Polyester film (Mylar, Duralar, etc.) on leather books?

I have recently started covering all of my fine books, however expensive, in clear polyester film to protect them from damage during storage and handling. But I have seen conflicting advice about the use of such film on leather books: some say such use should be avoided so the leather can breathe and pick up oils from handling, others seem to say it's fine to cover them.

The thing that gives me pause is that I have a bunch of quarter- or half-leather volumes whose paper/cloth sides I'd like to protect, even if the leather is more robust. Can anyone advise on best practice?

>1 ubiquitousuk:

I am firmly NOT in the "handle them and soil them with your sweaty and greasy bear paws" school of thought and the leather, vellum, etc., does NOT need "to breathe". It is important to not use any cheap plastic or acrylic; rather, I suggest using Dura-lar Grafix which is an archival material that will not interact with any material. It does not yellow, crack or stiffen over time, it protects leather from drying out, and it keeps your bindings clean and safe. Use .003" thickness for routine books and .005" thickness for folio-sized and/or very heavy books. I have used it on all my private press books for decades without adverse effect.

I have a some 45-year-old Franklin Library books and some 30-year-old Eastons that look and feel as good as the day I bought them without any treatment or protection, so I wouldn’t do anything to your full leather books. I suppose the partial leathers would depend on the other fabric.

>1 ubiquitousuk: I'm assuming the animal with which your books are covered are no longer alive, so I'd say they no longer require any room to breathe.

For what it's worth, one local antique book collector in my neck of the woods has probably one of the most valuable private book collections in the world. He doesn't cover his leather books in anything. Just keeps them stored in a temperature controlled room.

There's no need to cover your leather books if they are in otherwise good condition. The oil from your hands is actually good for the leather. Just make sure your hands are clean.