**1. Introduction**

The identification of the palette is among the various tasks of the scientific examination of an illuminated manuscript. Techniques and materials for illumination are reported, in principle, in some ancient manuals [1,2] which sometimes use colloquial names which may not be reliable descriptors of the substances actually employed. The combined contribution of researchers from the fields of natural sciences and humanities has shed light on this topic and now the set of the most relevant inorganic colourants employed in illumination is known [1–5]. Nevertheless, the materials used to decorate a specific codex may not be accurately recognised even by an expert eye, since different colourants may yield similar hues, they can be mixed to obtain a particular colour or applied in multilayers and the original colour can be modified and obscured by weathering [6,7]. Therefore, instrumental investigation still plays a crucial role in the recognition of the materials that were actually employed.

The characterisation of the palette gives useful information for conservation and also aids the selection of the proper conditions for preserving or exhibiting these fragile

**Citation:** Agostino, A.; Pellizzi, E.; Aceto, M.; Castronovo, S.; Saroni, G.; Gulmini, M. On the Hierarchical Use of Colourants in a 15th Century *Book of Hours*. *Heritage* **2021**, *4*, 1786–1806. https://doi.org/10.3390/heritage4030100

Academic Editor: Lucia Burgio

Received: 16 July 2021 Accepted: 11 August 2021 Published: 13 August 2021

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**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

artworks. The determination of the original colourants within a manuscript may confirm or reject its authenticity [8] or may suggest a date for its production, since the period in which different colourants were in use is known. Moreover, a particular set of colourants, along with the compositions of the material employed, may lead to the identification of scriptoria and workshops or to the recognition of the intervention of different hands upon a series of codices or within a single manuscript. More generally, the knowledge of the materials employed expands the information available on a specific book, on the artists who decorated it and on the institutional or private clients for which the book was produced [9–12].

The choice of colourants used to decorate the various features is of particular interest to art historians: precious pigments may be chosen for the most important details, while more conventional materials might be used for less important details [1]. A hierarchy of colourants, following the market values of the materials, can reveal the schemes pursued by the artist in the representation of the various features. A commodity-related evaluation of the colourants used in a manuscript can be highly informative about its intrinsic value. These aspects usually receive very little attention in art historical studies.

With the aim of highlighting this specific topic, in this work we identified the colourants and evaluated the overall palette employed on a 15th century *Book of Hours* (in use in Chalon-sur-Saône) finely illuminated by the Burgundian painter Antoine de Lonhy.

Lonhy was a fascinating figure who was an itinerant artist active from circa 1446 to 1490 in Burgundy, Languedoc, Catalonia and in the Duchy of Savoy. His activity is presently documented by a large variety of artworks, including paintings on wood, frescoes, miniatures, cartoons for stained glass and embroidery [13–15]. A *Book of Hours* was a Christian devotional book with prayers to be said at certain times throughout the day. The small (17.2 × 11.7 cm) book investigated in this work consists of eighty-one pages of vellum with ten large arch-topped miniatures (Table 1) and decorated initials.


**Table 1.** The subjects of the miniatures.

A rich naturalistic decoration, with acanthus, fruits and flowers, borders each page (Figure 1a).

The manuscript was made approximately between 1446 and 1449 in Burgundy, during the initial period of Lonhy's activity, but besides this, very little information was available about the manuscript until 1966, when it appeared in the catalogue of an auction house. A description of what is known about the book and its history, as well as an exhaustive review of the publications dealing with the versatile activity of Antoine de Lonhy has been produced by Saroni [16]. The manuscript has been owned by the Museo Civico di Arte Antica—MCAA—in Torino (Italy) since 2002 and it is currently displayed in the prestigious Palazzo Madama, home of MCAA, with the signature Inv. n. 399. The museum's collection includes some other artworks of the artist, who is strongly linked to Torino itself and to the

surrounding region (Piedmont). The book is in fact an important element for documenting the figure of Antoine de Lonhy in his early years of activity.

**Figure 1.** (**a**) f. 1r, *Annunciation*. The main characteristics of the book (illuminated capital letters, rich four-side naturalistic decorations, arch topped miniatures) are shown. (**b**) f. 15r, *Visitation*. (**c**) f. 24r, *Nativity*. (**d**) f. 28v, *Angel announcing the Nativity to the shepherds*. (**e**) f. 31v, *Adoration of the Magi*. (**f**) f. 36v, *Holy Family in the run to Egypt*. (**g**) f. 42r, *God the Father and Jesus crowning the Virgin*. (**h**) f. 46r, *Crucifixion*, with the Virgin and St. John the Evangelist. (**i**) f. 49v, *Pentecost*. (**j**) f. 71v, *Burial service*.

Evidence of some conservation treatments and inpainting are present, although the exact extension and the date of these treatments are unknown: the original bookbinding was removed, the cover was substituted and some parts are missing whereas some pages have been added. Additionally, the sequence of the devotional texts has probably been modified. Rough retouches are evident on three miniatures and the presence of other, less evident, interventions in the upper part of most of the other miniatures was suggested by experts who examined the manuscript before its acquisition by the Museum.

As requested by the curator of the Museum's collection, non-invasive techniques were selected for investigating the colourants: optical microscopy (OM), fibre optic reflectance spectroscopy (FORS), fibre optic molecular fluorimetry (FOMF), X-ray fluorescence spectrometry (XRF) and micro-Raman spectroscopy (micro-Raman). Portable instrumentations were used in order to keep the precious manuscript in the Museum during the scientific investigation. Apart from identifying the original colourants, the investigation was extended to some evident retouches in order to suggest a possible date for the interventions on the miniatures.

The results from these analyses show that the palette used by the artist was rich and variegated and it is therefore a perfect candidate to testify how painters of manuscripts exploited different colourants to express their art in the 15th century, with intrinsic meaning beyond the mere colour.
