Here are a couple of simple water tests on Borealis Black.

Running water test = 30 seconds under the cold tap. (It's summer in Texas, and we don't really have "cold" water out of the "cold" tap -- more like "warm".) As you can see, the ink spreads out a little bit (all three samples were done with the same Preppy pen). It also spreads to soak through the paper (Levenger legal pad). On the unsoaked sample, you can't see any soak through on the back of the sheet.

Soak test = 4 hours in a cup of water, then 1 minute in the microwave to boil the water. During the cold soak, the ink spread out a bit, soaked through to the back of the paper, faded a bit, and as you may be able to see, also spread down the paper toward the bottom of the cup. During the microwaving, it faded a bit more.

What you can't see (because this is a black and white scan) is that Borealis Black has a bit of green in it. The Running Water sample and the Soak sample both turned a kind of greenish gray. This is a black and white scan because I couldn't get the color adjusted on the color scan to where it was an accurate depiction of what I see on the paper. I want to emphasize that the greenish color is very subtle. I did a filter paper chromatography test too, but again could not get the color to come out right, so I'm not uploading it. There was the slightest halo of a bluish-green color around the blackest black center of the sample. When you write with Borealis Black using a broad nib, you can see a glint of green on top of the ink. It is a great deal like the way I remember Skrip and Quink Black looking back 50 years ago.

So the bottom line is, use Borealis Black for your letters and envelopes without fear of water. It won't hurt them. I don't have any way to test for UV or sunlight resistance, so better take Nathan's word for it that this ink will fade with time. So you might not want to pen anything archival with it.

Borealis Black water tests

Here is the direct image:

Bill,

Very useful and interesting. Bulletproof not necessarily so important as drying speed! Thanks.

You're welcome. In many ways, Borealis is the ideal black ink for any application other than those uses requiring bulletproof resistance to alteration, or those requiring archival permanence. At least it is for me.

Bill, it's so great you're back on FPN and contributing to the general pot of collective knowledge.

But sure, Bill, you can test for UV resistance: cut a sheet in half and put one side up on a windowsill for about three weeks; you've got all that super Texas sunshine!! Keep the other half in the drawer.

I live in a house with deep eaves and big trees. Does wonders for keeping my electricity bills down in the summer, but it means I have no sunny windowsills.

Thanks!