The Epson Premium Semimatte (260) is a completely different paper than the Epson Commercial Semimatte, & the Epson Standard Proofing paper (240).
I incorrectly ordered the Epson Standard Proofing paper (240) - 9mil, which is too thin for me. I just ordered the Epson Proofing Paper White Semimatte (255) - 9.9mil. Both lack optical brightners. The paper i am used to, Epson Premium Semimatte Archival Photo Inkjet Paper (16" x 100' Roll), is 260gsm / 10.9mil. What I am wondering, is if anyone can recommend a paper close to Epson Premium Semimatte Archival Photo Inkjet Paper (16" x 100' Roll), that comes in cut sheet (any manufacturer). Obviously Epson Proofing Paper White Semimatte (255) - 9.9mil is a good starting point.