So is the Noodlers Bulletproof Black Ink waterproof? The answer is complicated.
These are the paper I've tested the ink on:
- Daler Rowney Aquafine watercolour paper
- Daler Rowney Aquafine watercolour paper 2nd test
- Canson XL watercolour paper
- Fabriano Studio 25% cotton watercolour paper
- Arches 100% cotton watercolour paper
- Leda Art Supply sketchbook
- Strathmore Writing paper 25% cotton
I dried the ink for a few minutes with a hairdryer. When the ink is no longer glistening, I consider them dry.
Looking at the results, I don't really have any conclusive answer. How waterproof the ink is depends on the paper you use, and how you use the ink.
With the first Daler Rowney paper test, I wrote heavily and deposited a lot of ink. Even though the ink looked dry, it wasn't dry. My guess is there is so much ink that some of the ink is not in contact with the paper, hence some ink can still be washed off. That's why I did the second Dalery Rowney test with thinner strokes, and in that case it did seem like it's waterproof or water resistant.
For the Canson watercolour paper, it looks quite waterproof. Some ink did came off but it's not a big deal. The lines were still a bit thick so some ink may not have been in contact with the paper.
Fabriano Studio watercolour paper fared the worst. My guess is the paper is sized in a way that prevents the ink from being absorbed. I read that this ink is only waterproof on cellulose paper.
But this watercolour sketch above was painted on Fabriano Studio paper as well. This is coldpress while the small piece of paper above is hotpress.
The ink on Arches watercolour paper isn't that water resistant too. Arches paper is quite dry and I wasn't able to get a lot of ink on it, and even so, the ink wasn't water resistant.
The paper in Leda Art Supply sketchbook has no cotton content and the ink looks quite waterproof. Same result with the 25% cotton content Strathmore writing paper.
So whether or not the paper has cotton content doesn't seem to matter. How the paper is made is probably very important too. With some watercolour paper, the ink is waterproof but with others it's not.
Here's a sketch I drew on the Strathmore 400 series watercolour journal (0% cotton paper).
I left the sketch to dry overnight and the next day, the ink still smear on the opposite page.
This ink just takes a long time to dry. And even when it looks dry, it may not be 100% dry and waterproof.
So my overall recommendation is, always test the ink before you use it to create actual artwork or paint watercolour on it. There are so many different types of paper out there. There's no way to know how this ink will perform without first testing it on the paper.