When Kodak first introduced their T-Max films in 120 roll-film, the base was thicker than other roll films. This caused some problems in some cameras, but later on the base became thinner than then but still seemed a little thicker than others, and maybe still is. I don't know. The information sheet packed with the films used to give the thickness but I haven't bought any for years so can't quote what it is.

Over the years Kodak & Ilford backing papers seem to have got thinner than they used to be.