2018. Available online: http://hdl.handle.net/11336/83588 (accessed on 18 May 2024).
  43. Pacheco, F. Arte de La Pintura, Su Antigüedad y Grandezas; Biblioteca Virtual Miguel de Cervantes: Alicante, Spain, 1871. [Google Scholar]
  44. Bruquetas, R. The Search for the Perfect Color: Pigments, Tints, and Binders in the Scientific Expeditions to the Americas. J. Interdiscip. Hist. 2015, 45, 367–387. [Google Scholar] [CrossRef]
  45. Larsen, R.; Vest, M.; Kejser, U.B. STEP Leather Project: Evaluation of the Correlation between Natural and Artificial Ageing of Vegetable Tanned Leather and Determination of Parameters for Standardization of an Artificial Ageing Method. 1994. Available online: https://archive.org/details/stepleatherproje0000step/page/n6/mode/1up (accessed on 22 July 2024).
  46. Sharma, J.; Bohidar, H.B. Gelatin-Glutaraldehyde Supramolecular Structures Studied by Laser Light Scattering. Eur. Polym. J. 2000, 36, 1409–1418. [Google Scholar] [CrossRef]
  47. Kennedy, C.J.; Hiller, J.; Odlyha, M.; Nielsen, K.; Drakopoulos, M.; Wess, T.J. Degradation in Historical Parchments: Structural, Biochemical, and Thermal Studies TT—Paper Restoration. Pap. Mitteilungen IADA 2002, 3, 23–30. [Google Scholar]
  48. Hansen, E.F.; Lee, S.N.; Sobel, H. The Effects of Relative Humidity on Some Physical Properties of Modern Vellum: Implications for the Optimum Relative Humidity for the Display and Storage of Parchment. J. Am. Inst. Conserv. 1992, 31, 325–342. [Google Scholar] [CrossRef]
  49. BS 4971:2017; Conservation and Care of Archive and Library Collections. British Standards Institution: London, UK, 2017. Available online: https://knowledge.bsigroup.com/products/conservation-and-care-of-archive-and-library-collections?version=standard (accessed on 22 July 2024).
  50. ISO 11799:2024; Information and Documentation—Document Storage Requirements for Archive and Library Materials. International Organization for Standardization: Geneva, Switzerland, 2024. Available online: https://www.iso.org/es/contents/data/standard/08/23/82306.html (accessed on 2 July 2024).
  51. Ma, Z.; Yang, L.; Wang, L.; Pitthard, V.; Bayerova, T.; Krist, G.; Zhao, X. The Influence of Natural Aging Exerting on the Stability of Some Proteinaceous Binding Media Commonly Used in Painted Artworks. Coatings 2022, 12, 1522. [Google Scholar] [CrossRef]
  52. Špec, T.; Retko, K.; Ropret, P.; Meden, A.; Bernard, J. The Influence of UV-Vis Radiation, and Oscillations of Temperature and Relative Humidity, on Malachite Alteration in the Presence of Different Organic Binders and Varnishes. J. Raman Spectrosc. 2014, 45, 1068–1075. [Google Scholar] [CrossRef]
  53. Spring, M.; Grout, R. The Blackening of Vermilion: An Analytical Study of the Process in Paintings. Natl. Gall. Tech. Bull. 2002, 23, 50–61. [Google Scholar]
  54. Mccormack, J.K. LETTE R The Darkening of Cinnabar in Sunlight. Miner. Depos. 2000, 35, 796–798. [Google Scholar] [CrossRef]
  55. Da Pieve, F.; Hogan, C.; Lamoen, D.; Verbeeck, J.; Vanmeert, F.; Radepont, M.; Cotte, M.; Janssens, K.; Gonze, X.; Van Tendeloo, G. Casting Light on the Darkening of Colors in Historical Paintings. Phys. Rev. Lett. 2013, 111, 208302. [Google Scholar] [CrossRef] [PubMed]
  56. Hogan, C.; Da Pieve, F. Colour Degradation of Artworks: An Ab Initio Approach to X-Ray, Electronic and Optical Spectroscopy Analyses of Vermilion Photodarkening. J. Anal. At. Spectrom. 2015, 30, 588–598. [Google Scholar] [CrossRef]
  57. Anaf, W.; Janssens, K.; De Wael, K. Formation of Metallic Mercury During Photodegradation/Photodarkening of A-HgS: Electrochemical Evidence. Angew. Chem. 2013, 125, 12800–12803. [Google Scholar] [CrossRef]
  58. Davidson, R.S.; Willsher, C.J. The Light-Induced Blackening of Red Mercury(II) Sulphide. J. Chem. Soc. Dalton Trans. 1981, 3, 833–835. [Google Scholar] [CrossRef]
  59. Radepont, M.; Coquinot, Y.; Janssens, K.; Ezrati, J.J.; De Nolf, W.; Cotte, M. Thermodynamic and Experimental Study of the Degradation of the Red Pigment Mercury Sulfide. J. Anal. At. Spectrom. 2015, 30, 599–612. [Google Scholar] [CrossRef]
  60. Elert, K.; Cardell, C. Weathering Behavior of Cinnabar-Based Tempera Paints upon Natural and Accelerated Aging. Spectrochim. Acta—Part A Mol. Biomol. Spectrosc. 2019, 216, 236–248. [Google Scholar] [CrossRef]
