This ink has sufficient saturation to ensure a good, dark line even for someone (like me) who writes fast with a fine (Japanese) or extra-fine (German) nib. On some types of paper there will be traces of bleed-through and/or feathering, but that is probably an unavoidable corollary of a consistency that provides a flow that can keep up with faster pen strokes. I have not had any problems with skipping, no matter how fast I write. The only reason I haven't rated this five stars is that it's quite a bit more expensive than some competing manufacturers' inks of comparable quality. That said, I will in all likelihood keep a supply of this "Perle Noire" on hand.
Herbin Perle Noire Ink