Science

What's Inside Blue Ballpoint Pen Ink?

Fatty acids, alcohol, and some other not-so-magical ingredients.
  • 01
    Ballpoint pen patents go back to the late 1800s, but it took half a century to perfect those smooth blue lines that have come to define our notes and doodles.
  • 02

    Synthetic Dyes

    A cocktail of colorants is required for quality, fast-drying inks. The formula is heavily guarded, but it likely contains phthalocyanine blue, crystal violet—which was used in WWI to treat infections—and Prussian blue, a longtime favorite of painters.
  • 03

    Phenoxyethanol/Benzyl Alcohol

    For the dyes to work effectively, they need to use one of these two compounds as a carrier. Benzyl alcohol is a sweet perfume produced by fruit and phenoxyethanol, and it’s used in everything from bug repellant to antiseptics.
  • 04

    Alkyl Alkanolamide

    Dye can’t stick to paper on its own—it needs surfactants like alkyl alkanolamide to help lower the surface tension so it can sink into that Post-it note before the ink dries.
  • 05

    Oleic Acid

    No one wants ink gunking up the pen’s brass point. This fatty acid lubricates the ball, making sure it’s always ready to roll.
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