Tag Archives: vellum

Slipcase Race

One of the Lab’s big projects recently has been to help the University of Cincinnati’s Classics Library with preparations for a move of a large section of their collection’s rare books. Moves like this are a great opportunity to assess the condition of a collection, and to provide enclosures for more vulnerable materials so they are protected in transit and beyond. In this particular case the Librarian also requested the lab maintain visibility of the original books as much as possible.

There are quite a few vellum books in the Classics Library collection. Vellum bindings are generally pretty sturdy, but may become brittle over time. They can also expand and contract quite a bit more than other types of bindings, depending on the relative humidity where they are stored. The Image Permanence Institute at the Rochester Institute of Technology has a fun time-lapse video demonstrating this effect – the book looks as if it’s haunted! Given time this expansion and contraction can cause distortion.

Hard-sided slipcases do make it possible to protect most of a book while keeping its spine decoration and information visible, but they are not generally a preservation go-to. They can abrade the edges and covers when pulling the book in and out, and they don’t usually hold up over time because it can be difficult to insert fingers around the book to pull it out if the case is tight, resulting in a broken box or, alternatively, damaged endcaps.

A soft-sided slipcase can work well for vellum-bound books. The vellum is smooth, so abrasion is not a concern. The flexible sides give a little when reaching fingers in to remove a book, so the box won’t eventually fail and there is no need to grab the book from its endcap, damaging it. The cloth allows the book to breathe and flex somewhat, while at the same time preventing it from expanding too far at the fore edge, and squeezing its neighbors.

With a deadline looming we needed to figure out a way to produce soft-sided slipcases quickly and easily. Our solution was to create a template in an Excel spreadsheet, allowing us to simply plug in the book’s measurements and know exactly what size to cut the cloth and where the creases need to be, without needing to have the book handy.

We measured several books where they were, then took the measurements back to the Lab, where we used the spreadsheet to make a handful of slipcases. I was holding my breath when the time came to unite them with their books. Much to my relief  they fit perfectly!

Check out this picture showing 4 vellum books – the one on the left was already housed in a hard-sided, cloth-covered, board slipcase, while the 3 on the right are in the brand new soft-sided cloth slipcases. The books are protected, but the spines are still visible. Win, win.

Now that we know it works it’s time to go ahead and make the rest of them!

We’d like to share the Excel spreadsheet used to create these slipcases – Soft-Sided_Slipcase_template.  Try it out and let us know what you think!

Veronica Sorcher (PLCH) – Conservation Technician

 

Fun with PhotoDoc – RTI (Edition 5)

At the beginning of April I was lucky enough to attend a RTI (Reflectance Transformation Imaging) workshop offered by Cultural Heritage Imaging (CHI) at Yale University.  CHI is a non-profit organization  that shares and teaches RTI and Photogrammetry technology with cultural heritage institutions around the world.  The class I attended was a 4-day NEH grant sponsored course taught by three RTI experts from CHI, and it was amazing!

This is a composite image of all the highlight points from one RTI section. The software uses these highlight points to map the surface shape and color of your object.

So, what is RTI?  CHI describes it on their website as “a computational photographic method that captures a subject’s surface shape and color and enables the interactive re-lighting of the subject from any direction”.  For highlight RTI, which is the least expensive and most accessible method for most institutions and what I was taught in the class, you basically take a series of 36 to 48 images of an object where everything is constant (settings and position of objects, camera and spheres) except for the light position.  With a reflective black sphere (or 2) set up next to your object, you move you light source around the object at varying angles.  Then, you take that set of images and plug them into the free RTI software provided by CHI and the algorithm detects the sphere(s) and the highlight points (from your light) captured on the sphere(s) and voila!…you have an fun and interactive way to look at your object’s surface texture.

Before I attended this fantastic training opportunity, our conservator and I knew right away what the subject of our first capture would be when I returned…a 16th century German Reformation text by Martin Luther with a highly decorated cover that is practically invisible under normal illumination.

Here’s a time lapse video of our first (and second) capture in the Lab…

That day (Tuesday) were were able to capture the upper and lower covers of the Reformation text (from ARB), the original silk cover from a 17th century Chinese manuscript (from Hebrew Union College) and an illuminated page from a German vellum prayer book (from PLCH).  And here our some snapshots of our results from two of those captures (click on the thumbnails for a larger view of the image)…

This possibly 13th century German Prayer Book has a full stiff vellum binding and an illuminated first page.  The varying modes highlight condition issues like worn/abraded parchment and flaking gold illumination, as well as the overall surface texture of the illumination.

I hope you’ve enjoyed getting a little sneak peek into RTI.  I will be demoing and discussing in further depth this afternoon from 1:30 to 3pm at the Lab’s annual Preservation Week Open House.  I also hope to do more RTI captures/processes in the future and share them here.

Jessica Ebert (UCL) – Conservation Technician