Inks: The Good, the Bad, and the Ugly

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(This page revised November 5, 2019)

Fountain pens require ink. But what kind of ink? And why? And how?

First Principles

Fountain pen ink bottleGOOD: Feed your fountain pen a steady diet of fountain pen ink. Period. This injunction may seem obvious, but it is not quite so obvious as it appears. Fountain pen ink is a solution. To the chemist, a solution consists of a fluid in which other substances are dissolved (the solvent), and the dissolved substances (the solutes). The solutes are actually reduced to the molecular level, the same as the solvent, and all the different molecules are mixed up evenly to create a uniform fluid, a pure liquid[1] that contains no microscopic particles of solid material. The solvent in fountain pen ink is distilled water, and the solutes are dyes, wetting agents, and mold inhibitors. Because it’s a solution, fountain pen ink contains no solid matter at all. This is an important point to remember.

BAD: Certain manufacturers of artists’ inks and paints, such as Winsor & Newton, market some of their calligraphy inks as being suitable for fountain pens. Don’t believe it. Calligraphy inks are pigmented; that is, they derive their color not from dissolved dyes but instead from finely ground solid matter — like paint. In theory, the pigment in these inks is so fine that it will remain in suspension under the impetus of Brownian motion in the liquid component of the ink. Unfortunately, this does not always happen. In a calligrapher’s dip pen any separation of solid components is not a problem because the nib is easy to remove and clean and because there is no feed with hidden passages to clog. But as the ink passes through the very fine fissures of a fountain pen’s feed and the slit of the nib, pigment particles come in contact with the walls of these passages and are attracted to the surfaces. A layer of pigment builds up and will inevitably clog the feed, the nib, or both. The modern plastic feed shown here illustrates the myriad nooks and crannies into which ink can find its way before drying out to clog the works.

Note, however, that a new type of ink has appeared in the past few years. Called nanoparticle ink, it contains pigment — but the pigment is much more finely ground than in traditional calligraphy inks; so finely ground, in fact, that Brownian motion can easily keep it suspended. In general, nanoparticle inks can be considered safe for fountain pens, but I rate them as high-maintenance inks (see below) because the very existence of particulate matter brings with it more risk of clogging than is present with inks that are true solutions.

Fountain pen ink bottleThere are other inks, less obviously troublesome, that you should avoid. Right at the top of this list is inkjet-printer ink. This stuff might seem appealing; refills are inexpensive, and the colors — especially the ones rated for 70 years or longer — are remarkably permanent. But there are some very bad things in inkjet ink. It frequently uses pigment, not dye, for color, and there are also particulate resins for better adhesion. Various glycols (diethylene, alkylene, etc.) enhance penetration; these substances can exacerbate bleeding and feathering in a fountain pen. They also retard evaporation, making the ink take longer to dry on the paper.

Another kind of ink whose potential for disaster is not immediately obvious is whiteboard marker ink. Like inkjet ink, this stuff is based on pigment, not dye, and that means it can and will clog feeds. It also contains particulate resins for adhesion as well as various alcohols (such as ethanol and 2-propanol) that can damage the feed and barrel in some types of fountain pens.

Nib and feed with white-outUGLY: India ink, white-out, and other similar fluids are certain death to fountain pens. These fluids are pigmented, and they are frequently not water based. (India ink is water based; but it also contains gum arabic for permanence, and it takes great pleasure in gumming up fountain pens.)

From an email I received from Mike and Linda Kennedy at Indy-Pen-Dance: “The nib and feed in this image came out of a pen in which white-out was used. Just separating these parts required several rounds in an ultrasonic cleaner with Rapido-eze, and that’s when we took this picture. We were able to get the mess cleaned up, but it was an expensive learning experience for the owner of the pen. Believe it or not, we have received (and repaired) fountain pens that had been filled with latex paint and model paint!”

Maintenance: Low, Medium, or High

Even when you’re scrupulous about using fountain pen ink only, your pen can experience ink-related problems. These difficulties happen because even the best inks are not perfect; and when pen maintenance is also imperfect, writing performance can suffer.

Using fountain pens, like shaving with a cut-throat razor, is partly a sensual experience, and it involves ritual. Maintaining your pens is part of the ritual. Every ink requires you to commit a certain amount of time and effort to using your pens. Your choice of inks will depend on how much fiddling you enjoy balanced against how much you are willing to tolerate. But not all inks require the same amount of involvement; the less trouble a given ink requires, the higher its usability score. An ink’s usability score is a composite rating, so to speak, that reflects the amount of time and effort you have to put into using that ink. The composite is built on factors such as these:

Flow. Inks that flow well — but not too well — score high because they don’t make the pen fight back when you’re trying to write with it. Inks with good flow will start readily and will flow evenly, without exhibiting a tendency to skip or to produce dry patches. Inks that flow too well often tend to feather or bleed, especially on cheap papers, and this sort of excessive flow lowers an ink’s score.

