I used KWZ Iron Gall Green #1 in a Pelikan with fine nib and in a Lamy Al-Star with broad nib. Flow is on the dry side. The Pelikan was a great match: in this wetter pen, Iron Gall Green #1 had perfect startup and flow, even when left unused for a few days.
The Lamy is a drier pen, and I would see a slight hesitation on startup there — the first down-stroke could be a little dry and patchy at the beginning of the day. But after that it felt very lubricated and flowed without interruption, albeit on the dry side.
As a corollary, the dryness of Iron Gall Green #1 meant it behaved very well on poor paper. I didn’t see any feathering or bleedthrough, and only a tiny bit of showthrough even with the Lamy broad nib. Here is Iron Gall Green #1 on Staples Sustainable Earth, which is a more absorbent and feather-prone paper.
Actually, on the lower quality paper, I thought the dry Al-Star nib wrote better than on smoother fountain-pen friendly paper.
I really liked the the gorgeous shading of Iron Gall #1. Here it is in the Pelikan on Rhodia.
The blue-green color can probably be best appreciated from the Lamy broad nib, because you see more of it.
Here it is on cream-colored Tomoe River paper.
Iron Gall Green #1 had very good water resistance, as one would expect from an iron gall ink, even on smooth fountain-pen friendly paper.
Yet it cleaned up from my pens extremely easily. I have come to expect that from KWZ inks by now, but it’s still great to see an iron gall ink that cleans up with just a little flushing with water. I had KWZ Iron Gall Green #1 in the Pelikan Toledo for several weeks, and it cleaned up with hardly any work at all.
I don’t have any inks that are the exact color of Iron Gall Green #1. For context, here it is between Kaweco Palm Green on the left, which is a fairly pure medium green, and Diamine Tropical Green on the right, which is a favorite blue-leaning green of mine.
Iron Gall Green #1’s blue tint really stands out, even compared to Diamine Tropical Green.
Here it is between Pilot Iroshizuku Shin-ryoku on the left and Diamine Tropical Green on the right.
Finally, here is Iron Gall Green #1 next to another dark green KWZ ink, this one Foggy Green, which I reviewed here.
Paper towel chromatography of Iron Gall Green #1 is below. The source of its lively blue tint is quite apparent.
I received this sample of Iron Gall Green #1 from KWZ Ink so I could review it. KWZ Ink is available online from at least one US store and also directly from KWZ in Poland. KWZ’s website contains excellent information about using and cleaning out iron gall inks.