Palimpsests are not easy to visualize online because they are most often illegible to the human eye in natural light and have multiple identities. In addition, the discarded texts are almost always incomplete and their order has been changed according to the sequence of their writing surface as reused for the upper script. Solutions to resolve this set of challenges vary but they tend to treat palimpsests apart from the manuscripts which lack such complications. In the Vatican Library, each palimpsest page with the slightest promise of legibility is normally reproduced by two different scans or photographs, both in the identical position, one with natural light and the other with visible fluorescence generated by UV light.
Vat. lat. 5757, p. 260 - image with natural illumination (on the left) and image with ultraviolet illumination (on the right)
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At the end of the digitization project, these two, or in exceptional cases, three (Pal. lat. 24) or four (Vat. gr. 770) images per page are published on the visualization platform of the Vatican Library so as to be easily accessible to interested readers all around the world. This collaborative teamwork between the conservator, the photographer, the specialists of image processing and Information Technology aims to provide scholars with the best possible means to study the Vatican Library’s holdings. The Vatican Library publishes its manuscripts both with and without palimpsests on the same platform.
The pathway of Vatican Palimpsests explored Mirador’s capacity to integrate the additional identities of palimpsests into the same manifest (the sequence of all images of a manuscript with metadata) both in terms of adapting the sequence of images to these special manuscripts, as well as the metadata which record and highlight the information linked to them. Each manuscript with its recycled writing surface is provided with a collation of the included gatherings or quires which enables readers to establish the correspondence between the two parts of the folded folio without access to the original. As one may expect, Mirador’s IIIF compatibility permits parallel visualization of the same manifest one next to itself, i.e. the comparison of multiple variants of the same page or manifests of other manuscripts from anywhere on the world which are published online.
Mirador's particular visualization and virtual enhancement tools (rotation, brightness, contrast, saturation, gray scale, inversion, mirror and return to the default version) are especially useful in deciphering the images of palimpsests that are difficult to read.
Mirador's tools
The mirror function, for example, was added in view of the Vatican Palimpsests pathway in order to visualize the scriptorium where the parchment bifolios of an old manuscript were clear-washed and then recycled in the 13th century in South Italy (see below Vat. gr. 316).
Vat. gr. 316, ff. 99v + 96r
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In the sequence of images, Mirador viewer is able to add modified versions of an image which is different from its default version; i.e., parallel visualization of the same page according to the upper and lower scripts.
Urb. gr. 154, f. 128v (and f. 128v rotated 90° ac with ultraviolet illumination)
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