  61. Coccato, A.; Moens, L.; Vandenabeele, P. On the Stability of Mediaeval Inorganic Pigments: A Literature Review of the Effect of Climate, Material Selection, Biological Activity, Analysis and Conservation Treatments. Herit. Sci. 2017, 5, 12. [Google Scholar] [CrossRef]
  62. Lluveras, A.; Boularand, S.; Andreotti, A.; Vendrell-Saz, M. Degradation of Azurite in Mural Paintings: Distribution of Copper Carbonate, Chlorides and Oxalates by SRFTIR. Appl. Phys. A Mater. Sci. Process. 2010, 99, 363–375. [Google Scholar] [CrossRef]
  63. van Loon, A.; Noble, P.; de Man, D.; Alfeld, M.; Callewaert, T.; Van der Snickt, G.; Janssens, K.; Dik, J. The Role of Smalt in Complex Pigment Mixtures in Rembrandt’s Homer 1663: Combining MA-XRF Imaging, Microanalysis, Paint Reconstructions and OCT. Herit. Sci. 2020, 8, 90. [Google Scholar] [CrossRef]
  64. Vickackaite, V.; Romani, A.; Pannacci, D.; Favaro, G. Photochemical and Thermal Degradation of a Naturally Occurring Dye Used in Artistic Painting. A Chromatographic, Spectrophotometric and Fluorimetric Study on Saffron. Int. J. Photoenergy 2004, 6, 175–183. [Google Scholar] [CrossRef]
Heritage 07 00305 g001
Figure 1. Diagram of the multi-analytical methodology for the characterization of illuminated choirbooks.
Figure 1. Diagram of the multi-analytical methodology for the characterization of illuminated choirbooks.
Heritage 07 00305 g001
Heritage 07 00305 g002
Figure 2. IRFC images. (a) Exchange of RGB channels to create the IRFC image, (b,c) VIS and IRFC images of reference pigments. R = red, G = green, B = blue.
Figure 2. IRFC images. (a) Exchange of RGB channels to create the IRFC image, (b,c) VIS and IRFC images of reference pigments. R = red, G = green, B = blue.
Heritage 07 00305 g002
Heritage 07 00305 g003
Figure 3. FTIR-ATR LC-STD2 analysis of collagen (black line) and STD2 sample (dark yellow line).
Figure 3. FTIR-ATR LC-STD2 analysis of collagen (black line) and STD2 sample (dark yellow line).
Heritage 07 00305 g003
Heritage 07 00305 g004
Figure 4. Analysis of red and orange illuminations: (a) visible light, (b) IRFC, (c) MO micrograph and (d) chemical mapping. Circles are enlargement of small sections of the illuminations.
Figure 4. Analysis of red and orange illuminations: (a) visible light, (b) IRFC, (c) MO micrograph and (d) chemical mapping. Circles are enlargement of small sections of the illuminations.
Heritage 07 00305 g004
Heritage 07 00305 g005
Figure 5. IRFC analysis of the blue illuminations. (a) Indigo STD1. (b) Azurite STD2. (c) Unidentified SF2. Circles are enlargement of small sections of the illuminations.
Figure 5. IRFC analysis of the blue illuminations. (a) Indigo STD1. (b) Azurite STD2. (c) Unidentified SF2. Circles are enlargement of small sections of the illuminations.
Heritage 07 00305 g005
Heritage 07 00305 g006
Figure 6. Microchemical analysis of blue illuminations: (a) XRF spectrum of azurite in STD2, (b) XRF spectrum of smalt in SF2 and (c) FTIR-ATR spectrum of indigo in STD1.
Figure 6. Microchemical analysis of blue illuminations: (a) XRF spectrum of azurite in STD2, (b) XRF spectrum of smalt in SF2 and (c) FTIR-ATR spectrum of indigo in STD1.
Heritage 07 00305 g006
Heritage 07 00305 g007
Figure 7. IRFC analysis of the green illuminations. (a,b) Verdigris in STD1 and STD2. (c) Unidentified in SF2. Circles are enlargement of small sections of the illuminations.
Figure 7. IRFC analysis of the green illuminations. (a,b) Verdigris in STD1 and STD2. (c) Unidentified in SF2. Circles are enlargement of small sections of the illuminations.
Heritage 07 00305 g007
Heritage 07 00305 g008
Figure 8. Chemical analysis of green SF2 illuminations. (a) Sampling site; (b) MO micrograph; (c) SEM micrograph; (d) EDX spectrum; (e,f) EDX mapping.
Figure 8. Chemical analysis of green SF2 illuminations. (a) Sampling site; (b) MO micrograph; (c) SEM micrograph; (d) EDX spectrum; (e,f) EDX mapping.
Heritage 07 00305 g008
Heritage 07 00305 g009
Figure 9. Chemical analysis of yellow STD2 illuminations. (a) Sampling site; (b) MO micrograph; (c,d); EDX mapping; (e) FTIR-ATR spectra.
Figure 9. Chemical analysis of yellow STD2 illuminations. (a) Sampling site; (b) MO micrograph; (c,d); EDX mapping; (e) FTIR-ATR spectra.
