Murasaki-Shikibu is a mid-purple, not too red and not too blue, sitting between Iroshizuku Ajisai (bluer) and Yama-Budo (redder). I believe it is similar in tone to Jacques Herbin Violet Boréal (Les Essentielles coll.), Taccia Murasaki and Diamine Lavender. It looks bluer than Waterman Tender Purple and Röhrer and Klingner Cassia.
It is a nicely saturated ink, with some golden-green sheen visible only in heavily saturated areas where the ink pooled in swabs: during normal writing I’ve observed none, even with my wet Sailor 1911L 21 kt H-B. It doesn’t feather on my Japanese papers, but does so on Oxford Optik paper. The ink has a wet, smooth flow, presents a little sheen and some shading depending on the papers and pens used.
It is readable in all my Sailor 1911 L and S pens, with all nib sizes from H-EF to H-B, even in my 1911S 21kt H-M, which is a dry writer; the ink coats the nib fairly well, though I would have expected it to be thicker under the nib. I’ve experienced no skipping, no hard starts, no bleed through, some to-be-expected ghosting on thinner papers.
Murasaki-Shibiku is a lovely colour, but I prefer Jacques Herbin Violet Boréal because – strangely enough for an Herbin ink in my experience – it feels more lubricated, and the nibs glide across the page when I use it.