I saw a review in which the reviewer discovered that she had perhaps been using the wrong side of the paper, and she was delighted by the performance of what she thought was the reverse, so just in case, I flipped my test swatch over and painted the same silvereye on the reverse side. This side had even less surface sizing and colors faded to dull, so that nixed that concept.
Review/Test 1: Lanaquarelle 300 lb rough watercolor paper