Fountain Pen Ink Guide: Types, Properties, and How to Pick

Ink is where fountain pen writing becomes personal. The right ink turns a functional tool into an expressive one; the wrong one can clog your pen, feather across your paper, or simply disappoint. This guide covers the main ink types, the properties that matter, and how to choose between them.

The Three Main Ink Types

Dye-Based Inks

The most common fountain pen ink. Dye-based inks use soluble colorants dissolved in a water-based solution. They flow freely, clean up easily, and come in the widest range of colors.

• Pros: Excellent flow, easy maintenance, huge color variety, widely available, safe for all pen materials.
• Cons: Not waterproof — most will smear or wash out if the page gets wet. Some fade over time with light exposure.
• Best for: Everyday writing, journaling, note-taking, and anyone new to fountain pens.

Iron Gall Inks

One of the oldest ink formulations in existence, iron gall inks are made from tannic acid and iron salts. They start as a light gray-blue and darken to a rich, permanent black or brown as they oxidize on the page.

• Pros: Highly water-resistant once dry. Excellent archival permanence. Distinctive character — the ink looks different on the page than in the bottle.
• Cons: Mildly acidic, so it needs regular cleaning and shouldn't be left to dry in the pen. Modern formulations are gentle enough for most current pens; use extra caution with vintage pens, where older materials are harder to replace.
• Best for: Documents, correspondence, and writers who want permanence. Clean your pen every 2–4 weeks minimum.

Pigment Inks

Pigment inks use solid color particles suspended in solution rather than dissolved dyes. The particles sit on top of the paper rather than soaking in, which is what makes them waterproof and fade-resistant.

• Pros: Waterproof, archival, and highly lightfast. Excellent for documents and artwork.
• Cons: Can clog pens if left to dry in the feed. Require more frequent cleaning. Not suitable for all pen designs.
• Best for: Archival writing, sketching, and users who clean their pens regularly. Avoid in pens with complex filling systems.

Ink Properties to Know

Beyond ink type, a few key properties determine how an ink behaves on the page.

Water Resistance

Most dye-based inks are not water-resistant. If permanence matters — for contracts, important notes, or anything that might get wet — choose an iron gall or pigment ink, or look for dye-based inks specifically marketed as water-resistant.

Shading

Shading refers to the variation in color intensity within a single stroke — darker where ink pools at the start and end of a stroke, lighter in the middle. Shading inks are prized for the depth and character they add to handwriting. They perform best on smooth, well-sized paper that lets the ink pool slightly before absorbing.

Sheen

Sheen is a secondary color that appears on the surface of dried ink under certain lighting — a red ink might show a gold or green sheen, for example. It's most visible on smooth, slow-absorbing paper, and it's purely aesthetic, with no effect on performance.

Shimmer

Shimmer inks contain fine metallic particles that catch the light. They're visually striking but need more maintenance — the particles can settle and clog feeds. Shake the bottle before filling, and clean your pen more frequently when using them.

Flow (Wet vs. Dry)

Ink flow describes how freely ink moves through the pen. Wet inks flow generously — smooth to write with, but more prone to bleed-through on absorbent paper. Dry inks flow more conservatively — better for fine nibs and thinner paper, but they can feel scratchy in pens tuned for wetter flow. Most inks fall somewhere in the middle.

Drying Time

Drying time matters most for left-handed writers and anyone using broad nibs or wet inks. Faster-drying inks reduce smearing. Non-absorbent papers slow drying considerably — factor this in when pairing ink with paper.

How to Choose: A Simple Framework

Start with these questions:

• Does permanence matter? If yes, choose iron gall or pigment. If no, dye-based gives you the most options.
• What paper are you using? Smooth, well-sized paper rewards shading and sheen inks. Absorbent or lower-quality paper calls for drier, faster-absorbing inks.
• What nib size? Fine nibs work well with most inks. Broad nibs amplify every property — shading, sheen, and bleed-through alike.
• How often will you clean your pen? If infrequently, stick to well-behaved dye-based inks. Iron gall and pigment inks reward regular maintenance.

Paper Makes the Difference

The same ink can look completely different on different papers. A shading ink on cheap copy paper looks flat and feathered; on smooth, well-sized paper — Tomoe River is the classic example — it shows full depth and character. If you're investing in quality ink, pair it with quality paper.  Our notebooks collection is curated for exactly this kind of pairing — and our paper performance guide breaks down how different papers handle different inks.

Browse our ink range to get started — including our own house inks, made in collaboration with Anderillium.