Restoring 17th-Century Vellum: Tools and Techniques

Ever wonder why some old books look like they are trying to fly away? You might have seen them in a museum or an old library. The covers are curved and warped, almost like they are alive. That is because they are covered in vellum. Vellum is not paper. It is skin. Specifically, it is calf, kid, or lamb skin that has been stretched and treated. Because it was once part of a living creature, it has a memory. It reacts to the world around it. If the room is too dry, it shrinks. If it is too wet, it expands and curls. It is one of the toughest materials to work with in the world of bookbinding. When you are trying to restore a book from the 1600s, you aren't just dealing with a cover; you are dealing with a material that is constantly trying to move.

What happened

Vellum covers from the 1600s often warp because they are made from animal skin.
Restorers use bone folders to make precise folds without scratching the delicate surface.
Custom-made presses apply even pressure to help the vellum stay flat while it dries.
The chemistry of the old inks must be studied so they don't wash away during cleaning.
The goal is to keep the book's historical look while making it stable enough to handle.

The Power of the Bone Folder

When a restorer needs to fix a crease in a vellum cover, they can't just use their fingernails or a plastic tool. Plastic is too soft, and metal can be too sharp. They use something called a bone folder. It is exactly what it sounds like: a flat, polished piece of animal bone. It feels smooth and heavy in your hand. This tool is vital for making precise creases without abrading the substrate. That is just a fancy way of saying it doesn't scratch the skin. You use the bone folder to rub the vellum down, coaxing it back into the shape it is supposed to be. It takes a lot of rubbing and a lot of time. It is a very physical job. You can feel the resistance of the skin as you work.

Under the Press

After the vellum has been cleaned or treated, it has to dry. But if you just leave it on a table, it will curl up like a dry leaf. This is where the book press comes in. These aren't just any presses. They are custom-fabricated with adjustable platens. Think of them like very expensive, very precise clamps. The platens are the flat boards that squeeze the book. By adjusting them, the restorer can make sure the pressure is perfectly even across the whole surface. If the pressure is off by even a little bit, the book could dry crooked. The book stays in the press for days, or even weeks, until the vellum 'forgets' its old warped shape and learns to stay flat again.

Inks and Pigments

One of the scariest parts of the job is dealing with the ink. In the 17th century, people made their own inks from all sorts of things. Some used oak galls and iron, while others used soot or ground-up minerals. These inks have different chemical profiles. Some are waterproof, but others will melt the moment a drop of cleaning solution touches them. Before a restorer does anything, they have to test a tiny, microscopic dot of the ink to see how it reacts. They have to be like detectives. They look for signs of deterioration that the naked eye might miss. If the ink is flaking, they might use a tiny bit of Klucel G to stick it back down. It is all about preserving the 'aesthetic and historical authenticity.' We don't want the book to look like a reproduction. We want it to look like a 400-year-old book that has been loved and cared for. It is a slow, quiet kind of work, but it is the only way to make sure these artifacts stay with us for another few centuries. It’s pretty amazing when you think about it—using a piece of bone and some clever chemistry to keep a piece of the 1600s alive.