Study of Works on Parchment

J. Paul Getty Museum Laudario Leaves

In order to begin to address the question of whether material analysis could distinguish the hand of Pacino di Bonaguida from that of his collaborator, the Master of the Dominican Effigies, the three leaves from the Laudario of Sant'Agnese in the collection of the J. Paul Getty Museum were subjected to in-depth study. Using only noninvasive analytical techniques, GCI scientists carefully characterized the pigments used to paint each illumination. X-ray fluorescence (XRF) spectroscopy, Raman spectroscopy, and multispectral imaging provided a measure of the chemical elements and molecular composition in examined areas, as well as the likely distribution of pigments across the illuminations.
Analysis of The Ascension of Christ (JPGM, Ms. 8oa, verso) by Pacino di Bonaguida. Left: XRF analysis; Middle: multispectral imaging; Right: visual representation of the red pigments/colorants likely used. Photos: K. Trentelman, C. Patterson. Image: J. Paul Getty Museum.
From these initial studies, a picture began to emerge of the pigment palette used to create each illumination. Perhaps not surprisingly, the results suggested the two artists employed very similar palettes, consisting of common fourteenth-century pigments, such as vermilion, red lead, azurite, and ultramarine. By focusing over an extended period of time on works in the Getty's collection, researchers were able to develop an analytical protocol, refine the questions being addressed, and build a foundation for additional studies.

The Fitzwilliam Museum and Queens' College Laudario Leaves
X-rays of leaves of the Laudario of Sant'Agnese
The Laudario of Sant'Agnese was broken up in the early nineteenth century. Some of the leaves survive intact, but in some cases the miniatures were cut from the full leaves, and the fragments scattered to public and private collections around the world. In 2009 Stella Panayotova of the Fitzwilliam Museum published an article describing the rediscovery of four miniatures from the Laudario at Queens' College and the Fitzwilliam Museum, bringing the total number of extant fragments to twenty-eight.

Queens' College and the Fitzwilliam Museum agreed to bring these newly discovered miniatures, together with two additional leaves in the collection of the Fitzwilliam Museum, to the Getty for inclusion in this study. Using the same noninvasive analyses as were used on the three Getty Laudario leaves, the pigments and colorants used to create the illustrations were examined, further building a database of the materials and application methods employed by Pacino and his workshop.
The reverse sides of several of the Cambridge leaves, where the folio number would have been written, were obscured by the remnants of paper backings. X-radiography—a technique more commonly employed for the study of paintings than manuscript illuminations—was used to reveal the foliation, which helped confirm and revise curatorial understanding of the original order of the leaves. Interestingly, the radiographs also yielded information about the painting techniques used to create the miniatures, which could then be compared to Pacino's work on panel.
x-ray detail

Works on Parchment in Other Collections

To further extend the scope of the study, leaves or fragments from the Laudario and other manuscripts illustrated by Pacino, his collaborators, and his contemporaries held in other collections were identified for inclusion in this study. Using a portable XRF spectrometer and portable microscope, an additional ten objects were examined in situ.
Although XRF is very useful for identifying the elements present, from which the pigments used may be inferred, it does not provide definitive identification of many pigments, especially those that share common elements (for example the pigments lead white, red lead, and lead-tin yellow, which all contain the element lead), or are organic in nature (such as indigo). Fortunately, some of the institutions in which analysis was performed, notably the Art Institute of Chicago and the Metropolitan Museum of Art, made their Raman spectrometers available during the study visit for additional analysis of the manuscripts.
These techniques were supplemented in many cases by the ability to take photomicrographs of the leaves/fragments studied using a portable microscope. These images helped researchers compare the particle colors and types found on these manuscripts to the more thoroughly examined leaves studied at the Getty.
XRF analysis  XRF analysis 
Left: XRF analysis at The Free Library of Philadelphia. Right: Collection of digital photomicrographs at The Morgan Library & Museum, (shown: detail of Pacino di Bonaguida, The Trinity [MS. M.742]). Photos: Karen Trentelman. Image Credit: The Pierpont Morgan Library, New York.
Last updated: December 2012