Here's another one that I had tried long ago. I only ever got the one vial to try.
Pen: Platinum Cool Crystal Rose F
Ink: J. Herbin Bouquet D'Antan
Paper: Rhodia No. 16 Grid
WTF. This is the lightest thinnest ink I ever encountered. All afternoon and night I thought something was wrong with the feed. I kept wicking more ink out but it always looked watered down. Definitely no bleed. I can't imagine that it would bleed. I can barely read it. I feel I have to put down lots of pressure to flex out the nib slightly to get some readability.
Well, looking back at the earliest lines, it does have nice shading. It dries darker. Just that writing is tiring. For me this ink is so-so. I might clean it out early.
As one who uses fountain pens primarily for writing rather than drawing or sketching, I still find this colour much too light. I think it would be quite good for ink washing. In fact, I think I pretty much the rest of the sample for prepping ink washed backgrounds for lettering use.