Options of Fountain Pen Ink

The Evolution of Fountain Pen Ink 

The landscape of fountain pen ink has transformed from a limited selection of blue or black ink colours to an extensive, almost exhausting, array of colours. This vast choice of ink is considered one of the primary advantages of using a fountain pen. Over the decades, the composition of these inks has shifted significantly. During the "gold-age" of the 1920s and 30s, inks were primarily iron-gall-based, containing iron salts and tannic acid. While this made the writing permanent, the high acidity could eventually corrode the metal components of the pen.

Modern inks are typically dye-based or pigment-based. While older inks utilized natural stabilizers like plant resin or egg albumin, today’s formulas use synthetic stabilizers—such as polyvinyl chloride and polyvinyl acetate—to improve shelf life and flow.

Mechanics and Compatibility 

A fountain pen functions through capillary action, making ink flow a critical factor. The pen's feed contains narrow channels that allow ink to reach the nib while simultaneously letting air into the reservoir to prevent a vacuum being formed. When selecting an ink, consider the following compatibility guidelines: 

Brand Matching: You are not required to use the same brand of ink as your pen. 

Manufacturer Specifications: Some manufacturers say their inks are specifically balanced for their own feed mechanisms. 

Ink and Pen "Wetness": A "dry" ink (one with higher viscosity) paired with a "dry" pen feed can result in an inferior writing experience. Exclusions: Only use ink explicitly labeled for fountain pens. Avoid "India" or art inks, as these are designed for dip pens and can cause permanent damage if drawn into a fountain pen. 

Maintenance and Safety 

While vintage inks can offer beautiful shading, they must be used with caution. 

Mold: If a bottle of ink shows any sign of mold, it should be discarded immediately and never used in a pen. 

Evaporation: Old ink may become thick due to evaporation, which can clog the feed.

Scent: Unlike vintage Waterman inks, which were known for a specific "famous smell," modern inks generally lack that classic odor.

Pigment Inks: Because pigment-based inks contain tiny solid particles, they carry a higher risk of clogging the feed's narrow channels. Modern fountain pen pigments are made from microscopic solid particles that are naturally insoluble in water. Black Pigments: Most commonly made from Carbon Black (soot or lampblack). These are extremely stable and will not fade even after centuries of light exposure. Colored Pigments: Derived from minerals (like iron oxides), metals, or synthetic organic solids (like Phthalocyanines for blues and greens or Azo compounds for reds and yellows). Unlike dyes, which bond chemically with the paper, pigments are physical colorants. 

Pigments don't "soak" into paper fibers as deeply as dyes; they sit on the surface and become trapped in the paper's texture. They require binders (often synthetic resins or acrylic polymers in modern inks) to help them "glue" to the paper once the water evaporates. 

Because the pigment is a solid particle, it is unaffected by water or UV light. If you were to remove the pigment from the composition, you would lose the very properties (waterproofness and lightfastness) that make these inks desirable. 

But after all that, there are pigments and there are pigments.  Traditional pigments (like those in India Ink) have large particles that will immediately clog the narrow channels (capillaries) of a fountain pen feed. Modern "fountain pen safe" pigmented inks use nano-pigments, where the particles are milled down to less than 100 nanometers. These are small enough to flow through the pen without getting stuck, provided the ink doesn't dry out. Those last five words.  Enjoy your pigmented ink, but make sure you flush out your when when no in use.  If you can't follow that discipline, then pigmented inks may not be the best decision for you.   

There is a lot more to ink with pigments than just the pigments. If you use these for their superior fade resistance, establish a regular schedule to wash out your pen.

Defining Ink Characteristics

Choosing the "best" ink is a matter of personal preference, ranging from deep, dark tones to lighter colors with shimmer. To find your preference, it helps to understand the core characteristics of ink:

Saturation
The density of the dye or pigment; higher saturation results in darker, more vibrant colors but may increase dry time.

Viscosity
The fluid's resistance to flow. Higher viscosity means the ink flows more slowly, which can be beneficial for small, detailed writing.

Shading
The variation of color density within a single stroke. While some enjoy this aesthetic, others find it difficult to read on a full page.

Sheen
A secondary color that appears on the surface of the paper as the ink dries, caused by ink compounds that are not fully absorbed.

Dry Time
How long the ink takes to set, which is influenced by the ink formula, paper type, and local humidity.

Permanence
This includes Water-proofness (resistance to water once dry) and Light Resistance (the degree to which the ink resists fading over time).