I wrapped the book in plastic, and glued the new spine liner with false raised bands (same dimensions as the original remnant) to the plastic. Many steps left undescribed.
Here the book with new hollow, layer of thick paper pasted on and then sanded down to even out the bumps caused by the new reinforcing linen cords. The book was wrapped in plastic, new spine liner and raised bands glued to plastic, new repair calf cut using pattern.
While the dyed leather was drying, I lifted some more of the pastedown, then flattened it out.
Lifted portion folded back over white paper, showing bare board. I put mylar in here before closing the cover, so the underside of the old paper wouldn’t stick to the fly leaf.
Using a sharp knife to cut through the old leather turn in at the edge of the board. When the new spine is put on, it will be pasted underneath this lifted piece, so that the old leather covers up the new. Don’t ask how nerve-wracking it is to cut into beautiful, dry, brittle, gold-tooled leather almost 180 years old. My blood is ice! I OWN this! Plus, the book gods were kind.