I asked Jon, and he explained for convenience all the workshop printers were set up for "P2" and used "P2" curves for matte/rag printing. "P2" is Piezography 2, which if you are not familiar, uses shades 2-6 with both matte and glossy blacks and Gloss Overprint, to be able to print matte and gloss with one printer. You can use "P2" matte and rag curves, even if your printer is set up with regular K7 ink shade placement, but "P2" gloss curves can only be used with the "P2" ink setup (which you don't need with a printer such as the 3800/3880, that has enough channels to install both blacks, shades 2-7, and GO).
Here are the P2-SEL curves that you used in SantaFe. Please let me know if you have questions, how things look, or if there's anything else I can help you with.
Best regards and happy printing~ Dana
P2-SEL-MATTE.zip (13.1 KB)