Signature Bindery

Looking for some insight… I’m intrigued by the ruled lines on the first page of this signature. Can I assume that this was a typesetter’s composing proof of some sort? It is only on the first leaf, front and back. I am well familiar with these rules on manuscript leaves but I haven’t come across a printed page with them.

We recently enjoyed the opportunity to repair and rebind a Fourth Folio of William Shakespeare (1685). There were many small tears throughout the pages, as well as about a dozen pages that had the margins cut off right to the printed borders. Sadly I’m guessing there was a decent amount of marginalia that a later owner didn’t appreciate. We extended out all those margins, repaired the title page, removed a very inappropriate modern binding then rebound it in a more period style. Always a treat to work on old

Apparently I have opened a cat café at the bindery.