You might have more luck asking for Kentmere Art paper. Luminos were the North American distributor and re-branded it. My experience is without a super coating it didn't keep as well as other Kentmere papers and it's some years since it was last made (2007).
Ian, waay late to this thread but were all the Luminos papers rebranded Kentmere papers? There were a few I really liked, and I realize that the "new" Kentmere has zero to do with the old stuff.