Stains Alive! BiblioPhilly and Labeculae vivae: The categorization of stains in alchemical manuscripts using multispectral imaging

Fifty-two discoveries from the BiblioPhilly project, No. 8/52
A guest post by former Schoenberg Institute for Manuscript Studies CLIR Fellow, Dr. Erin Connelly

Recipes and extracts on alchemy, medicine, metal-working, cosmetics, veterinary science, agriculture, wine-making, and other subjects, Northwestern Italy, Probably before 22 December 1438. Philadelphia, Science History Institute, MS Othmer 1, front cover

Labeculae vivae was a project supported by a microgrant from the Council on Library and Information Resources (CLIR). The project ran for one year, from August 2017 to September 2018, during which stains from about forty Western European manuscripts, ranging from the twelfth to sixteenth centuries, held in the special collections of five partner institutions, were imaged, and subsequently analyzed. In 2016, the Bibliotheca Philadelphiensis project catalogued manuscripts from the Science History Institute and its Othmer Library of Chemical History, which houses over 140,000 objects, including an invaluable collection of medieval alchemy manuscripts. Prior to the recent work of the BiblioPhilly project, these manuscripts were undigitized and several have never had a printed edition. The team members of Labeculae vivae1 performed multispectral imaging and analysis on a selection of alchemical manuscripts from the Science History Institute based on stains identified during cataloguing by BiblioPhilly. 

Many of the most interesting manuscript stains are found in the bindings and folios of soiled, heavily-used medical and alchemical texts. Signs of this practical use may be obvious, such as burn marks from furnaces, but innocuous-looking stains (e.g. appearing to be water damage) may contain hidden information about medicinal or chemical solutions, or even heavy metal contamination, which is not evident by sight alone. The majority of manuscripts identified as potential candidates for stain analysis have never been accessible in either print or digitized formats. This is especially true of medical and alchemical texts, which are often less well-known than medieval literary works and may be considered less “beautiful” than the illuminated and decorated texts commonly regarded as world treasures.

As an example,2 we can highlight the analysis and investigative process for Othmer 1 of the Science History Institute, a manuscript from North-Western Italy, dated before the end of 1438, containing “Recipes and extracts on alchemy, medicine, metal-working, cosmetics, veterinary science, agriculture, wine-making, and other subjects.”

MS Othmer 1, fol. 68r

When making a first plot of the spectral curves of the various components of the page, we considered the larger bicolored stain as one component, conjecturing that the central core might be a more concentrated element of the same substance throughout the stain. This has a unique shape that was not reconcilable with anything else on the page, and followed only slightly, as is often the case, that of the paper substrate, since it did not cover it completely, masking its spectral response (see image below).

Plotting the spectral curves for the stain in the middle of the columns as a composite

A Principal Component Analysis (PCA) investigation, however, led us to notice the spectral response of the ruling ink, as opposed to the writing one. This also evidenced the pale yellow-brown components of the large stains, but not the greyish core. Further analysis showed that the central greyish core, resembled the response of the writing ink (see image below). This led us to plot the spectral response a second time, and to separate the two components of the central stain in two different spectral curves: one for the inner darker spot, and one for outer light-colored area. The new curves followed the same respective patterns of the writing ink and of the ruling ink (see second image below). As it is clear from the analysis, the stain must have occurred at the time of writing, and not afterwards. The stain thus reveals the work of an untidy scribe, who spilled the ruling ink pot on the recto of folio 68, and then also dropped some writing ink on the same area, resulting in the composite stain that we can see today. This gives us clues regarding the kind of manuscript that Othmer 1 is: a working copy important for its content and not for its appearance.

False color image showing different ink components highlighted in different colors: ruling in yellow, writing ink in red, and rubrics in blue; the central stain shows similar color configurations: inner core in reddish tone and outside area in yellow

Plotting the spectral curves for each component of the central stain, revealing patterns similar to the writing and ruling inks

Similar to BiblioPhilly, the main objective of Labeculae vivae was to reveal and make available new information about lesser known medieval manuscripts in order to provide a foundation for further scholarly endeavours. Along those lines, over the course of the Labeculae vivae project, we have collected about 220 Gb of data that is now hosted by OPENN, University of Pennsylvania Libraries.3

  1. Dr. Alberto Campagnolo, Dr. Erin Connelly, and Dr. Heather Wacha (CLIR postdoctoral fellows at the time of the project), with the generous help of Michael (Mike) B. Toth from R.B. Toth Associates and Dr. William (Bill) Christens-Barry of Equipose Imaging.
  2. This excerpt of text and figures is from Alberto Campagnolo, Erin Connelly, and Heather Wacha, “Labeculæ Vivæ: Building a reference library of stains for medieval and early modern manuscripts,” in Manuscript Studies, A Journal of the Schoenberg Institute for Manuscript Studies (forthcoming 2019).
  3. The repository (ark:/81431/p35d8nj0r) is maintained by The citation URL is