I tested this ink in a Noodler's Flex pen and in retrospect I'm not sure this was a great idea. Perhaps I should have used it in a normal pen, to better gauge its abilities. The flex pen is too freely flowing and it may have warped some of my impressions.
Bottle
Hunter Green is one of the few inks in Noodler's lineup that come in tiny, 1oz (30ml) bottles, as opposed to the regular-sized 3oz (90ml) ones. While the price remains $13.50 per bottle, you're now paying 3 times as much, at $0.45 per milliliter. Is it worth it? Depends if you like what it has to offer.
Color and saturation
I can't help comparing this ink to Gruene Cactus Eel which was the first green ink I tested (of which I own a bottle). The color and saturation are very close and I would suspect that someone without a lot of experience with the two inks might mistake one for the other if they saw them on paper. Side by side, Hunter is lighter than Gruene Cactus but these two inks look like they came from the same mother.
One thing that really does differentiate them is the opacity of the two inks. While Gruene Cactus is clear (but dark), Hunter Green is opaque and milky. As a result, it is highly advisable to shake the bottle well before use. It also coated the insides of the plastic sample vial rather well. So in many ways it feels like paint. Don't be alarmed though, I highly doubt it can - or will - clog your fountain pen, unless you leave it sitting for ages. But that's valid for any ink in general.
One thing I should mention is that it was rather hard to clean the fountain pen after I had used it. I flushed the pen what seemed like a million times until the last trace of green was gone.
I must admit that I was taken aback by the name. "Hunter" suggests a darker shade of green, perhaps a little towards khaki. Well, this green is a tad too bright to be worn by a hunter as camouflage, I can tell you that.
This ink is well saturated and works well enough in a flex pen, although I remain convinced that I should have used a regular fountain pen to test it. A pen using this ink will produce a crispy, contrasty, well-defined line. As such, it can be a good match for a Sailor HighAce Neo's fine nib. Incidentally, that was the pen in which I tested Gruene Cactus.
Shading
There is no shading I can discern on photocopy paper, even with the dip pen or the flex pen. This green looks rather flat on cheap paper. On Rhodia 90g I believe I can see some highlights and shadows. My theory is that on cheap paper the ink is absorbed quickly but on the thicker, shinier paper it has time to pool up a little, thus drying up non-uniformly, which results in lighter and darker areas.
Feathering
On the cheap photocopy paper there is very little feathering and only when thick gobs of ink are deposited by the flex pen. Thinner lines don't feather at all.
Bleedthrough
Same as with feathering, thanks to the flex nib, the ink does manage to get through the photocopier paper. Thin lines on photocopy paper - likewise. I do suspect the flex pen had a role to play in this, even if I didn't press hard for the thin lines. On Rhodia's superior 80-gram paper the situation is much improved. There is some very slight ghosting on the reverse which gives you a hint that something is written on the other side, but it remains completely usable.
Flow and lubrication
Now this is a tricky subject. Since I used the flex pen, it's hard to determine how this ink would behave in a regular fountain pen. I adjusted my flex pen for extra flow and the ink certainly behaved well enough at that setting. As you can see from the samples, there is occasionally some railroading but that's neither the pen's, not the ink's fault. I think it's a testament of my inability with the flex nib.
Drying time
Hunter Green's drying times were short (less than 10 seconds) on cheap paper, perhaps because it gets absorbed quickly. On Rhodia 80g, I noticed the opposite: after 30 seconds the ink was still smearing. Notice that for the Rhodia test I didn't flex the nib much so it essentially acted as a fine.
Smearing when dry
None!
Water resistance
Here's where Noodler's Hunter Green surprised me. I had no idea that this ink was waterproof. Not only that, but the ink is in fact part of Noodler's bulletproof series. I guess I suspected that in the back of my head but I wasn't consciously aware of it. As such, this ink becomes permanent on paper, although some of its components are washed off when watered, creating a faint light green halo around the lines. Though I failed to write down the time I exposed it to water, it was actually 1 minute under the tap.
Conclusion
Noodler's Hunter Green is an ink that doesn't come cheap but its premium price could be justified by some of its features. Its fairly cheerful color might not be particularly well suited to a business setting but that depends on your line of work. For casual writing or a diary it should be a lot of fun. I don't really recommend using it in a flex pen because of its lack of shading but it is dark and crisp enough that it should work well with very fine nibs. If I'm not mistaken, this is one of the few (perhaps the only) bulletproof inks on the market in this particular shade of green. Other waterproof greens are either too dark, too light or too drab. If this is the color you fancy and you need it to be resistant to forgery, this might be the very ink for you.
Here are the two samples I wrote on common photocopier paper and Rhodia 80g paper, with the mention that this ink was a bit hard to photograph and post-process. I'm not sure the representation is 100% accurate and it may vary from monitor to monitor.