Staining. Inks that stain little or not at all score high because they don’t make you disassemble and scrub out your transparent or partially transparent pens so you can see through them or polish the plating off your two-tone nibs trying to keep them bright. The color of a given ink affects its staining tendency; reds and other colors containing red dyes have a high tendency to stain (and therefore somewhat lower scores), while pure blues — especially washable ones — stain little or not at all.

Lubrication. Inks that lubricate well score high because they give you a smooth glide instead of making your nib feel dry and gritty so that you have to push harder. Some users refer to inks that lubricate well as being “greasy,” but there is no actual grease in fountain pen ink


Lubrication, as used here, does not refer to the addition of special substances for the ostensible purpose of lubricating the pen’s piston or other filler parts. It refers to an inherent quality of all fountain pen inks, a quality that depends upon the choices made with regard to the ink’s basic components.

Clogging. Inks that don’t clog score high because they don’t make you disassemble your pen to floss the nib and feed. Typically, the more intensely saturated the color is, the greater are the dye load and the concomitant risk of clogging.

“Creepability.” This is a handy made-up word that refers to an ink’s tendency to display nib creep. Inks that tend not to creep score higher because they don’t make you take out a tissue and wipe the nib to no avail every few minutes. This also raises your spirits by reducing your stress level.

Waterman inks were the first high-scoring (low-maintenance) inks I discovered. On a scale of 1 to 10, I rate Waterman inks a solid 10. They flow remarkably well under a broad variety of conditions in almost any pen. They lubricate exceptionally well, imparting a glassy-smooth ride. They are not heavily saturated, and the dyes in them tend to be relatively nonstaining. Waterman Mysterious Blue is almost stain free. But Waterman’s palette is not the most inspiring in the world. Recently Diamine, which has been making inks since 1864, appeared in the marketplace with a much more exciting range of colors and with characteristics very similar to those of Waterman, so that now I rely almost entirely on these two brands, the majority of whose colors sport very high scores. Some Diamine colors, however, especially their reds and colors containing red dyes, such as pinks, violets, oranges, and browns, appear more prone to clogging issue, and these inks have much lower scores. As it happens, I use Skrip Red (made in Slovenia) in one pen at my workbench, and it’s remarkably good. Its being red reduces its score slightly, but not enough to be a major consideration for me.

Toward the middle of the scale fall the vast majority of inks, including Aurora, Pelikan, Parker Quink (except the black, which scores surprisingly low because it exhibits serious flow issues in Parker pens), J. Herbin, Lamy, Omas, Namiki, and many more.

On the high-maintenance (low scoring) end of the scale we find several brands of very heavily saturated “boutique” brands, most of which score in the range from 3 to 5. As described earlier, fountain pen ink is a solution; the solvent is water, and the solutes are the dyes, the surfactant, and the fungicide. The nature of chemical solutions is that as the temperature declines, the solvent can keep less of the solutes in solution. The more solute you start with, the more likely it is that some of it will precipitate out (come out of solution) as time passes and conditions such as humidity and temperature vary. As the dye comes out of solution it precipitates onto the interior surfaces of the pen — particularly the fissures in the feed. This leads eventually to a clog. See the Science Experiment below.

Some boutique inks also score lower because of differences in flow and drying rate among their various colors. Private Reserve Sherwood Green is a lovely color, but I give it a score of 2 because it sometimes never dries. (I've come back six months after writing something with it and smeared it while handling the paper.)[2] On the other hand, Private Reserve Tanzanite, sometimes called “the Ex-Lax of inks,” stains badly and flows far too readily. It also scores a 2 or a 3. If you like the color of Tanzanite, try mixing Waterman Serenity Blue and Waterman Tender Purple in equal parts. The resulting color, which I have dubbed “Blurple,” is virtually indistinguishable from Tanzanite.

In the same way that a heavily saturated ink can precipitate in your pens, it can also do so in the bottle. In fact, if you habitually leave ink bottles open for extended periods, the water gradually evaporates, rendering the solution more saturated than the manufacturer intended. Even otherwise “safe” inks can do this. Do not shake an ink bottle before filling your pens from it — and if you ever see a sludge in the bottom of an ink bottle, the wisest course if you want to avoid clogging is to discard the contents.

Science Experiment

To make rock candy:

  1. Find a glass jar with a capacity of about 1 quart (about 1 L). Tie one end of a piece of rough string (wool, cotton, or sisal) to a pencil that is long enough to bridge the opening of the jar. Adjust the length of the string so that the loose end does not quite touch the bottom of the jar inside. Tie the loose end to a small metal ob­ject, and check to make sure that the weight does not touch the bottom of the jar.

