Can You Dilute Fountain Pen Ink? What You Must Know

Fountain pens are making an impressive resurgence, and more and more people are finding themselves drawn to using these fine writing implements. With the growing popularity of fountain pens comes a growing fascination with fountain pen inks. This often leads to some ink-related questions, such as, can you dilute fountain pen ink?

Fountain pen ink can be diluted. These inks are optimized for fountain pens, but if the ink has become dry, it can be diluted to revive it. Diluted ink dries faster and flows more easily, and is less likely to clog. Only use distilled water, and do not dilute too much, or the ink will be ruined.

Fountain pen ink often works well right out of the bottle, but there are some circumstances when the pure ink is not quite right. Certain applications may require weaker ink, or ink may be clogging a pen. These are some of the situations that may lead a writer to ask, “can you dilute fountain pen ink?” let’s have a closer look at fountain pen inks and what happens if they are diluted.

Can You Dilute Fountain Pen Ink?

Fountain pen ink is a special type of ink. It is not oil-based as many other writing inks are, and it is not as thick as other inks either. This ink is water-based and specifically designed for use in fountain pens.

However, there are occasions when fountain pen ink is a little too viscous, or the ink has dried out, or if the ink is causing a pen to become clogged. This can be a serious problem for many fountain pen users, and ink frustrations have caused many to abandon fountain pens altogether.

The truth is, fountain pen ink can be diluted, and it is often the solution to the problems that many encounters with this type of ink.

The fact that fountain pen ink is water-based means that more water can be added to it without causing the ink to separate, as long as the right water is used to dilute it.

Fountain pen ink can be diluted, and many fountain pen users exclusively use ink that has been diluted with water either to solve a specific problem that they struggle with or simply because they prefer the ink that.

This type of ink is designed for use in fountain pens, and there are many who swear against diluting fountain pen ink, but occasionally there is no other option, and adding pure distilled water to the ink will not do any harm to the ink nor to the pen that writes with it.

There are many recipes for diluting fountain pen ink, and some inks must be diluted more or less than others for best results. Everyone prefers their own ink their own way, and diluted ink is no exception.

There are many fountain pen users who dilute their ink for various reasons, and all those who do agree that it has improved their fountain pen experience.

Let’s go a little deeper into diluting fountain pen ink, why it is done when it is necessary, and how to do it.

Why Dilute Fountain Pen Ink?

There are so many different variations of fountain pen inks out there. There are inks of all different colors, viscosities, compositions, pigments, and ages, and each one has its own properties when it comes to writing.

Along with the many hundreds of different inks come with many thousands of different types of fountain pens and nibs and many millions of fountain pen users.

This combination of variants means that plenty of reasons to dilute fountain pen inks have cropped up over the years.

The most commonly experienced reasons for diluting fountain pen ink are:

  • To decrease the drying time of the ink.
  • To improve the flow of the ink.
  • To prevent the ink from clogging the pen.
  • To lighten the color of the ink.
  • To revive ink that has dried or has thickened due to water evaporation.
  • To stretch a bottle of ink further and make it last for a longer time.
  • To decrease page see-through.

If fountain pen ink is a little too viscous, it often takes a very long time to dry. This is especially true for those who reside in places with high humidity. This can be an issue for anyone who uses a fountain pen as a daily pen, as smudging occurs very easily, rendering notes illegible and covering the hands in smudged ink.

Introducing a small amount of distilled water to the ink thins it out just enough that the ink dries in significantly less time, making the fountain itself far more useable.

Another issue with fountain pen ink being slightly too thick is the fact that it may not flow very well out of the fountain pen nib. This leads to inconsistent pens trokes and blotchy letting, which can be very frustrating. Water is a good way to improve the fluidity of the ink enough that this is no longer an issue.

Thick ink can not only prevent a pen from flowing well, but it can clog the feed of the fountain pen entirely, which renders the pen useless. The ink will remain clogged in the pen until it is cleaned out, which can be a time-consuming process.

A quick solution to this is to dilute the ink. This will loosen the ink enough that it will no longer cause any clogging issues within a fountain pen. This only requires a very small amount of water, just enough to prevent clogging.

A very common problem that is experienced by many who write with fountain pen ink is that the color of the ink is often too dark. This problem is especially prevalent with colored inks when the user would like the ink to be a lighter shade.

Diluting the ink with water will lighten the shade of the color, bringing the ink closer to the desired share very easily.

As fountain pen ink is water-based, when it is left unused for a long time, water evaporates from the ink. This causes the ink to seize and dry and makes the ink unusable for a fountain pen.

Adding a little water to replenish what has evaporated will revive the old fountain pen ink, making it perfectly safe for use in a fountain pen and saving the bottle of ink.

The special ink that is used for fountain pens can be expensive, especially so in certain parts of the world. Stretching a bottle of ink to last for as long as possible is a necessity for many writers, and adding water to a bottle of ink helps it go further.

Another issue that many encounter when using fountain pens, especially on less-expensive paper, is “ page see-through.” This occurs when ink shows through the back of a page, making it impossible to write on both sides of a page.

