How Do Markers Work?

Science fiction writer Arthur C. Clarke wrote, “Any sufficiently advanced technology is indistinguishable from magic,” and while Clarke’s Third Law probably wasn’t about artist’s markers, when we look at all the amazing things fiber-tipped markers can do, and the combination of engineered materials and science behind them, markers really do seem magical!

One amazing property of markers is that they seem to defy gravity. Color flows upside down, sideways, and in any direction the artist holds them. They aren’t pressurized, and the ink isn’t sucked out like a siphon, because either of those would make the ink leak into the cap or spill. Marker ink flows by capillary action, the way plants take up water. The secret of why this works in markers is in the tips, and the physics that makes liquid flow through small spaces.

Markers feed ink through capillary action, a mysterious process that occurs when liquid moves seemingly all by itself. It takes a difference in pressure to move fluid through a larger space, like a pump to create pressure or vacuum, but in a smaller space, surface tension and adhesion allow liquid to move against the force of gravity. In the case of markers, that space is inside the tip. Marker nibs are made of fibers pressed together tightly enough for ink to creep and crawl through the spaces between.

Markers wouldn’t feed if the tips just soaked up the ink, so synthetic fibers are just right for the job. The first marker tips were natural materials like wool felt and bamboo fiber, but for decades they have been made of engineered synthetics like polyester, acrylic, and even ceramic, materials that don’t absorb ink internally. But markers still wouldn’t work if the ink didn’t have just the right properties.

Image (left): Early marker patent diagrams, including (left) the very first marker, the “fountain paintbrush”

Marker ink needs to be thin enough to flow, but still has to carry a huge load of concentrated color, plus resin to hold it to the artwork. The dyes used are modern inventions, centuries newer than many artist’s pigments. Synthetic-organic colorants are intense, staining dyes, soluble in a number of carrier solvents. Marker ink solvents have changed over the years to make them safer and perform better, but they still have to be thin and dry fast enough for the resin binders. Manufacturers reformulated to use alcohol and even water as carriers, eliminating strong odors and health risks associated with the powerful solvents some 1st generation pens used decades ago.

Image (right): Marker advertisements, mid-20th century

Paper designed to make the most of markers brings out the full brilliance and fluid handling of the medium. Marker papers are smooth and bright white, with a coating that keeps ink from soaking the fibers. This lets light reflect back through like stained glass, and facilitates smooth, gliding movement of the tip. Using good marker paper instead of ordinary sketch paper like newsprint conserves ink and makes your pens last longer.

An additional, amazing fact about markers is that they can be refilled again and again, because the engineered materials used to make the tips don’t clog like an absorbent, natural material might. Blick Studio Markers and other great brands let you pull out the tips and replenish the ink supply, so you can bring your favorite pens back to life again and again. Synthetic marker nibs last a long time if kept moist and free from physical damage. And, if they do dry out or get worn, soaking the tips in denatured alcohol and replacing them with the worn end inside the marker body can even give a second act to worn-out nibs… just like magic!