  2. In a large saucepan, bring 1 U.S. pint (473 ml) of water to a boil. Add 1 U.S. quart (946 ml) of ordinary sugar. Stir until completely dissolved. Now begin adding sugar a tablespoon at a time, stirring to dissolve the sugar. When you have added enough sugar, the next spponful you add will not dissolve. Stop adding sugar; you have created a saturated solution.

  3. Pour the sugar syrup into the jar, but do not allow any un­dis­solved sugar to get into the jar. Suspend the string in the syrup. Lay the pencil across the top of the jar, cover the open­ing with a few sheets of newspaper, and go away. As the syrup cools, the sugar begins to come out of solution and stick to the string, even­tu­ally growing into very large crystals.

  4. After a few days, you can pour out the remain­ing water. Hang the sugar crystals up to dry for a day or so, then break them apart by hitting then with a meat tenderizer.

Now imagine that the string is your pen‘s feed and the sugar is the dye in your ink. There is always some evaporation of the water in the ink, and this is why feeds become clogged if not kept clean.

Let it be clearly understood that the designation of a given ink as high maintenance (by me or by anyone else) should not be construed as a warning to avoid said ink. With proper care, including more frequent flushing, use in opaque pens only, adjustment of nibs for richer flow, etc., these inks are eminently usable, so long as you use them in pens that like them and give them the attention to maintenance that they need. Please note also that I do not have a documented scale of maintenance levels. This is all a gut-feel sort of thing, based on experience and anecdotal information.


For many years, I’ve tried not to say anything negative about particular inks, but I am now convinced that there are several problems that can be traced to the use of Private Reserve or Noodler’s inks. Among these problems are flow issues and clogging, mold, staining, and actual destruction of pens.

Along with certain other “boutique” inks, these two brands are more prone to clog than more conventional inks because of the heavy dye load they use to produce their deeply saturated colors. Also, some Private Reserve inks behave just like phthalocyanine- and quinacridone-based watercolor paints, which use pigments for their color and are more likely to produce clogs than saturated dye-based inks.

Noodler’s “bulletproof” inks contain a component that causes the dye in the ink to bond chemically with the paper. Unfortunately, this bonding agent is particulate, not in solution. It settles, and you have to shake the bottle to disperse it when filling a pen. It also settles in the pen, and it can cause clogs. To combat (but not cure) this tendency, Noodler’s adds extra surfactant (wetting agent), which can cause bleeding and feathering.

Some other Noodler’s inks, whose identities I have not yet pinned down, will reduce latex sacs to goo. This destruction occurs without the presence of metal; it is not the “gummy sac” problem that is caused by improperly formulated latex.

Private Reserve inks are known to have had mold issues in the past, but with a changer of ownership after the death of founder Terry Johnson, the problem appears to have been solved.

Various Private Reserve and Noodler’s inks are known for staining pens, and at least some Noodler’s inks are known to destroy pens.

Experience has shown that Noodler’s Eel inks often do not flow properly in pens that work with virtually any other kind of ink. I see no need for an ink with the “lubricating” properties of Eel, and I do not recommend its use. (If pen makers thought this sort of ink was a good idea, they would be selling it and taking the profits to the bank.)

Some ink manufacturers state that the pH (degree of acidity or alkalinity) of an ink is not a factor in whether that ink can damage pens. This assertion appears to be untrue.

Strongly alkaline inks can eat some organic resins, especially celluloid and Omas’ vegetal resin — which is very much like celluloid. (Omas’ own inks tend to be highly acidic.) Parker made the “51” of acrylic because its super-quick drying “51” ink turned out to like noshing on celluloid pens. (The problem was largely due to the ink’s alkalinity that contributed to quick drying by eating into the paper’s cellulose fibers.) Noodler’s Polar inks seem to be similarly harmful, at least to celluloid; it appears that these inks leach the camphor out of the celluloid. Because camphor is the plasticizing and stabilizing agent that turns guncotton into celluloid, the ink breaks down the celluloid and could conceivably return it to its original explosive state.

Most Japanese inks are alkaline. Alkaline inks are hostile to latex. I have experimental evidence that at least some of the Pilot Iroshizuku colors will destroy latex sacs. For this reason, I recommend that you avoid using Japanese inks in sac-filling pens as well as in pens that are made of organic resins and use the barrel for the ink reservoir (as described in the preceding paragraph).

More ugliness is contained in bottles labeled Parker “51” or Parker SuperChrome. These are vintage inks, but there are still some bottles in existence. Don’t be tempted to use them! Parker introduced the super fast-drying “51” ink in 1941 for use with the “51” pen — and no others. The problem was that “51” ink ate pens. It didn’t eat the “51”, but it did cause the diaphragm in the pen’s Vacumatic filling system to ossify very rapidly. With the 1948 introduction of the Aero-metric “51”, Parker withdrew ”51” ink, replacing it with SuperChrome. The newer ink wasn’t as hostile to pens as the old, but it still had a pH of about 12, and it wasn’t good for them, and Parker withdrew it in 1956. The photo below shows what happened to the sterling silver breather tube from a “51” that had been used with SuperChrome.