Heritage 07 00305 g009
Heritage 07 00305 g010
Figure 10. Microchemical analysis of STD1 violet illuminations. (a,b) VIS and IRFC images of carmine; (c) FT-IR spectrum of a carmine sample. Circles are enlargement of small sections of the illuminations.
Figure 10. Microchemical analysis of STD1 violet illuminations. (a,b) VIS and IRFC images of carmine; (c) FT-IR spectrum of a carmine sample. Circles are enlargement of small sections of the illuminations.
Heritage 07 00305 g010
Heritage 07 00305 g011
Figure 11. Microchemical analysis of SF1 gold illumination. (a) Sampling site. (b) Micrograph polished section. (c) SEM-RDS chemical mapping.
Figure 11. Microchemical analysis of SF1 gold illumination. (a) Sampling site. (b) Micrograph polished section. (c) SEM-RDS chemical mapping.
Heritage 07 00305 g011
Table 1. XVII century illuminated manuscripts from Royal Society of Quito under study.
Table 1. XVII century illuminated manuscripts from Royal Society of Quito under study.
Illuminated ManuscriptsRepositoryAuthorTemporalityFeatured Image
STD1Book of PsalmsSanto Domingo ConventAnonymousS. XVIIHeritage 07 00305 i001
SF1Illuminated manuscript of Apostle CommonsSan Francisco ConventAnonymousS. XVIIHeritage 07 00305 i002
STD2Illuminated manuscript SNSanto Domingo ConventAttributed to Fray Pedro Bedón1613Heritage 07 00305 i003
SF2Book of psalmsSan Francisco ConventAnonymousS. XVIIHeritage 07 00305 i004
SA1St. Augustine’s Festivities ChoirbookSan Agustin ConventFriar Francisco de la Fuente1628Heritage 07 00305 i005
Table 2. Summary of results of instrumental analysis performed.
Table 2. Summary of results of instrumental analysis performed.
Analyzed
Area		ChoirbookIRFCChemical Elements (XRF)FTIR Bands (cm−1)Interpretation
ParchmentSTD1
SF1
STD2
SF2
SA1		 Ca (33%), S (7%), Al, Si, Cl, K, Fe
Ca (38%), S (11%), Al, Si, Cl, K, Fe
Ca (45%), S (8%), Al, Si, Cl, K, Fe
Ca (50%), S (7%), Al, Si, Cl, K, Fe
Ca (42%), S (8%), Al, Si, Cl, K, Fe		2900–2800, 1000–1250, 1650–1500, 1234Use of calcium hydroxide, sodium sulfite, poem stone and salts in the parchment production process Gelatinization processes
Yellow colorSF1, STD1, SA1-As, S, (Si, Al, K, Ca) Orpiment
SF2-As, Pb, S, Si (Al, K, Fe) Orpiment, masicot
STD2-Fe, Si, Al (Na, K, Mg, Ca, S)3355, 2923, 2853,1710, 1745, 1643, 1015Yellow ochre, saffron
Orange colorSTD1, STD2, SA1Light yellowPb (Al, Si, K, Fe, Ca) Minium
STD2, SF2, SA1Dark yellowPb, Hg, S (Al, Si, K, Ca) Minium, Vermilion
SA1-Pb (Al, Si, K, Fe, Ca)-Minium
Golden colorSF1, STD2, SF2-Au, Cu-Gold leaf
Blue color SF1, STD2BrownCu (Mg, Al, Si, Ca, Fe)-Azurite
SA1BrownCu, Pb (Mg, Al, Si, Ca, Fe) Azurite, lead white
SF1, SF2-Co, Ni, As, Si, K (Al, Ca, Fe)-Smalt
STD1, SF1, STD2Bright red 1670, 1461Indigo
Red colorSF1, STD2, SF2Dark yellowHg, S (Al, Si, K, Ca) Vermilion
Green colorSTD1, SA1BlueCu, Si, P (Ca, Al, S) Verdigris
STD2BlueCu, Ca, Si, (Al, Si, P) Verdigris, lime white
SF1BlueCu, Si, P (Al, Si, Ca) Malachite/Verdigris, bone black
SF2BlueCu, Si, C (Al, Si,) Malachite/Verdigris, black with humus
VioletSTD2, SF2Light coffeePb (Si, K, Ca)1628, 1454, 1418, 1240, 1033Carmine, Minium
Table 3. Summary of identified pictorial materials.
Table 3. Summary of identified pictorial materials.
Pigments and DyesChoirbooks
STD1SF1STD2SF2SA1
BlueIndigoIndigo
Azurite
Smalt		Azurite
Indigo		SmaltAzurite + lead white
GreenVerdigrisMalachite/Verdigris
Verdigris +
Bone black		Verdigris + Lime whiteMalachite/Verdigris + Carbon blackVerdigris
YellowOrpimentOrpimentSaffron
Yellow Ochre		Orpiment
Masicot		Orpiment
Gilding Gold leafGold leafGold leaf
RedVermilionVermilionVermilionVermilionVermilion
OrangeMinium Minium
Vermilion + Minium		Vermilion + MiniumMinium
VioletsCarmineCarmineCarmine + MiniumCarmine
Carmine + Minium		Carmine
BindersEgg yolk and white + oilOilArabic gumOilEgg yolk and white + oil,
gum arabic
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Romero-Bastidas, M.; Guacho-Pachacama, K.; Vásquez-Mora, C.; Espinoza-Guerra, F.; Díaz-Benalcázar, R.; Ramírez-Bustamante, J.; Ramos-Guerrero, L. Multi-Analytical Characterization of Illuminated Choirbooks from the Royal Audience of Quito. Heritage 2024, 7, 6592-6613. https://doi.org/10.3390/heritage7120305

