Different Types Of Shiny Gum On Americana Series ?

In Art Maniker's "The Americana Series Reference Manual", he lists two types of "shiny" gum used on some of those stamps - "shiny wavy" and "shiny flat". Are these intended production "types" of gum or gum application, or an "oddity" that "just happened" on some of them ? Thanks for any responses .

I guess my question(s) should be more like "were the types of "shiny gum" ("wavy" or "flat") inherent in their formulations, or were they an intentional - or unintentional - result of the method(s) of gum application during production of the stamps?

by wavy, do you mean what I have heard called pebble surfaced?

eyeonwall - I'm not sure, but I think so. I've seen "pebbly" and "flat" - I'm not sure if I've seen "wavy" , so I'm kind of lost on this . . .Going through my Americana collection, I've seen everything from "shiny, barely grainy" to "shiny VERY pebbly" - as a comparison, 220 grit sandpaper to 80 grit sandpaper. Unless somebody comes up with an explanation of different textures of "shiny" gum, I'm just going with the assumption that they are all the same except for the amount of gum that had been applied and maybe the rate the gum dried . . .

or maybe how it was applied?

eyeonwall - yeah, there's that to consider, too . . .