First of all, on our boxes of S-RACE cut sheets there is an information which says: "Please notice, the top side (yellowish side) is the printing side. Don't print on the brighter side!"
So, if you open the box by removing the lid, the side facing up is the side to be printed. In case the paper is upside down in the box, we have two possibilities to find out the printable side:Hold a sheet of paper against the light - the printable side is completely matt (due to the microporous coating), while you can see a clear reflection of light on the rear (the rear side is not coated).
A second way is to flip the first sheet, compare the colors of the paper, the yellowish side is the printing side.
Please also notice, how the paper has to be placed in your printer.