Arches Platine has been a solid staple of alternative photo printmaking community for a long time!
It comes in two weights: Light Arches Platine-145 gsm and Heavy Arches Platine- 310 gsm.
Both weight works perfectly for processes such as Cyanotype, Platinum Palladium, Albumen, VanDyke Brown, Salted Paper, and Kallitype.
It is a Natural Bright White with a very hard surface sizing. Do not use tween or water before coating as this paper does not need any surfactant and will absorb the chemistry very readily. The 11x15 will have 3 cut sides and 1deckled edge. The 22x30 will have 4 deckled edges.