Robert Oster Green Black aka Grun-schwarz is a dark wintery green. You can find this ink for sale at most retailers including Pen Chalet (aff. link) and Vanness Pens.

Swabs:

In large swabs on Tomoe River paper the ink looks slightly blue with a little bit of black sheen.

Writing samples:

Let's take a look at how the ink behaves on fountain pen friendly papers: Rhodia, Tomoe River, and Leuchtturm.

Dry time: 15 seconds

Water resistance: Medium

Feathering: None

Show through: Medium

Bleeding: Low

On Staples 24 lb copy paper there was some feathering in all nib sizes.

Green Black is closest to Pilot Iroshizuku Hoteison. Click here to see the Robert Oster inks together, and click here to see the green inks together.

I used a Franklin-Christoph 46 Blue Diamondcast with a broad nib on a Taroko Enigma notebook. The ink had an average flow.

Overall, it’s a well-behaved dark green. This ink would be great for an office appropriate green or for the dark winter months.

Disclaimer: All photos and opinions are my own. This page does contain affiliate links but this post is not sponsored in any way.