AMA Style

Romero-Bastidas M, Guacho-Pachacama K, Vásquez-Mora C, Espinoza-Guerra F, Díaz-Benalcázar R, Ramírez-Bustamante J, Ramos-Guerrero L. Multi-Analytical Characterization of Illuminated Choirbooks from the Royal Audience of Quito. Heritage. 2024; 7(12):6592-6613. https://doi.org/10.3390/heritage7120305

Chicago/Turabian Style

Romero-Bastidas, Martha, Katherine Guacho-Pachacama, Carlos Vásquez-Mora, Fernando Espinoza-Guerra, Rita Díaz-Benalcázar, Johanna Ramírez-Bustamante, and Luis Ramos-Guerrero. 2024. "Multi-Analytical Characterization of Illuminated Choirbooks from the Royal Audience of Quito" Heritage 7, no. 12: 6592-6613. https://doi.org/10.3390/heritage7120305

APA Style

Romero-Bastidas, M., Guacho-Pachacama, K., Vásquez-Mora, C., Espinoza-Guerra, F., Díaz-Benalcázar, R., Ramírez-Bustamante, J., & Ramos-Guerrero, L. (2024). Multi-Analytical Characterization of Illuminated Choirbooks from the Royal Audience of Quito. Heritage, 7(12), 6592-6613. https://doi.org/10.3390/heritage7120305

Article Metrics

Back to TopTop