Francisco Trujillo’s talk was an excellent addition to the overall conference theme of ethical considerations and critical thinking as it highlighted the impact a conservator’s assumptions and biases can have on the course of analysis and treatment. He described the treatment of a Dutch illuminated manuscript, The Hours of Catherine of Cleves, in preparation for exhibition at The Morgan Library and Museum. The Book of Hours contains over 150 illuminated miniatures designed and painted by an artist known as the Master of Catherine of Cleves. The manuscript was originally bound as one volume, but was later split into two volumes and reordered. Treatment of the manuscript involved disbinding, consolidating the media on each page (with 1-2.5% isinglass in water and ethanol), and rebinding the folios in their original order.
As treatment progressed, Trujillo began noticing the presence of a non-copper based “smooth blue” pigment, possibly ultramarine. The “smooth blue” was found on pages that would have been facing each other in the original manuscript (before it was split and reordered) and was not found on surrounding pages. FCIR and XRF analysis revealed that ultramarine was present in these “smooth blue” areas along with azurite. Trujillo began to wonder if the Master had selectively used ultramarine on a handful of leaves, possibly mixing it with azurite, or if the ultramarine had been painted on top of the azurite, a later “sleight of hand”? Since at this point Trujillo had no other evidence that the Master ever used ultramarine, he assumed that the presence of ultramarine was a result of 19th century “touching up” when the manuscript was split into two volumes.
Trujillo pursued the “sleight of hand” line of inquiry, but then came across evidence that perhaps the Master of Cleves had, in fact, used ultramarine as an aesthetic choice. This led him to once again question his beliefs about the Master’s working methods; though there was evidence that many of the leaves had been “doctored” when the manuscript was split, there was also evidence that the blue pigments were mixed, quite possibly by the Master. He also found cobalt mixed into to some of the blues, and now leans toward the belief that it was the Master himself who used ultramarine on a select number of folios.
Trujillo did a nice job of calling attention to the assumptions conservators make about the objects they’re working on and the impact this can have on treatment decisions. He acknowledged that pursuing the “sleight of hand” theory – while fascinating – diverted his attention for a while and kept him from seeing other important evidence in the manuscript.