So once the charts were disbound (that part is here), they sat in a stack under light weight for a good long while until I decided how to rebind them.... I didn't mention in the last post that although they look a bit grimy, there isn't a lot I can do about the dirt besides just brushing with a soft brush: all of the pigments are water-soluble, and the parchment itself, although quite thick and nice, would react to moisture as well. The remaining dirt will just be part of the book's history now.
In terms of structure, the new one would be quite similar to the old one with a few tweaks. For the guards, Michael Gibbs of Griffin Mill made us this really wonderful paper (Akbar natural, 115 gsm-above). As you can see in the photo below, I cut it into strips a little longer than the leaves, which are all slightly different sizes and none of them quite square. Each parchment bifolio would have a wider attachment guard, and narrower compensation guards nestled inside to build the paper area up to the thickness of the parchment. Some parchments needed two compensation guards, some just one, to build up to the right thickness for the overall textblock. My plan was to cut them down to the right height individually after they were attached.
For adhesive to attach the guards, I finally decided on Beva 371 film. Originally developed for lining paintings, it comes as a liquid or as you see above, a thin film between two backings. It can be activated by heat, which is what drew me to it: the glass transition temperature is 65 degrees Celsius, so it shouldn't affect the parchment too much, and will avoid problems that I would have with the pigments if I used any water-bound adhesive. The stability of Beva has been well-documented; the concern here is the removability of the adhesive: should the book need future work and someone needs to get off the Beva, it may not come off completely. In practice, though, the more traditional gelatin wouldn't be entirely removable just because it softens in water (and then the old pigment problem reappears...). Parchment has a fibrous texture at the surface that will grab anything that goes on it, and the truth is that every treatment we do will permanently affect the object. In this case, I decided that the most cautious plan of action was actually to use the synthetic modern adhesive, because it would have no effect on the pigments, and after a few rebindings the value of this atlas really lies in the images.So. Because the leaves were all uneven, I made a template with three walls and the dimensions of the paper leaves at the beginning and end. You'll recall that since the parchments had the guards, they're narrower than the paper leaves, so I needed to make sure each parchment bifolio (of varying size)/guard combination ended up being as close to the size of the paper leaves as possible. That let me clamp the guard in place along the un-walled edge, and back the parchment into the walled side, then use a tacking iron to get them attached.
The Beva film comes with a clear plastic backing on one side, and a white paper backing on the other. I cut it in strips, then took off the white side, and ironed through the plastic side to adhere it first to the paper guards.
Then I clamped the paper in place, Beva side down...
And ironed through the paper until the Beva stuck.
The cockled parchment actually was really helpful in showing when the Beva was hot enough to hold the parchment: when it's adhered, as at bottom left in the image below, it takes the shape of the parchment.
When all the guards were attached, I trimmed the excess from both sides (above). Then they were even with the edge of the parchment, but uneven with each other. Below is the stack without the compensation guards. You can see how the paper side is much thinner than the parchment side without them.
Meanwhile, the fills on the paper leaves were finished. The missing pieces along the spine edge were filled with western paper (that's the brighter spots you see along the bottom edge in the photo above), and the entire thing extended with a thick kozo paper to give a flexible fold at the spine through which I could sew the papers into the binding. And with that, I wrestled it onto a sewing frame. I was a little too short and the book was a little too big...
I laced it into boards and sewed on endbands in plain linen thread. You can see in this photo that after sewing, I trimmed the edges of the compensation guards flush (-ish) with each other to give an even edge against which to endband, even though the leaves vary quite a lot in height.
And from there it was covered in half parchment with handmade (Twinrocker) paper sides. It's getting a gilt (stamped) title label and shelfmark, and a drop spine box to keep everything flat and protected. Here's the finished thing:
