Diamine Emerald is another somewhat muted green, but warmer than Diamine Umber. I actually saw yellow tones where the shading is light. I tested Emerald on both the Clairefontaine Unplugged Staplebound Duo and G Lalo off-white, using a Pelikan m215 with Binder Italifine nib, which has a 0.9mm cursive italic on the front side and fine round tip on the backside of the nib.
The flow is slightly less lubricated, IMO, than Diamine Umber, but not uncomfortably so.
Below are a couple images of Emerald on the G Lalo paper, which minimizes the color differences between Emerald and Umber.
In the image below, one can see the color differences when using both a wide and narrow nib. The shading is also evident. Like the Umber, there is some shading, but not tons. I think dry times were a tiny bit better in Emerald than in Umber, but not enough to make any significant different. The same can be said about it’s water resistance.
Here is a comparison shot showing both Umber (on the left) and Emerald (on the right) on the G Lalo paper. Though the off-white paper makes their color tone differences less obvious, I can still see it when they are next to each other.
Performance-wise, I think Umber has a slight advantage, because it lays down a slightly smoother line. Again, it’s not enough of a difference to make a big deal over, but I noticed it on these papers. Color-wise, I prefer warmer tones of the Emerald, but I like the darker tone of the Umber. The lighter tone of the Emerald in finer nibs is actually a bit too light for me to use regularly.