Scientific Analysis

Dr. Silvia A. Centeno, Associate Research Scientist, The Sherman Fairchild Center for Works on Paper and Photograph Conservation & The Sherman Fairchild Paintings and Conservation Center at the The Metropolitan Museum of Art, performed in situ Raman microscopy and x-ray fluorescence (XRF) on pigments, inks, and other materials used by scribes and artists in the Prato Haggadah.

Unlike other methods of analysis where minute samples must be removed from the manuscript for examination, in both Raman light spectroscopy and XRF analysis, no samples are required as these methods are non-destructive. In Raman light spectroscopy, a sample is illuminated with a laser beam and the scattered light frequencies emitted are used to identify the sample by comparing the Raman spectrum with a known reference material. XRF analysis allows the study of fluorescent light emissions of x-rays to identify elements examined.

The analysis indicated that the pigments and other materials detected were all consistent with the medieval palette: azurite, vermilion, orpiment, copper green, lead white, red lead, carbonaceous black, and red organic pigments or dyes. Identification of pigments used in the manuscript enables the conservator to adapt treatment to the special needs of individual colors that may react in different ways. Moreover, the analysis provides a record of the materials used in the making of a Hebrew manuscript in medieval Spain. Identification also provides information on the light-fast (or fugitive) characteristics of a pigment and thus determines the allowed exposure for exhibition.

As no analysis of this type performed on Hebrew manuscripts of this location or period is known, Dr. Centeno's examination will expand our knowledge of the working practices of scribes and illuminators of Hebrew manuscripts from early fourteenth- century Spain. It will also facilitate a comparison of these practices with other Jewish, Christian, or secular manuscripts.