The Pentel Aquash watercolor brush.

The Pentel Pocket Brush Pen has a fanatical following among artists. It has a springy, responsive brush that can do hairlines and fat strokes. The ink is waterproof black, and comes in cartridges. Pentel also makes Pentel Aquash, the waterbrush that made watercolor painting urban-friendly. Waterbrushes hold water in the barrel so artists on the go don’t court spilling disasters. The Pentel Aquash comes on its own, or as part of a portable watercolor set.

When you put the two together, you get the Pentel Aquash Watercolor Brush.

Pentel Aquash watercolor brush
Pentel Aquash watercolor brush

The barrel is the cartridge. The ink is light black, and waterproof. It reminds me of diluted sumi ink, especially when applied in layers.

Pentel family shot
Pentel family shot

The Pocket Brush pen and the Aquash have very different brush tips. The Aquash has a fuller base, and overall is larger.

Pentel Pocket Brush pen and Aquash Watercolor brush
Pentel Pocket Brush pen and Aquash Watercolor brush

The Pocket brush feels like it has thicker ink. The Aquash with Light Black pigment ink feels more watery.

Comparison
Comparison

Here’s how it looks bare, then with watercolor added.

"Why isn't he DM'ing me yet?"
"Why isn't he DM'ing me yet?"
"Oh, he's not on Twitter."
"Oh, he's not on Twitter."

I really like the change from strong black outlines. I used a Pentel Aquash waterbrush to apply the watercolor. Because they’re the same body shape, my hand wasn’t jarred from its rhythm, the way it usually feels when I switch between – let’s say – the Pocket Brush pen and a regular watercolor brush with a thin handle.