Not ... quite...Originally Posted by jdef
*Most* paper bases are fiber. Ilford does make color papers with plastic bases - I think Kodak does also... but "RC" indicates that the fiber base itself is layered on both sides with polyethylene and is generally impervious to liquids ... yeah, yeah, I know, not the edges ... see "generally".
Having the base impermeable saves it form being soaked with liquid, therefore requiring long wash times, and curling, which, in itself is enough to "sell" me.