"Laminating" is sealing between two sheets of plastic, each of which adhere (permanently) to the paper. No shellac or varnish. The procedure has not been popular for some time, and so almost all laminated items are fairly old. One problem, of course, is the yellowing of the plastic. In theory, laminated items are not much different than shellac balls--the handwriting has been permanently sealed under a clear coating. In one case the coat goes on as a liquid, in the other as a solid.
Here is an (unfortunately) laminated item in my collection, the front of a cover signed and addressed by Walter Johnson at the first Hall of Fame induction:
All-in-all, it's not too bad.
(Next thing I know, this very same Johnson signature will be appearing on repro baseballs.)