I was intrigued with a technique Glenn Vilppu demonstrated recently in his New Masters Academy video, Drawing with a Fountain Pen and Waterbrush. What he does is draw with a fountain pen, usually a Pilot Namiki Falcon pen, which has a nice semi-flexible "soft fine" nib. Then he goes back and reactivates the inked lines into a wash using a Niji or Pentel waterbrush. I came across a youtube video from 5 years ago, Drawing from the Old Masters, lesson 166, in which he was using the technique, so he's been doing it for some time.
In his New Masters video Vilppu uses mainly a Namiki Falcon pen, and a Pilot Vanishing Point pen. He also uses primarily Pelikan Brilliant Brown ink, although he gradually mixes in other inks as convenient. I also noticed Steve Huston drawing with a fountain pen. In his case the pen was a Faber-Castell LOOM pen. Fine nib.
I was curious to try out their drawing methods, and on the strength of the fact that Vilppu and Huston wewre using those pens I bought them for myself. I got the Faber-Castell LOOM pen first, and I enjoyed using it. When I got the Pilot (formerly Namiki) Falcon I found that it definitely provided a better drawing experience. The flexing was minor, and required a bit of effort, but the smoothness and ease of drawing was greater in the Falcon. When I returned to the LOOM I found it was somewhat scratchier on the paper.
My main concern was with the inks. I wanted something that behaved in a manner similar to what I had seen in the New Masters videos. Normally I guess one wants an ink that dries fast and is relatively waterproof to the extent a fountain pen ink can be waterproof without ruining the interior of the pen. In my case I wanted the opposite: I wanted an ink that could be 'reactivated,' and possibly even erased, through the addition of water onto already dried lines.
Waterman's Absolute Brown
This was the first ink I tried. I think it's the one Steve Huston was using in his sketchbook techniques video. It worked well for me. I particularly liked how un-waterproof it was on the page. I was able to reactivate and even erase the lines I had drawn with it. I would have preferred a less red, more orange-yellow hue, but I was happy enough with this color. Losing the drawn lines turned out not to be a problem, since any really important lines can be re-drawn to reintroduce or strengthen them.
J. Herbin Lie de The
I agonized over this one for a while, since many of the online samples I saw of it seemed too green for my taste. In the end I sprang for a bottle, and I quite liked the color. I don't think I'll use it for the waterbrush reactivation technique, though. The color is too faint in a wash, disperses into hue overtones I don't like, and the ink is too water-resistant. The lines stay too visible, although they take on a weird semi-opaque white covering. I like this ink a lot on its own coming from a pen. I don't like it after it receives the waterbrush treatment.
Pilot Iroshizuki Tsukushi
After a few passes with the waterbrush this ink looks a lot like a more color saturated, more water-resistant version of Waterman's Absolute Brown. That makes it slightly less useful for my particular needs than the Waterman ink, even though it is much more expensive. I'll use it both as a pen ink and as a wash ink until it's gone, but I won't race out and replace it.
Pelikan Brilliant Brown
This is the ink Glenn Vilppu recommended in his video. It diffuses into slightly odd, bright colors when activated into a wash, and it has a similar 'white opaque covering' that develops over some of the lines similar to that created by the Lie de The ink. I like it in a pen, but less so in a wash.
For me the winner was the Waterman's Absolute Brown. I like how mysterious and watercolor-like it can become, erasing most of the lines and forming a moody tone. I also like how I can always go back and redraw or reinforce any important lines that became too weak or vanished.