Once you get past the Iron Gall archival aspect of this ink, there are only a couple of other things to consider when using it. For one, you might be surprised when the ink dries either the same shade as when it's wet, and (in some cases) it actually dries darker. Most inks become lighter as they dry, which can diminish some of the original pop of the ink color. Not so with the Green #4. It stays the nice medium-green color and dries a bit darker in the wetter spots.
The other thing to remember when using an Iron Gall ink is that it should not stay in your pen for long periods without being used. To me, I don't view this any differently than other inks, in so much that I like to clean out pens if they've been unused after about a month. If you're mindful about how long the ink has been in your pen, you should be fine. However, if the pen you're using has special sentimental value, or is difficult to replace, you might be a bit more careful about keeping it clean. Either way, these KWZ inks are fairly gentle, and I've never had an issue with pens getting clogged or becoming difficult to clean.
Now, after those differences, the Green #4 acts just like any other ink. The color is a wonderful woodland green with brown hints and a very subtle gold shimmer in certain lights. I wasn't really sure about the color when I first started using it, but I grew to love it because it has an abundance of character.
The shading is a large part of that character, along with the subtle shimmering effect. The shading isn't dramatic, but it's definitely noticeable in nibs from the F size and higher (German standard). It's a perfect amount of flare for the color.
