Permanent ink is built from three core ingredients: a colorant that provides the visible mark, a solvent that keeps everything liquid until applied, and a resin binder that locks the color onto a surface once the solvent evaporates. The binder is what separates permanent ink from washable ink. Without it, color sits on top of a surface and washes away. With it, color bonds to the material and resists water, handling, and fading.
You can make permanent ink at home using several approaches, from centuries-old iron gall recipes to simple carbon-based formulations. The method you choose depends on what you’re writing with, what you’re writing on, and how long you need it to last.
What Makes Ink Permanent
Permanence in ink comes down to two properties: water resistance and lightfastness. Water resistance means the ink won’t dissolve or run when wet. Lightfastness means it won’t fade under prolonged exposure to sunlight. Commercial permanent inks are tested against the Blue Wool Scale, which rates color durability from 0 (fades almost immediately) to 8 (no detectable change). A rating of 8 is considered fully lightfast and permanent.
The colorant you use matters enormously. Pigments are tiny insoluble particles suspended in liquid, while dyes are fully dissolved. Pigments generally offer superior lightfastness because their particles are physically trapped in the binder film rather than relying on chemical bonds that UV light can break. Carbon black, the pigment in soot and lampblack, is one of the most permanent colorants known. Manuscripts written with carbon ink over a thousand years ago remain legible today.
The binder creates permanence by forming a tough, water-resistant film as the solvent dries. In commercial permanent markers, this is typically a synthetic resin polymer dissolved in alcohol. For homemade inks, natural resins like shellac serve the same purpose. Shellac is water-insoluble once dry and creates a stable bond between carbon particles and the writing surface, remaining resistant to moisture over time.
Carbon Black Ink With Shellac Binder
This is the most straightforward method for making a genuinely permanent ink at home. You need three things: carbon black powder (or soot you collect yourself), shellac flakes, and a solvent like denatured alcohol or isopropanol.
To collect your own carbon black, hold a glass jar or ceramic plate over a candle flame, keeping it about an inch above the tip. Soot will deposit on the surface. Scrape it off with a razor blade or knife and collect it in a small container. This takes patience. You’ll need roughly a teaspoon of soot for a small batch of ink, which can take 30 minutes or more of collection.
Dissolve shellac flakes in denatured alcohol at a ratio of about 1 part shellac to 5 parts alcohol by volume. Let the flakes soak for several hours, stirring occasionally, until fully dissolved. The solution should be thin and slightly amber. If it’s too thick, it won’t flow through a pen nib or brush tip.
Add your carbon black powder to the shellac solution gradually, stirring as you go. Start with a small amount and test on paper. You want the ink dark enough to read easily but fluid enough to write with. If the ink is too thick, add more alcohol. If it’s too thin or pale, add more carbon. Once it dries on paper, the shellac film will trap the carbon particles in place, making the writing waterproof and highly resistant to fading.
Iron Gall Ink
Iron gall ink was the dominant writing ink in Europe for over a thousand years, used for everything from medieval manuscripts to the U.S. Constitution. It works through a chemical reaction rather than a simple pigment-and-binder system. Tannins from plant material react with iron sulfate to form a dark, insoluble compound that bonds directly to paper fibers.
The simplest version uses strong black tea as a tannin source. Brew a highly concentrated tea by steeping 5 to 6 tea bags in about half a cup of boiling water for at least 30 minutes. You want the liquid as dark as possible. Strain out any loose material.
While the tea steeps, prepare your iron solution. You can buy ferrous sulfate (sometimes sold as iron sulfate or copperas) at garden centers, where it’s sold as a soil amendment. Dissolve about a teaspoon in a quarter cup of warm water. Alternatively, you can soak steel wool in white vinegar for a week or two. The vinegar slowly dissolves the iron, creating iron acetate, which reacts with tannins in a similar way.
Combine the tea concentrate with the iron solution. The mixture will darken dramatically, often turning from brownish to blue-black within minutes. This color change is the key chemical reaction: gallic acid in the tannins binds with iron ions, and the compound oxidizes to form a dark, stable pigment. The resulting ink writes pale at first but darkens significantly over the next few hours as it oxidizes on paper.
Iron gall ink is water-resistant once fully oxidized, but it has a known drawback. The iron compounds are mildly acidic and can slowly degrade paper over decades. Adding a pinch of gum arabic (available at art supply stores) improves the ink’s flow and helps buffer this effect slightly. For documents you want to last generations, the carbon-shellac method is a safer bet for paper preservation.
Walnut and Oak Gall Variations
If you want to go fully traditional, oak galls are the classic tannin source for iron gall ink. These are small, round growths found on oak trees, caused by wasp larvae. Crush a handful of dried oak galls into a coarse powder, then simmer them in water for about an hour. Strain the liquid and combine it with your iron sulfate solution. Oak galls contain far higher tannin concentrations than tea, producing a darker, more permanent result.
Walnut ink takes a different approach. Boil the green or black outer husks of black walnuts in water for several hours until the liquid turns deep brown. Strain thoroughly and reduce the liquid by simmering until it reaches your desired darkness. Walnut ink on its own is not truly permanent. It’s essentially a strong natural dye without a binder. To improve its permanence, you can add a small amount of dissolved shellac or gum arabic. Even then, it will fade more than carbon or iron gall ink over time. Walnut ink is better suited for art and calligraphy where a warm brown tone matters more than archival permanence.
Tips for Better Results
The solvent you choose affects how the ink behaves. Alcohol-based solvents (isopropanol, ethanol) evaporate quickly and create inks that dry fast and resist water well. Water-based inks dry more slowly and are generally less permanent unless they rely on a chemical reaction like iron gall. If you’re making ink for use in a fountain pen, keep the mixture thin and well-filtered. Particles that are too large will clog the feed. Carbon inks in particular are notorious for clogging fine pen mechanisms, so use them with dip pens or brushes instead.
Store homemade ink in small, sealed glass containers. Alcohol-based inks will thicken as the solvent evaporates from an unsealed container. Iron gall ink can develop mold if left sitting for weeks, so adding a few drops of clove oil or a tiny amount of isopropanol helps preserve it. Shake or stir pigment-based inks before each use, since particles settle to the bottom over time.
For writing on non-paper surfaces like glass, metal, or plastic, the carbon-shellac formula works best. Shellac adheres to smooth, non-porous surfaces far better than water-based inks. You can thin the mixture further with alcohol for finer lines or thicken it for bold marks. On fabric, iron gall ink bonds well to natural fibers like cotton and linen, though it may wash out of synthetic materials without a mordant or heat setting.