I already had about a dozen different shades of blue ink by various manufacturers (Diamine, Herbin, Pelikan, Parker, Sheaffer) when I received with one of my orders from Truphae a handwritten thank-you card in Private Reserve's "blue suede" ink. It was such a distinctive shade of blue that I had to order a bottle, and I'm very glad I did. The ink is vibrant and so saturated that the color doesn't appear wan even when used with a Japanese (Pilot) fine nib. The hue is reminiscent of, but definitely bluer than, Diamine's "aurora borealis." The flow is excellent, and I have noticed no feathering, even on lesser grades of paper. The only quibble I have is that there is slightly more bleed-through on cheaper paper than one gets with Diamine or Herbin ink, but this doesn't prevent my rating it five stars--a rating that is all the easier to give because of the generous quantity of ink (60 ml) for the price.