*the above drawing dried overnight before I went back to add watercolors on site*

Waterproof means the ink-paper doesn’t change the qualities,
as long as you let them dry (which is true for water-resistance too.)
The ones I use dry fast enough — I let them sit about a half hour with normal linework.

I consider the ones below waterproof because I’ve tested them myself, and never had a failure (again, if they were dry), are below.

DeAtramentis Document Ink (DeaDoc)

This is a favorite waterproof ink.  There are many color, and they mix nicely.
I recently added Urban Grey to the collection and intend to try Urban Sienna.
The only ink I would never ever put in a fountain pen is their White ink.

Vanness has the best selection but you have to search for waterproof.

I go through bottles of this ink!

Super5 Ink

I adore these inks!  I love their slightly “off” colors — not crayola crayon colors!
I use them more than the DeaDoc inks except for the black,
because I like the effect of the slightly off colors with my watercolors.
I can find all the colors at Blue Rooster Art store in Los Angeles but they ship!
Wet Paint Art carries a few colors… one thing I am disappointed in is that they changed their packaging to a smaller bottle (30ml) but the price went up!

SketchINK

There are many lovely colors, and all my tests show they are waterproof.
I don’t personally like them due to a chemical smell,
but I have one I use because it is a beautiful clear blue.
Vanness carries all of them.

Platinum Carbon Black

I always have a Platinum Carbon Pen with Platinum Carbon ink waterproof cartridges….
I use it all the time!  It is not a BLACK-black because it has a silver sheen which I sometimes don’t want in a more formal watercolor. Dries super fast as linework!

I have heard others mentioned I’ve not tried but here is my advice:
I strongly suggest that an artist try them on every new paper
they will be doing watercolor on before they use them in a drawing —
and I do this even with my favorites when I have a different brand of sketchbook.

Noodler’s

I include them here because so many people talk about them as waterproof, and all six I bought moved on many papers, like the image at the top of the page.I am willing to use Noodler’s Lexington Grey
in grisaille work (shadow under watercolor, shown right) because I have a huge droppered bottle, it is a nice grey,  and the little bit it moves doesn’t effect my
watercolor — but I never use it for linework because on some papers I’ve had it move.

Water RESISTANT

Water Soluble

And of course, I use water soluble inks (below are some favorites)
all the time to make sketches moving the ink as I love to do!

one of robert oster’s browns…

robert oster blue sea

diamine chocolate

btw, not platinum citrus but a mix of robert oster

This is the end of my productive rant!