Permanent Fountain Pen Inks Explained: “Bulletproof,” “Document,” “Pigment,” “Iron Gall,” and more

If you're like me, you spend way too much time reading about waterproof/permanent fountain pen inks online

The problem: ink labels are marketing first, chemistry second

“Permanent,” “waterproof,” “archival,” “document,” “bulletproof,” “pigment,” “iron gall”… these terms get used inconsistently across brands and conversations on the Web, and they often describe a performance goal (survives water, or water and UV exposure, or specific chemicals commonly used in document forgery) rather than a formula or type of ink chemistry (pigment vs iron gall vs dye).

I've created a chart (scroll down to see it) to help you (and honestly, myself) translate the fountain pen ink labels you see into: what it likely is, what it’s good at, commonly associated risks, and which ink is right for your goals (and your specific fountain pens).


TL;DR: Which kind of "permanent" fountain pen ink is right for you?

 

  • Want good water and UV resistance, and a more traditional ink?
    Consider modern iron gall—great permanence with a manageable care routine. Especially good for many vintage and gold-nib pens. Cleaning less frequently is ok.

 

  • Need maximum permanence for official, financial, or legal documents?
    You need a certified document ink. Clean frequently.

 

  • Just want basic spill insurance for everyday journaling, with minimal cleaning hassle?
    Look for water-resistant inks (not necessarily “waterproof”), especially if you rotate pens a lot. Many people report going months (or even a year, with a good cap seal) between cleanings, with no issues. Regular, water-resistant dye inks are also easier to clean in case you do let them dry out in a pen.

 

If you're still not sure, just grab this ink - it's a fantastic, affordable, beautiful pigment ink that will work for 95% of what most people need, from addressing envelopes to writing field or lab notes that need to last decades:

Now let's dive into some high-level permanent fountain pen ink concepts that make the table I've created a bit easier to read.

TL;DR: High Level Permanent Fountain Pen Ink Concepts

If you just want the essential concepts you need to know about permanent or waterproof fountain pen ink:

  • Pigment and iron gall are the two most common chemistry families associated with true permanence. Pigment ink is composed of little particles that dry on (and in between) paper fibers. Iron gall is an ink traditionally made from the Oak Gall Nut, mixed with iron shavings, and stabilized with a strong acid: it basically rusts or burns the paper fibers, creating a permanent mark.

 

  • Words like Document and archival are performance claims (ideally backed by a an ISO certification which ensures that the ink meets these standards).
  • Words like permanent, water resistant, and waterproof are just marketing terms or casual descriptions of an ink's performance. I wouldn't trust them implicitly, because even normal water-soluble dye inks can occasionally be called "water resistant." I guess it depends on how much water you use!


Glossary / Translation Table

Here's a cheat sheet where I've added significantly more detail based on what I've learned during my fountain pen journey.

Label / Term What it usually means What it likely is (composition) Typical water performance Typical pen-care needs Best for Watch-outs / gotchas Example Ink(s)
Pigment ink “Permanent via particles” Pigment particles suspended in liquid (often with binders) Often very water-resistant once dry Higher: don’t let it dry out in pen; clean regularly Signatures, addressing, art linework, journaling you want to survive spills Can clog if neglected; some papers show “surface sitting” or smudge until fully set The entire Octopus Write & Draw line
Iron gall “Permanent by reaction” Dye + iron salts that oxidize/darken and bond over time, essentially rusting/burning into the paper Usually high permanence after it cures Moderate: more frequent cleaning than basic dye inks Gold-nib pens. Hard-to-clean pens. Many vintage pens. Can be lighter at first then darken; can cause wear on pens with non-gold metal parts that come in contact with ink. Platinum Lavender Black (one of my favorites), or Rohrer & Klingner Salix.
Document ink “Made for official records” Often pigment or a very water-resistant dye system Usually high, but varies Varies (often like pigment: regular cleaning) Legal/official notes, signing, work docs “Document” is not a chemistry; two brands can mean totally different things Rohrer & Klingner Dokumentus Green
Permanent ink “Hard to remove” Vague. Could be pigment, iron gall, or “enhanced” dye Anywhere from meh → excellent Varies Verify ink specifics so you know what you can trust it to do. “Permanent” might mean water-resistant but not lightfast; or vice versa (general marketing term)
Waterproof “Survives water exposure” Any formula claiming water resistance Usually good, but not guaranteed Varies Addressing envelopes, field notes Some inks are waterproof only once fully cured; some leave a readable “ghost” but bleed color (general marketing term)
Water-resistant “Some stays behind” Often dye-based with partial binding Partial (readable but washed) Low Everyday writing with occasional spill insurance Easy to overestimate—may feather/halo when wet Quick drip test; see if text remains crisp
Archival “Long-term stability” Varies; ideally high lightfastness + permanence Varies Varies Varies Often undefined; may be used loosely to mean "Document ink, but without the resistance to forgery chemicals" Prefer something certified as "document ink" at Bottle and plume, like Octopus Fluids Document Black
Lightfast “Resists fading in light” Could be any ink chemistry Not necessarily waterproof Varies Displayed writing/art, labels, sketchbooks Lightfast ≠ waterproof; you might get one without the other
Forgery-resistant “Harder to alter” (marketing term) Could be any ink chemistry Often high Varies Checks, official notes Marketing claim—verify with bleach/solvent tests. Prefer an officially certified DIN ISO-12757-2 document ink for important documents.
“Bulletproof” Noodler's Brand term: “bonds to paper / resists many kinds of tampering” I think this is a cellulose-binding dye system (other brands using this term may mean something else with it) High Usually moderate Non-critical documents that you want to survive for decades. Lacks the chemical resistance + third-party claim certification of document inks. Performance varies by ink. Noodler's bulletproof black
Nanopigment / nano Marketing term: “Very fine pigments” Pigment ink, with smaller particles that are more likely to stay suspended before going down on paper. High Similar to pigment inks: regular cleaning Clean, permanent everyday writing Still pigment: don’t let it dry in pen







 

 

How to Test Ink Water Resistance Yourself

If you're unsure about an ink (or even the specific batch you got), just test it for yourself! Here's a fun video of me doing just that:

  1. Dry-time water test: write a few lines and test at 1 minute, 10 minutes, and 24 hours (drip water, wait 10 seconds, blot).
  2. Rub test: after it’s dry, rub with a slightly damp fingertip or cotton swab. If it smears easily, it’s not the permanence you think it is.

 

Fountain-pen care rules for all permanent inks (the non-negotiables)

  • Don’t let permanent inks dry out in the pen. If you won’t use it for a while, flush it.
  • Clean on a schedule: more often for pigment/document, moderately often for iron gall, less often for standard dye inks.
  • Use pens with good cap seals if you’re using pigment/document inks regularly. If you're looking for a pen with an amazing cap seal and a no-brainer pricetag, try a Platinum Plaisir:

I hope that's been helpful! Feel free to write with feedback or additional info if I missed anything.

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