Among modern inks, Noodler’s Baystate colors stain terribly and are are also corrosive enough to destroy some plastics, including the materials from which Pilot and Lamy feeds are made and the resins used in the barrels of some makers’ piston-filling pens. (See the photos below, showing an undamaged Vanishing Point feed and one that has begun to die due to exposure to Baystate Blue, which has a measured pH of 4.53.)

Some Noodler’s inks do not play nicely together; this means that you cannot mix them. The Pelikan M1000 shown below was sent to Chartpak, Pelikan’s U.S. distributor, for repair. To remove the stuck-on cap, the Chartpak repairer had to disassemble it; then the pieces could be popped off the barrel. The section had come loose from the barrel, and the interior of the barrel was badly stained and seriously cracked. Because the pen was a gift to its owner from a now-deceased relative, the repair department manager at Chartpak sent it to us in the hope that it could be saved instead of simply being thrown in the trash. No such luck. It is not known what exact inks had been used in it beyond that they were all Noodler’s inks that the owner mixed to produce a custom color, but what they did to the pen is horrifying. The pen was not reparable.


For specific information on the pH of various inks, read Inks: Report on the pH of More than 60 Inks.


Creeping Crud: the Dreaded SITB, or Slime in the Bottle

Sometimes an ink can undergo an adverse chemical reaction among its various components: the fungicide might react slowly with the dye and — over time — produce a slimy film or threadlike bits of slime. This is bad news. I’ve seen suggestions that filtering the slime out will leave the remaining ink usable, but it’s not really a good idea. There is no way to tell what the chemistry of the ink is anymore; if the reaction involved the fungicide, for example, the ink no longer contains sufficient mold inhibitor, and it can develop mold very suddenly — in the bottle or in your pen! One visit to a pen repairer to have the pen cleaned out will cost you at least the price of two bottles of ink. Is it worth the risk?

To a chemist, the aniline dyes used in fountain pen inks are organic in nature, and the very presence of these dyes in ink can give rise to mold because to mold they look like food. Mold spores are everywhere around us; every time a bottle of ink is opened, some spores find their way from the atmosphere into the ink. Inks contain chemicals to inhibit mold growth, but not all inks contain enough mold inhibitor.

Your Grandfather’s Ink

I’ve left one particular type of ink until the end. Iron gall ink was invented more than 1500 years ago. It was used by innumerable nameless scribes to copy sacred manuscripts; by great secular writers and thinkers such as Voltaire, Shakespeare, and Leibniz; and by ordinary people. When fountain pens came into existence, iron gall ink made the leap to the new technology, and it is still in use today because it is a very permanent ink. But it has a couple of drawbacks. First, but of less serious consequence for most of us, is its reputation for destroying, over the course of centuries, the paper on which it is used.[3] Of more concern to you, as a fountain pen user, is that it is rather acidic: it can corrode metal pen parts such as steel nibs and cartridge nipples, and plated trim rings — every part that comes in contact with it. Only gold alloys are safe from its ravages; if your pen features a gold nib and has no other metal parts that are continually exposed to the ink (such as a metal cartridge nipple), you can use iron gall inks such as Montblanc Blue-Black and Diamine Registrar’s ink with impunity.

You should note that iron gall ink is not the only acidic ink that is currently available. Your best course, if you’re concerned about the pH of your inks, is to look for inks that advertise neutral-pH formulas.

The Bottom Line

Be sensible. Know what inks you are using and how to handle them; and take good care of your pens to ensure that they’ll deliver the writing performance that was designed into them. If you’re like most collector/users, you have more pens than you want to use at one time — when you take a pen out of your rotation, flush it thoroughly (see Care and Feeding: How to Pamper Your Pens), and let it dry uncapped overnight before putting it into your pen chest for a bit of well-earned relaxation.

  1. The discussion of solutions in this article is necessarily simplified. For example, it speaks of liquids, but gases and solids can also form solutions. For example, fish breathe by extracting dissolved oxygen gas from the liquid water in which they live.

  2. As of this update, in November 2019, this behavior is under investigation by the owner of Private Reserve.

  3. For those of a curious disposition, the destruction of paper by iron gall ink is simply a greatly accelerated form of natural decomposition, catalyzed by active soluble salts remaining in the ink (frequently due to a lack of understanding as to the correct form of iron sulfate to be used in preparing the ink). Properly balanced ink does not contain excess soluble salts and is, for all practical purposes, not harmful. For more information, see the Glossopedia entry on iron gall ink.


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