Ink
Waterproof fountain pen ink
Ordinary ink dissolves the moment a wet glass lands on the page. Three chemistries resist it, and each charges you something different for the privilege.
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Almost every fountain pen ink you can buy is a dye dissolved in water. That is why it flows well, why it cleans out easily, and why a spilled drink turns a page of it into a blue smear.
If the writing needs to survive water — an address on an envelope, a signature, a field notebook, ink drawing you intend to paint over — you need a different chemistry, and there are only three worth knowing about.
The three that work, and how they differ
| Type | How it resists water | What it costs you |
|---|---|---|
| Pigment | Solid particles too large to wash away once the carrier dries | The most cleaning. Dries hard in a pen left standing. |
| Bonding dye | The dye chemically attaches to the paper's cellulose fibers | Harder to flush out than an ordinary dye. |
| Document / archive dye | A formulation designed to resist running, without solid pigment | Less cleaning than pigment, and a weaker claim. |
| Ordinary dye | It does not | Nothing — and it will not survive a spill. |
That table is the whole decision. Pigment is the strongest claim and the highest maintenance. Document inks sit in the middle. A bonding dye like Noodler's is the interesting hybrid: it resists water well while behaving more like an ordinary ink in the pen.
Quick picks
Ranked for the beginner buying their first setup. Every pick names who it is wrong for.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 |  Platinum Carbon Black, 60 ml A true pigment ink: the blackest line you can get out of a fountain pen, and permanent once dry. | Line work and archival notes | |
| 2 |  Noodler's Black, 3 oz A dye that bonds to paper fibers, so once it is dry the writing stays put even when the page does not. | Writing that has to survive water | $18.50 · View on Amazon #ad Price as of October 21, 2026. How this is funded |
| 3 |  Sailor Pigment Ultra Black, 50 ml Sailor's pigment black in a bottle, and the direct alternative to Platinum Carbon if you want permanence without buying into Platinum. | Pigment permanence from the third Japanese house | $17.99 · View on Amazon #ad Price as of October 21, 2026. How this is funded |
| 4 |  De Atramentis Document Black cartridges, 5-pack The same document-grade black as the bottle, in a standard international cartridge — which makes it the one waterproof cartridge here that is not tied to a single pen brand. | Waterproof ink in a cartridge that fits most pens | $7.95 · View on Amazon #ad Price as of October 21, 2026. How this is funded |
| 5 |  Platinum Carbon Black cartridges The same permanent carbon ink as the bottle, in a cartridge, for a Preppy or Plaisir you actually carry. | Pigment ink without a bottle | $5.10 · View on Amazon #ad Price as of October 21, 2026. How this is funded |
1. Line work and archival notes
Platinum Carbon Black, 60 ml
A true pigment ink: the blackest line you can get out of a fountain pen, and permanent once dry.
Pigment ink suspends solid particles rather than dissolving a dye, which is why it is opaque, why it is permanent, and why it will clog a pen left to dry out.
For drawing, for signatures, and for anything you want legible in twenty years, nothing else in a fountain pen comes close.
It demands discipline. Do not leave it in a pen you are not using, and flush thoroughly when you change ink.
| Format | 60 ml bottleSource: Platinum Carbon Black (retail listing, read 2026-09-01) |
|---|---|
| Type | Pigment ink (carbon), not a dyeSource: Platinum Carbon Black (retail listing, read 2026-09-01) |
| Also sold as | Platinum Carbon cartridges, for pens that take themSource: Platinum Carbon ink cartridges (retail listing, read 2026-09-01) |
| Published drying time | Not published |
What it does well
- Genuinely black and genuinely permanent
- Excellent for ink drawing over watercolor
- Available as cartridges as well as a bottle
What it does not
- Will clog a pen that is left to dry
- Needs more frequent cleaning than any dye ink
- Not a good match for a pen you use once a fortnight
Skip this if your pen sits unused for weeks at a time — a dried pigment ink is a much bigger problem than a dried dye ink.
2. Writing that has to survive water
Noodler's Black, 3 oz
A dye that bonds to paper fibers, so once it is dry the writing stays put even when the page does not.
#ad Price as of October 21, 2026. How this is funded
The reason to keep a bottle of this is not the color. It is that a signed document, an address on an envelope or a note left on a windowsill survives contact with water, which ordinary dye inks do not.
Because the dye bonds to the paper rather than sitting on it, it also tends to feather less on cheap stock than its wetness would suggest.
