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Inks: The Good, the Bad, and the Ugly

(This page revised June 23, 2021)

Reference Info Index | Glossopedia  ]

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 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.

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 gelatine or shellac, or both, 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:

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. Diamine, which has been making inks since 1864, offers a much more exciting range of colors and with characteristics very similar to those of Waterman, so that now I recommend these two brands, the majority of whose colors sport very high scores. Waterman’s Audacious Red and Absolute Brown and 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.

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 some properly adjusted 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 to the right.

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’m leery of giving it medium or high score because one bottle I had some years ago never dried. At one point, a document I had written six months earlier with Sherwood Green smeared while being handled. On the other hand, Private Reserve Tanzanite, sometimes called “the Ex-Lax of inks,” stains badly and flows far too readily. It scores a 2 or a 3. If you like the color of Tanzanite, dedicate a specific pen for that ink; or try mixing Waterman Serenity Blue and Waterman Tender Purple in equal parts. The resulting color, which I have dubbed “Blurple,” is very similar to that of 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.

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 Noodler’s and Private Reserve 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 seem to be 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 likely to be more prone 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 Noodler’s inks, including 54th Massachusetts and others whose identities I have not yet pinned down, will reduce latex sacs to goo. This is not the “gummy sac” problem that is caused by improperly formulated latex. Although I cannot state the cause with certainty, I believe it probable that these inks contain copper-based dyes, which tend to produce brilliant colors — but copper is a powerful catalyzing agent that acts on rubber. This problem was recognized historically: Parker SuperChrome inks (sold from 1948 to 1956) used copper-based dyes and contained a chemical called a “copper inhibitor” to prevent the copper in the dyes from destroying rubber sacs and seals.

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.)

Inks with a Non-Neutral pH: Your Pen Could Be on the Menu

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 tended to be highly acidic.) Parker made the “51” fountain pen of acrylic because the company’sd 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 nitrated cellulose into celluloid, the ink breaks down the celluloid and could conceivably convert it into something much more flammable if not actually explosive.

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 ink bottles labeled Parker 51 or Parker SuperChrome. These are vintage inks, but there are still some bottles floating around. 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. It wasn’t good for pens, not even the “51”, and Parker withdrew it in 1956. The photo below shows what happened to the sterling silver breather tube from an Aero-metric “51” that had been used with SuperChrome.

Swiss cheesed breather tube

Among modern inks, Noodler’s Baystate colors stain terribly and are are also corrosive enough to destroy some plastics. Known to be susceptible are the materials from which modern Pelikan nib units and the feeds in Pilot and Lamy pens are made, as well as the body materials of Wality piston-fillers and Waterman Philéas and Kultur pens. There are doubtless others not yet known. 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. Clearly, the pH of an ink is not the only factor that can render that ink dangerous to pens.


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 Mike Kennedy at Indy-Pen-Dance 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.

Pen body
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?

More Crud: Mold

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. Private Reserve, for example, is infamous for recurring mold issues.

Your Grandfather’s Ink: Permanent, Waterproof, and a Little Quirky

Iron gall ink for fountain pensI’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. 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.

Nanoparticle ink for fountain pensNote, however, that a new type of “permanent” 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. While nanoparticle inks are not absolutely permanent because they do not react chemically with the paper, they are indeed waterproof once dry, and they are used by many artists to do ink-line work over which a watercolor wash will be used. Among these inks, I have more than a little experience with Platinum Carbon Black. So long as the pen is flushed clear and re-inked more often than would be required for an ordinary ink, I consider this ink to be safe and eminently usable if its being waterproof is sufficient for the user’s needs. In general, any of the nanoparticle inks can be considered safe for fountain pens, but I rate them as medium-to-high-maintenance inks because of the need for more frequent flushing; the very existence of particulate matter brings with it more risk of clogging than is present with inks that are true solutions.

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. Fish breathe by extracting dissolved oxygen gas from the liquid water in which they live. Some precious stones are solutions of various metals in corundum (aluminum oxide, Al2O3); rubies are red due to the presence of chromium.  Return

  2. 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.  Return

The information in this article is as accurate as possible, but you should not take it as absolutely authoritative or complete. If you have additions or corrections to this page, please consider sharing them with us to improve the accuracy of our information.

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