Franz Ehrle (1845-1934) and book conservation
Franz Ehrle (1845-1934), a Jesuit scholar and prefect of the Vatican Library (1895-1914) paid special attention to book conservation, which became an internationally recognized profession under his supervision. One of his major initiatives was the coordination of the international conference in St. Gallen (Switzerland) in 1898, when he invited the directors of the main European libraries to discuss the challenges of book conservation. In his vision of improving the “health condition” of ancient manuscripts and documents, Vat. lat. 5757 was an important case study of palimpsests that carry important texts of high philological value but which are at risk of further deterioration, especially as a result of Mai's use of chemical reagents in his process of deciphering. Along with his major discoveries and accomplishments, Mai also effected an deterioration of the parchment that continued to turn increasingly dark and highly fragmented in some parts. These phenomena are less severe in Vat. lat. 5757, which, however, as a widely known celebrity manuscript, was useful in defending the case of its less known but more damaged fellows. Franz Ehrle brought a couple of folios of Vat. lat. 5757 with some other manuscripts to demonstrate his views on damaged palimpsest folios treated by Angelo Mai in the Conference in St. Gallen.
At the conference, Ehrle made the following two major points regarding palimpsests. First, he supported the idea of using gelatin in the conservation of palimpsests that suffered from the treatment of Gallic acid, or Gioberti tincture, and had consequently become dry, fragmented and dark brown or black. After the application of gelatine to prevent deterioration of the Gallic acid's effect, bifolios were protected in separate conservation folders or between glass sheets to hold the fragile parts together. Because of light reflection, gelatin makes photography of such folios very challenging. Second, he stressed the potential service of photography for the conservation of books, namely that analogous photography can produce photo reproductions that simultaneously facilitate research and help conservation of old and fragile material.
At the International Conference in St. Gallen on October 1, 1898, Ehrle launched the Vatican series of facsimile editions, Codices e Vaticanis selecti phototypice quam simillime expressi, mentioning Vat. lat. 5757 among the codices initially selected. Ehrle was the first who thought of making a photographic facsimile edition of entire manuscripts with palimpsests just like the editions made for more easily legible manuscripts, for the purpose of conservation. He brought his idea to light in 1906 by publishing the facsimile of Vat. lat. 5750, another Bobbio palimpsest (M. Cornelii Frontonis aliorumque reliquiae quae codice Vaticano 5750 rescripto continentur, Mediolani 1906 [Codices e Vaticanis selecti, 7]). He was able to accomplish this with glass plates which were made by Giulio Danesi. The facsimile edition of Vat. lat. 5757 was published later, in 1934. These two facsimile editions are still excellent, historical examples of Ehrle's farsighted vision that photographic reproduction simultaneously helps conservation and scholarly research of fragile manuscripts, including palimpsests.