The examination of unknown sources reveals that by the end of the fifteenth and the beginning of the sixteenth century, there was a widespread awareness in Italy of the damage produced by the passing of time on books and manuscripts. The expression used to describe such cases was lettere svanite or caduche, which indicated that the writing had faded and was almost unreadable, and, as such, hard to transcribe, indicating that the manuscript needed to be preserved from further damage. Already between 1550 and 1552, in Rome and Venice, some ecclesiastics of the Roman Curia attempted to brighten ancient writing, using vegetable distillate high in tannin. In two cases, it is possible to identify manuscripts processed with this method and to determine the preservation formula as well as an accurate description of each step of the method. The process, now brought back to light, anticipates the chemical experimentations by the Benedictines of St Maur and other techniques, widespread in the eighteenth century, and their basic chemical principle, namely the application of tannin. However, the earlier technique is paradoxically much more complicated than the one applied two centuries later.

对未知来源的检查表明，到 15 世纪末和 16 世纪初，意大利普遍意识到时间流逝对书籍和手稿造成的损害。用于描述这种情况的表达方式是lettere svanite或caduche，这表明文字已经褪色，几乎无法阅读，因此难以转录，表明需要保护手稿免受进一步损坏。早在 1550 年到 1552 年之间，在罗马和威尼斯，罗马教廷的一些教士就试图用单宁含量高的植物蒸馏物来增亮古代文字。在两种情况下，可以识别用这种方法处理的手稿并确定保存公式以及该方法每个步骤的准确描述。这个过程现在被重新曝光，预示着圣莫尔本笃会的化学实验和其他在 18 世纪广泛流行的技术，以及它们的基本化学原理，即单宁的应用。然而，