Extant medieval illuminated Hebrew manuscripts are complex material objects and a distinct group of heritage artefacts which contain some features that are uncharacteristic of Latin manuscripts produced in the same era. The rate of literacy among medieval Jews was very high and, due the need for personal copies of religious texts, lay individuals often copied their own manuscripts [1, 2]. In addition, migrations of medieval Jewish individuals and communities means that Hebrew manuscripts made in geographically disparate locations sometimes exhibit common codicological and palaeographical characteristics, as well as similarities in the artwork [1, 2]. Along with the frequent absence of specific identifying information concerning the circumstances of production, this means that questions about their origins and past history cannot easily be resolved for many manuscripts.Footnote 1 In the case of illuminated Hebrew manuscripts made in late medieval Europe, this challenge can be compounded by uncertainty surrounding the identities of the artists, and whether they were Jews or Christians [7,8,9,10,11].
We know that there were Jewish artists active during the later medieval period, but there is little solid evidence as only a few of these are known by name [12, 13]. One of the only surviving medieval treatises on paint recipes for book illumination is contained in a 15th-century manuscript that is in Portuguese but transliterated into Hebrew characters by a Jewish scribe, Abraham ben Judah ibn Hayyim, which suggests that this treatise was intended for a Jewish readershipFootnote 2 [14,15,16,17,18,19]. Yet whereas there are many scribal colophons, artists’ colophons or other information identifying those who decorated Hebrew manuscripts are rareFootnote 3 [12, 13]. A number of scholars have convincingly argued that Jews and Christians interacted in the making of illuminated manuscripts and cooperated in manuscript production [1, 6, 8, 13]. We know there were Christian secular workshops in the late Middle Ages who participated in creating the artwork for some illuminated Hebrew manuscriptsFootnote 4 [8, 11, 20, 21], and a wide range of motifs can be seen in both Hebrew and Latin manuscript illuminations, making it clear that they shared a common repertoire of artists’ models [7,8,9, 22,23,24,25].
However, questions about artwork authorship in Hebrew manuscripts arise in interpreting illustrations which show the undeniable influence of Christian iconography but appear alongside Jewish texts, especially images which had strongly religious connotations when appearing in a Christian context [7,8,9, 24,25,26,27]. If Christian artists were involved in creating the images in a Hebrew manuscript on commission by a Jewish patron or scribe, to what extent do such images introduce a Christian viewpoint, consciously or unconsciously, into a Jewish book [7,8,9,10]? Conversely, if Jewish artists used models well-known in Christian artworks, do such images reflect or reinterpret the meanings as understood by Christians when intended for a Jewish audience [24, 25, 28]? These are long-standing issues that have been the focus of art historical studies of illuminated Hebrew manuscripts for over a century [28, 29]. Gaining greater understanding about the techniques, production processes and materials used by the artists of Hebrew manuscripts can add new information to consideration of these questions.
Relatively little is known about the working methods of Jewish illuminators, since they were excluded from membership in medieval craft guilds which were often Christian confraternities [30]. It is thus unlikely that Jewish artists were employed or trained as apprentices by Christian illuminators’ workshops. We are uncertain if they usually worked alone, or if there were multiple artists working together, or if they had systematic methods of work which paralleled those seen in the work of Christian illuminators. A great deal is known about the technical production of illuminations in Latin manuscripts, but despite the fact that Hebrew illuminated manuscript production occurred in parallel with Latin manuscripts in the late Middle Ages, to date mainstream discussions about medieval illumination practices have largely neglected Hebrew manuscriptsFootnote 5 [31]. Studies in Hebrew codicology make it clear that the creators of Hebrew and Latin illuminated manuscripts shared some technical aspects of production [1, 2]. Indeed, ibn Hayyim’s treatise on paint recipes is a transliteration of the Portuguese vernacular and, while we don’t know if he made it for his own use or that of others, its contents imply it was made for practical useFootnote 6 [14, 19]. But more evidence is needed about the technical aspects of artistic production to piece together a clearer picture of the methods used by medieval Jewish artists in the decoration and painting of their books.
