What Is Fountain Pen Ink?

John BosleyFountain Pen EducationLeave a Comment

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What makes fountain pen ink so special? How is it different from other types of ink? Why can you only use certain types of ink in a fountain pen? These are all great questions. In this article, I want to discuss fountain pen ink and some of the different features you might find in different inks.

Fountain Pen Ink Basics

Before we talk about fountain pen ink in detail, let’s cover the basics first. Fountain pen ink is a liquid that is made up of dyes, water and other additives. These other additives can include surfactants (used to change the surface tension of the ink), pH modifiers and biocides (to prevent mold growth). Some newer inks use pigments in place of dyes, but these are relatively uncommon.

A good fountain pen ink has to satisfy a few different requirements. First, it has to flow out of the pen, which is why having the correct surface tension is important. If the ink flows too easily, it will run out of the pen and make a mess. If the ink doesn’t flow easily enough, it will not come out of the pen when you write. Another requirement is that it not clog or damage the pen. Inks with pigments or other solids that are suspended in the ink can potentially clog a fountain pen. Also, inks that are not made for fountain pens (discussed below) can have additives that may solidify inside of a fountain pen and clog it. Finally, inks with too high or low of a pH can actually eat away at some of the delicate parts of a fountain pen.

Now you should have an idea of why it is important to use an ink that is made specifically for fountain pens. Using anything else can have repercussions ranging from making a mess to destroying a pen. Next, let’s talk about the different types of fountain pen ink.

Types Of Fountain Pen Ink

The majority of fountain pen ink is made for writing. Available colors encompass the entire spectrum, ranging from simple blacks and blues, to bright greens and reds, to moody browns and grays. Chances are, if you have a favorite color, there is an ink to match.
Fountain Pen Ink Colorful Scribbles

Some inks are specifically made to be archival. This can mean a few different things, but for ink it typically refers to the permanence of the ink. Many inks will fade over time, especially if they are exposed to the sun, while archival inks are made to not fade. Some archival inks can also be waterproof, so if a document gets wet, you can be sure that the ink will not wash away. For many people, having an archival ink is not an important consideration, but you should know that such a thing exists in case the need ever arises.

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There are also some specialty inks that are not necessarily made for everyday writing. These might include highlighter and UV reactive/invisible inks. Highlighter inks are actually made so that they do not cover up text when you write over it, turning your fountain pen into a highlighter. UV reactive inks are basically invisible inks that are only visible with a UV light (such as a blacklight). While these might not be used on a regular basis, they are still fun inks to have around.

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Fountain Pen Ink – this ink is highlighter ink

Fountain Pen Ink Qualities

Fountain pen ink may have various qualities that can make your handwriting more dramatic and interesting. There are also qualities that can make some inks more or less suitable for particular pens. Let’s look at each quality in a bit more detail.


Shading is a quality that can be found in many fountain pen inks. Shading occurs when a written line of ink changes intensity, usually from lighter in the center to darker at the edges. You’ll typically encounter shading when you use flexible nibs, but it can also happen with non-flexible nibs. Similarly, an ink might shade when used in one pen but not in another, or on one type of paper but not another. It is not a fixed quality of the ink. It is something that can occur with the correct combination of ink, pen and paper.

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Fountain pen ink shading – notice how the edges of the letters are darker than the middles


Sheen is a quality that is mainly found in newer fountain pen inks. Inks with sheen can have a slightly metallic appearance in areas where the ink flow was heavier. This metallic appearance might be a completely different color than the ink itself. For example, Pilot Iroshizuku Yama-Budo is a rich purple color, yet the sheen is golden. Getting ink to sheen can be somewhat challenging, usually requiring heavy ink flow and slow-absorbing paper, but with the right combination of ink/pen/paper it’s possible to get some sheen out of particular inks.

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Fountain Pen Ink Sheen – notice the different colors in the ink

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Fountain Pen Ink Sheen Detail


Some newer fountain pen inks have metallic particles added to them that create a shimmer effect. Imagine glitter in your ink. Of course, these inks are made for fountain pens so they should be safe to use (unlike if you were to actually add glitter to ink). Still, you might want to use caution if you decide to use one of these inks in your pens, as there is always a possibility of clogging.

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Fountain Pen Ink With Shimmer – notice how it seems to sparkle


Wetness is a quality of fountain pen inks that can drastically affect your writing experience. A wetter ink feels like it flows out of a pen more easily and might work better with a flexible nib or a “dry” nib. A drier ink might feel like it doesn’t flow out of a pen as easily and might work better with a fine nib where you don’t want a heavy ink flow. While this isn’t a quality that you’ll find advertised, with a little online research you should be able to figure out if an ink tends to be more wet or dry.

Drying Time

Depending on your writing habits, the drying time of an ink can be a big deal. Some inks tend to dry very quickly, which means they won’t smear as easily if you happen to touch your paper shortly after writing on it. Faster drying time might also be a big deal if you are left-handed and run into issues with running your hand over wet ink. Other inks tend to take longer to dry. There is no real benefit to a longer drying time as far as writing is concerned.

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Wet vs Dry Fountain Pen Ink

Other Qualities

As I mentioned above, there are other qualities that inks might have as well. These might include whether they are archival or specialty inks. Some inks are scented, which is nice if you want your letters or notes to have a pleasant smell. Some inks have pigments instead of dyes in them, which can result in brighter, bolder colors. Finally, the ink bottle is not to be discounted when shopping for ink. Some bottles are designed with ease of filling in mind, while others are designed to be visually pleasing.

Vintage Ink

Many people (including myself) enjoy using older inks as well as new ink. You might wonder if they are safe to use. The short answer is typically yes, but you will have to exercise some caution. To learn more about what you need to know before using vintage inks, read my article on what kind of ink to use in a fountain pen.
Vintage Fountain Pen Ink Bottles

Other Types Of Ink

You’ll also find many different inks that are not made for fountain pens. These include India ink, calligraphy ink, Sumi ink, dip pen ink, acrylic-based ink and more. These inks are intended to be used with pens such as dip pens, illustration pens, brushes and other non-fountain pens. Using any of these inks in a fountain pen can damage or destroy it.

There are many reasons that these inks are so dangerous for use in fountain pens. Some have more pigment in them, which means that they can clog the delicate feed system of a fountain pen. Others have additional compounds in the ink such as shellac, which can solidify inside of a fountain pen. Regardless of which type of ink you’re looking at, if it is not made specifically for fountain pens, it does not belong in a fountain pen.


To wrap up this discussion of fountain pen ink, there are a few different things that you need to remember. The most important is that not all ink is fountain pen ink! You should only use inks that are made specifically for fountain pens. Fountain pen inks have many different qualities and not all of them will perform the same. Additionally, an ink might look and feel different depending on which pen and paper you use with it. Whether you decide to use modern or vintage inks, a little caution can go a long way.

Having so many different inks available is one of the most enjoyable aspects of writing with a fountain pen. Not only can you choose an ink to fit your mood, but you can also choose an ink to fit your particular pen, paper and writing style. The possibilities are limitless, so be sure to try out different combinations until you find one (or many) that’s perfect for you.

Hi, my name is John. I’m a Colorado-born professional photographer who currently lives in San Francisco. I’ve been using and collecting fountain pens for over 20 years. I got my first one in college when I got bored taking notes with ballpoints and pencils. Since then I’ve bought and sold hundreds of pens, but have consistency in my love of Esterbrooks.

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