Readers are asking which paper Wolf Kahn uses, and especially since he has spoken against sanded papers. I doubt that WK would want to be known for proscribing any art materials or for any "rules" in art making. He tends towards the creative expression and loose side of the house, I think. My feeling is that he expresses his own methods and that's that.
Far be it from me to tell anything more than what I have seen or read about the master's materials. I did buy Diane Townsend's Wolf Kahn Terrages, which as far as I know is the only product he's ever endorsed. I did find the following vague reference to WK's paper choice.
This is the pastel that I worked on with Wolf Kahn because he is particularly fond of the gritty formula. He likes to break open the surface of a paper like Lana paper and work the color directly into the fibers of the paper.
Diane Townsend, reference.
You might recognize the Raffine product name, which derives from Lana, in France.
Raffine at Jerry's.
The pastels of Kahn's that I saw in NYC were wonderful. His very loose (scribbled) style is a foreshadowing of his layered approach to oils. Then, he finishes with electric colors that pop as only intense pastel sticks can do. Imagine a thatching of burnt umber, then a heavy line of Sennelier Ultramarine over the top. The paper that is made in the cold pressed manner (think: rough, versus hot pressed, which is like an ironed flat pair of pants) is appropriate to this style. You simply can't scribble into sanded paper very effectively.