Diluting fountain pen ink is a good way to decrease the ink’s intensity, helping to decrease page see-through.

All of these problems are frequently encountered by fountain pen users, and slightly diluting the ink used in the pen is a simple solution to all of them. However, ink should always be diluted in small batches, and the process should be done very carefully to avoid ruining the ink.

How Does Diluting Affect Fountain Pen Ink?

There are many who stand firm on the premise that fountain pen ink should never be diluted. This is usually because fountain ink is purposefully designed and formulated for use in fountain pens, and many believe that diluting it will ruin the ink.

This is, however, untrue. Diluting fountain pen ink will not ruin or damage ink; it will not even degrade the ink, as long as the process is done correctly and if distilled water is used.

There have been some mishaps with diluting fountain pen ink in the past that have occurred due to factors such as using tap water for the dilution. Tap water is not pure and contains minerals and impurities.

These impurities negatively affect fountain pen ink and cause it to separate, making it unusable in a pen.

This is why it is crucial to use distilled water when diluting ink. It will not contaminate, degrade, or negatively affect the ink at all. The only result is thinner ink.

High-quality fountain pen ink will not be harmed by using pure water to dilute it, but there are some lower quality inks that may not fare as well, simply because they already have a higher water content, but these links do not generally need to be diluted, to begin with.

Even old sinks can be revived by adding a little water to them, and diluting these inks only improves them rather than degrading them.

This is because fountain pen inks are water-based. Other inks are ruined by adding water to them, especially those that are oil-based, as water separates the ink, but fountain pen ink is mostly water, to begin with.

Is Diluting Fountain Pen Ink Safe For Fountain Pens?

This is another question that is frequently asked on this topic. Many wonder whether or not using a diluted ink will somehow harm the fountain pen that writes with it.

Using diluted ink will not harm a fountain pen. Water is used to clean out fountain pens and therefore is safe for the pen to be in contact with.

If the link that is placed in the pen is too diluted, the ink will simply flow through the pen quickly, causing no harm whatsoever.

If the ink is not diluted enough, it will be no different to using regular fountain pen ink, which is not harmful to these pens at all.

Using diluted fountain pen ink is safe for all fountain pens!

How To Dilute Fountain Pen Ink

There are many recipes for diluting fountain pen ink, and each writer who dilutes their ink has their own recipe that works well for them.

It is important to experiment with how you dilute your inks based on the pens that you write with, the inks that you use, and the climate conditions where you live.

Very thick inks will require more water to dilute them sufficiently, and iron gall inks will need more water to be thinned out than any other fountain pen ink.

When diluting ink, never dilute an entire bottle of ink at once unless you are absolutely certain of the ink-water ratio that you like best for your ink.

The best method is to decant a small amount of ink from the bottle into another jar or other receptacle for mixing with water. Using a syringe or another implement with liquid measurements on it is a great help here as well.

Once the fountain pen ink has been removed from the bottle and placed in a separate container, ad in the desired amount of water and mix thoroughly. The water should not separate from the ink; if so, there are impurities in the water that you are using, and you should restart with purer water.

To check if the ink is at the consistency and opacity that you desire, try it out on paper. If you have access to a dip pen, now is the perfect opportunity to use it, otherwise dipping a thin object into the ink, such as a toothpick or a paper clip, and using it to draw a line will give you some idea of the condition of the ink.

If you want the ink to be thinner, add more water; if you would prefer the ink to be thicker, add more ink. Keep going until you nail down the perfect ink for your liking.

To be more precise, there are a few recipes that have been successfully used by fountain pen users. Some of the more popular combinations are:

When diluting thicker inks, 10ml of water for every 45ml of ink (especially for larger mixtures of ink, e.g., for an eyedropper pen)

Thin inks can be diluted in small amounts of 2.5ml of ink mixed with 0.5ml of water (especially for a fountain pen cartridge)

Many writers are satisfied with a simple 2:1 ratio of ink to water, finding it to be the best ratio for most fountain pen inks.

The ratio of water to ink should be determined by the ink that you are using and how thin you want to make the ink.

The pen that you are using also plays a role here, and writing pens that are drier should have less diluted inks, while wetter pens, such as those with flex nibs, should have a more diluted ink that flows better.

At the end of it, the ink dilution that you use should be determined by you. The only way to find which solution works best is to experiment a little and find the perfect ink for you and your pens!


Fountain pen ink is just as important as the fountain pen itself. Not all fountain pens write very well with pure inks, and this can lead to many problems that need urgent resolution.

Problems such as clogged feeds or nibs, long drying times, excessive page see-through, and old ink that has become evaporated can all be solved by mixing a small amount of water with the ink.

You can dilute fountain pen ink, and furthermore, it is perfectly safe for the ink and for the pen that writes with it, so long as the process is done correctly.

If your inks are too thick, or if you need to stretch that last bottle of ink a little further, try diluting your fountain pen ink. The process of diluting fountain pen ink is more simple than you may have thought, and you may actually prefer the diluted ink over the regular ink!

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