Okay, so this is the Pentel FRH-MN (or FRHMNBPA), which is a way more helpful name when searching for the pen than the pen’s actual name, the Pentel Arts Aquash Pigment Ink brush pen in “light black” (which is the only color it comes in, anyway).
The name of this pen drives me nuts. Aquash is Pentel’s line of water brushes — they’re brush pens with empty reservoirs that you fill with water and use with watercolor paints. This pen is filled pigment ink and is not marketed for use with water or watercolors. The reservoir-style body is a feature in many of Pentel’s brush pens, so why does this one need the “Aquash” name? It’s not a water brush!
Pentel Arts also has a Color Brush line (Art Brush for the Japanese edition), which uses dye-based inks. It would’ve made more sense to do something like “Color Brush Pigment,” wouldn’t it? (Wait, wait, Pentel does have a Color Brush with Pigment Ink?? But it only comes in black, in three tip sizes, and is not this pen. Why.)
Jetpens had the Japanese version of this pen listed as the Pentel Seiboku (青墨) but that just means “blue ink,” and it’s unclear to me if that’s actually supposed to be the name of the pen. Pentel Seiboku is a helluva lot shorter than Pentel Arts Aquash Pigment Ink Brush though! But also, if the ink is supposed to be blue, then why the heck did Pentel of America translate it as “light black”?
But I digress…
The Pentel FRH-MN has a medium-sized, synthetic bristle tip about 14 cm long and 3 cm at the base. This is noticeably bigger than the Pentel Pocket Brush, which makes sense since it isn’t a pocket brush.
Brush integrity is excellent, with the tip snapping back reliably after each use. With the relatively large brush, line variation is amazing, and you can bounce between extra thick and extra thin within a single stroke.
Pentel makes a damn good brush pen and this has held true across its various product lines.
As with other Pentel brushes with a reservoir, ink flow is variable depending on when you last squeezed that reservoir to push ink down to the pen section, though I did find ink flow to be harder to control here than in the Pentel Standard Brush. Maybe it’s the funny reservoir shape? It’s shorter and wider than the standard and oval-shaped, so it can lay flat on two sides.
The light black ink feels thinner and runnier than the standard brush’s standard black — this makes dry brushing difficult and extra thin lines harder to achieve, though you can still get pretty fine. The precision of the brush tip makes using the brush just for grey tone feel like a waste though.
At least for me, I tend to be pretty lazy when adding value to ink sketches. I don’t worry much about coloring in the lines, just slop on grey where I feel like it goes, and have a tendency to be much rougher with the brush tip (smashing it hard against the paper) when adding grey than when actually inking.
The Pentel Arts Aquash Pigment Ink Brush’s tip makes filling in small areas with grey very easy, but it may be overkill for filling larger and more general areas. On the other hand, it can be great for adding background elements with the same level of precision and detail as the primary inkwork.
As advertised, the ink in the Pentel Seiboku is reasonably water-resistant and holds up well against watercolor. The “light black” ink looks pretty black-black when compared to light watercolor washes, but this pen may still be a nice alternative to a “real black” ink brush pen if you want to use it alongside watercolor.
The ink in the pen is also alcohol-ink resistant and plays well with Copic markers.
The Pentel Arts Aquash Pigment Ink Brush is a nice pen with a horrible name — but it’s also kind of a weird product that doesn’t really fit anywhere, which is made extra obvious by its horrible name.
Grey ink (or “light black”) bristle-tip brush pens are rare and their use cases feel extremely narrow. It’s just too good of a pen for simply adding grey tone, but grey is a weird color to ink in (or to write in). What else is this pen for?
Pentel’s proprietary reservoir pen bodies are difficult to fill with your own inks, so if you want color variety, it makes a lot more sense to just get one of Pentel’s Color Brushes, though those don’t use water-resistant ink. The Color Brush reservoir refills aren’t supposed to be compatible with the Seiboku (since the reservoir shapes are different and screw in opposite ways), but can fit if you’re stubborn…
Meanwhile, the Color Brush refills are compatible with Pentel’s Standard Brush pens and the Color Brush Pigment Ink line (why is this line separate from the pen in this review??) which offer more options for tip sizes.
Most of the Pentel Standard Brushes and Color Brushes are also cheaper than the Pentel FRH-MN, which at $9.89 MSRP is still pretty reasonable for a pen of its caliber, but it doesn’t really make sense to get it when the other options are just as good and more versatile?
So yeah. Good pen, but there are better, less confusing options by Pentel. I’m not really sure why this pen even exists. ¯\_(ツ)_/¯