The trade-off is cleaning. Inks that bond to cellulose also bond to the inside of a pen, so flush more often and do not leave it sitting in a pen you plan to ignore for a month.
| Format | 3 oz bottleSource: Noodler's Black (retail listing, read 2026-09-01) |
|---|---|
| Type | Waterproof once dried; the maker describes the dye as bonding to celluloseSource: Noodler's Black (retail listing, read 2026-09-01) |
| Claimed behavior | Feathering-resistant and quick-dryingThe maker's own claim on the listing. We have not tested it.Source: Noodler's Black (retail listing, read 2026-09-01) |
| Published drying time in seconds | Not published |
What it does well
- Water resistance that ordinary dye inks cannot offer
- Large bottle
- Copes better than most wet inks on ordinary paper
What it does not
- Harder to flush out than a standard dye ink
- Not for a pen you will leave unused for long periods
- No published drying figure despite the quick-drying claim
Skip this if you swap colors often or leave pens inked for weeks — a bonding ink punishes both habits.
3. Pigment permanence from the third Japanese house
Sailor Pigment Ultra Black, 50 ml
Sailor's pigment black in a bottle, and the direct alternative to Platinum Carbon if you want permanence without buying into Platinum.
#ad Price as of October 21, 2026. How this is funded
Pigment inks suspend solid particles rather than dissolving a dye, which is what makes them opaque, permanent and water resistant once dry. Sailor is one of only a handful of makers producing one for fountain pens at all.
It exists on this site as the alternative to Platinum Carbon Black. Both are pigment blacks; which you buy is mostly a question of which cartridge system you are already in, since the cartridge versions are not interchangeable.
Like every pigment ink it demands more cleaning than a dye. Keep it in a pen you use, and flush it properly when you change.
| Format | 50 ml bottleSource: Sailor Pigment Ultra Black (retail listing, read 2026-09-01) |
|---|---|
| Type | Pigment inkSource: Sailor Pigment Ultra Black (retail listing, read 2026-09-01) |
| Also sold as | Kiwa-Guro pigment cartridges, 12 to a packSource: Sailor Kiwa-Guro cartridges (retail listing, read 2026-09-01) |
| Published drying time | Not published |
What it does well
- Genuine pigment permanence and water resistance
- Available in cartridges as well as a bottle
- A second option in a category with very few products
What it does not
- Will clog a pen left standing, like all pigment inks
- Sailor's cartridge is proprietary to Sailor pens
- No published drying or water-resistance figures
Skip this if you already own Platinum Carbon Black — they do the same job, and owning two pigment blacks helps nobody.
4. Waterproof ink in a cartridge that fits most pens
De Atramentis Document Black cartridges, 5-pack
The same document-grade black as the bottle, in a standard international cartridge — which makes it the one waterproof cartridge here that is not tied to a single pen brand.
#ad Price as of October 21, 2026. How this is funded
The Document range occupies the middle ground in waterproof ink: more resistant than an ordinary dye, less demanding than a pigment. That matters because pigment inks are the usual answer to water resistance and they punish a pen that sits unused.
The useful difference here is fitment. The other waterproof cartridges on this page fit one brand of pen each; this is a standard international cartridge, so it fits most pens that take one. The listing is explicit about the exception: pens that accept only their own maker's cartridges, which it names as LAMY, Parker, Platinum and Waterman.
What the maker still does not publish is a number. Heat, light and water resistant is a claim with no standard behind it, and water resistance is the entire reason to buy this ink, so treat it as the maker's word rather than as a measured property.
| Format | Standard international cartridges, five per packSource: De Atramentis Document Black cartridges (retail listing, read 2026-10-10) |
|---|---|
| Maker's resistance claim | Document quality; heat, light and water resistantThe maker's own wording. It is a claim rather than a figure — no standard or test is cited, which is why we do not restate it as a finding.Source: De Atramentis Document Black cartridges (retail listing, read 2026-10-10) |
| Fitment | Any pen taking a standard international cartridge; will NOT fit pens that take only their own maker's cartridges, such as LAMY, Parker, Platinum and WatermanSource: De Atramentis Document Black cartridges (retail listing, read 2026-10-10) |
| Range | Document range, sold alongside a separate Archive rangeSource: De Atramentis Archive Ink Black (retail listing, read 2026-10-10) |
| Published drying time | Not published |
What it does well
- Water resistance without suspended pigment particles
- Fits most pens that take a standard international cartridge
- No bottle to flush, and the Document range covers other colors
What it does not
- The resistance claim carries no figure or standard behind it
- Will not fit a LAMY, Parker, Platinum or Waterman that takes only its own cartridges
- Five cartridges is far less ink than a bottle
Skip this if you need archival permanence for something that matters — a pigment ink is the stronger claim, and it is the one to use when the document has to last.
5. Pigment ink without a bottle
Platinum Carbon Black cartridges
The same permanent carbon ink as the bottle, in a cartridge, for a Preppy or Plaisir you actually carry.
#ad Price as of October 21, 2026. How this is funded
A pigment ink in cartridge form is genuinely useful: you get permanence without owning a bottle, and a Preppy with its slip-and-seal cap is unusually well suited to holding one.
The cleaning discipline still applies. Pigment dries hard, and a pen left inked and unused for a month is a cleaning job.
