when cellotape fossilises, it goes yellow & brittle & you can pull it off - leaving a yellow shadow where it had been, & gloom & desolation if it's a precious book.

What is the difference between an invisible tape and a transparent tape? “Transparent tape” (Sellotape, Scotchtape) is glossy-surfaced cellulose tape. It will effect emergency repairs to torn paperwork, but over time it will yellow and become brittle, and the adhesive will give up. Its limitations are clear if you spend any time viewing documents from the first half of the 20th century, when it was the only repair option available.

“Invisible tape” is a thin polyester tape with a matte surface. On paper, it becomes almost invisible, because the matte surface reflects no highlights. It does not yellow with age, and joints I made with it more than fifty years ago are still holding up fine. It is more expensive than transparent tape, but if what you want is longevity, it is the best option. (read on for more comments)

Sometime after 1978 I repaired my mother's hardcover 1936 edition of Wind in the Willows at work using our 4" library spine tape together with a bit of invisible tape on the edge, but as a Library Supplies website says, tapes available 60 years ago are not the same as those available today, & the tape available at my library in the late 70s & 80s probably doesn't look as good as it did.

But it's much better than sticky tape, both tapes are still matte & certainly not yellow.

sandra (another retired librarian)