Non-invasive scientific imaging techniques have been successfully applied to investigate the materials and production of medieval artefacts, including manuscripts [33,34,35]; however, few of these have focussed on medieval Hebrew manuscripts [36,39,38], and fewer still on illuminated Hebrew manuscripts [39–41]Footnote 7. Scientific imaging analysis of illuminated Hebrew manuscripts, such as pigment identification, can contribute valuable information about how they were made. For example, analysis of the Jewish Theological Seminary Library’s unfinished Prato Haggadah using X-ray Fluorescence (XRF) and Raman spectroscopy, carried out by Stavisky et al. [41], showed that the composition of pigments in this manuscript are consonant with descriptions in medieval paint treatises, including that of ibn Hayyim [14, 18], and allowed insight into other aspects of the planning process and methods used in making it. However, since the Prato Haggadah lacks a scribal colophon, and it is not clear whether the artwork was partially executed by one or more Jewish artists or by a Christian workshop on commission, its provenance is still a mystery.Footnote 8
The Oppenheimer Siddur (Oxford Bodleian Library MS Opp. 776) has unique features which make it an ideal case study for the application of scientific imaging techniques in order to investigate artwork authorship in a Hebrew manuscript.Footnote 9 It is a richly illuminated, small-format, 15th-century Hebrew book of daily prayers according to the Ashkenazic rite of the Rhine region (Fig. 1). Information in the scribal colophon tells us that Asher ben Yitzḥaq finished copying the prayer book in 1471 for his family to use and therefore is classified as user-produced.Footnote 10 The scribe’s hand appears in neat, semi-cursive Ashkenazic script throughout this small-format manuscript, written on fine parchment that has been scraped on both sides to achieve an equalised texture, a technique used in Hebrew manuscripts only in Germany after c.1300 [43]. Despite the visually attractive qualities in the scribal work and illuminations, the self-made character of this manuscript is evident in the numerous copying mistakes and corrections made by the scribe, which would not be expected in the work of a professional copyist.Footnote 11 The frequent appearance of performing musicians in the iconography of this prayer book is a distinctive feature, one that is both thematic and symbolic in relation to the prayers it contains [44]. In addition, there are high quality illustrations of flora and fauna, wild men, a wide range of colours, and evidence of liberal application of gold in the illumination process, much of which has flaked off over time. It is clear from the contextualisation of the elements in the iconography that the illuminator had access to artists’ models that were in circulation in the 15th century, and was aware of the connotations as well as the forms of motifs adapted from contemporary Christian visual cultures [45, 46]. The amount and quality of artwork, combined with its documented user-produced provenance, make the Oppenheimer Siddur a rarity among extant Hebrew manuscripts. Yet although we know that Asher ben Yitzḥaq copied his own prayer book, the colophon does not confirm his identity as the artist.
Numerous illuminated Hebrew manuscripts display a sequential production process, in which figural illustrations and painted miniatures have been added after all scribal work was finished. This is obvious in some manuscripts where layout and texts have been planned and copied, but blank space has been left for the addition of drawings and illuminations that were not finished, or pigments in the painting process have been only partially applied to existing drawings.Footnote 12 In such cases, it is clear that copying of main texts and decoration, including the execution of drawings, occurred at separate stages of production. In the case of the Oppenheimer Siddur, all elements of text copying and artwork were fully completed. However, examination of different points in the manuscript using high-resolution (20 μm per pixel resolution) digital colour images revealed points of contact between the decorative coloured pigments and ink used at some points in the texts, as well as between the pigments of texts and those of illuminations, in an apparently inconsistent pattern of overlapping pigments (Fig. 2a–c). In addition, previous analysis of the manuscript showed that both scribal work and painted illuminations at times use stylistically similar ornamental decorative flourishes and floret motifs (Fig. 1b), as well as a similar colour palette (Fig. 2d) [45].
These aspects of the manuscript raised questions about the sequence of scribal copying relative to the execution of artwork, and suggested the hypothesis that the scribe may also have been the artist [45]. If a sequential production process were exhibited, with the copying of main texts preceding the addition of underdrawings and painted illuminations, it is probable that the artwork could have been done by someone other than the scribe. Conversely, if it were established that the copying, drawing and painting stages of the manuscript were done concurrently, and using the same pigments in both text copying and artwork, this could provide evidence that the artwork was executed by Asher ben Yitzḥaq. The Oppenheimer Siddur is very smallFootnote 13 and high resolution digital images alone proved insufficient to resolve these questions. Non-invasive scientific imaging techniques were sought to help clarify the sequence of production, and provide information about whether the same pigments were used in both scribal copying and painted illuminations, and to try to evaluate the implications of overlapping pigments between scribal work and painted artwork. This paper will show how spectral imaging and Fourier transform infrared spectroscopy in the attenuated total reflection mode (FTIR-ATR) were used to analyse the production sequence and pigments in the Oppenheimer Siddur in order to resolve questions regarding the artwork authorship for this Hebrew manuscript, and elucidate aspects of the production methods used in making it.