These are Platinum's proprietary size, so they fit Platinum pens only.
| Format | Platinum proprietary cartridges, blackSource: Platinum Carbon ink cartridges (retail listing, read 2026-09-01) |
|---|---|
| Type | Pigment ink, the cartridge form of Platinum Carbon BlackSource: Platinum Carbon Black bottle (retail listing, read 2026-09-01) |
| Published drying time | Not published |
| Published water resistance | Not published |
What it does well
- Permanent, water-resistant writing with no bottle needed
- Pairs well with Platinum's drying-resistant cap design
- Convenient for carrying
What it does not
- Proprietary to Platinum pens
- Needs more frequent flushing than dye ink
- Small capacity per cartridge
Skip this if your pen is not a Platinum, or if it regularly sits unused for weeks.
What nobody publishes, and why that matters here
Not one of the inks on this page carries a published water-resistance rating. No maker states how long the writing survives immersion, or in what conditions, or against what standard. Several describe their ink as waterproof or document-grade; none quantifies it.
That is worth stating loudly on this page in particular, because water resistance is the only reason to buy any of these. We can tell you the chemistry each ink uses and what its maker claims, and we mark the numeric rows "not published" rather than inventing a figure. The reasoning is on how we choose.
The cleaning cost is real
Pigment ink suspends solid particles. Those particles are what make the line permanent, and they are also what blocks a feed if you leave the pen unused for a month.
The practical rules are simple and not optional: keep pigment ink in a pen you use weekly, flush it every two to three weeks rather than every two months, and never store a pen with pigment ink sitting in it. How to clean a fountain pen has the routine, and a badly clogged pen usually recovers with an overnight soak in cool water.
Waterproof for drawing
If you are laying watercolor over ink lines, pigment is the only safe answer. A dye ink — bonding or otherwise — will lift when a wet brush passes over it, and a document ink is not a strong enough claim to risk a finished drawing on.
There is one thing to un-learn here: this is the single case on the site where we would steer you away from the coated paper we normally recommend. Hard-sized coated stock repels a watercolor wash as effectively as it repels ink bleed. Use uncoated, heavier paper instead, and see pens for drawing for the nib to pair with it.
What not to put in a fountain pen
- India ink and most drawing inks. They contain shellac or heavy pigments that set solid inside a feed. Waterproof, and a pen you will not recover.
- Calligraphy dip-pen ink. Same problem — it is formulated for a nib you can wash under a tap, not a feed with capillary channels.
- Iron gall inks, as a first waterproof purchase. Genuinely permanent and genuinely capable of corroding a nib left standing. Not where to start.
The rule is narrow and worth keeping: use ink sold specifically for fountain pens, and if you need permanence, use a fountain-pen pigment ink rather than an art-store bottle.
Do you actually need it?
Often, no. For a journal that lives closed on a shelf, an ordinary dye ink will outlast you, and the inks for journaling page covers that case properly.
Buy waterproof for the specific things that need it — addresses, signatures, forms, field notes, drawing — and keep an ordinary ink for everything else. Owning one bottle of pigment black covers the whole category for most people, and the black ink page is where to choose it. If you want the same permanence in blue, the blue ink page covers the pigment option and why blue-black alone is not enough. If the reason is travel, the travel journals page explains why changing the ink beats buying a waterproof notebook.
Questions people actually ask
Is fountain pen ink waterproof?
Ordinary fountain pen ink is not — it is a dye dissolved in water and it runs on contact. Pigment inks, bonding dyes such as Noodler's, and document-grade inks resist water; everything else does not.
What is the most waterproof fountain pen ink?
A pigment ink such as Platinum Carbon Black or Sailor's pigment black. The solid particles cannot wash away once the carrier dries. No maker publishes a water-resistance rating, so we do not rank them numerically.
Will waterproof ink ruin my fountain pen?
Only if you leave it to dry in the pen. Pigment ink dries hard, so keep it in a pen you use weekly and flush every two to three weeks — see how to clean a fountain pen.
Can I use India ink in a fountain pen?
No. India ink and most drawing inks contain shellac or heavy pigments that set solid inside the feed. Use a fountain-pen pigment ink instead if you need permanence.
What waterproof ink should I use for watercolor?
A pigment ink. A dye will lift when a wet brush passes over it, no matter how water-resistant it claims to be. Use uncoated paper too — coated stock repels a wash.
Is Noodler's Black waterproof?
Its maker describes it as waterproof once dried, and explains the mechanism as a dye that bonds to cellulose. That is the maker's claim, cited on the product entry above; no quantified figure is published by anyone.
Sources
- Platinum Carbon Black, 60 ml (retail listing, read 2026-09-01)
- Noodler's Black (retail listing, read 2026-09-01)
- Sailor Pigment Ultra Black, 50 ml (retail listing, read 2026-09-01)
- De Atramentis Document Black cartridges (retail listing, read 2026-10-10)
- Platinum Carbon ink cartridges (retail listing, read 2026-09-01)
- Sailor Kiwa-Guro pigment cartridges (retail listing, read 2026-09-01)