9x6 is a standard print size (for us) via the Fuji Frontier to Fuji crystal archive paper but not considered to be a standard paper size for inkjet paper manufacturers, after all you can cut down an A4. Other "non" standard print sizes (for us) are 7.5x5, 10x7, 5x5, 8x8, 10x10 plus all the "normal" print sizes of course.