You’ve measured. You’ve logged. You’ve stirred. And somehow… your print’s still off. Welcome to the club. Viscosity doesn’t always shout at you—but it always leaves clues. And if you’re not catching them early, you’re just babysitting bad ink. Let’s walk through what to watch for—and how to fix it without stopping the entire shift.

What Bad Viscosity Looks Like in Real Life

It rarely shows up on a gauge. It shows up in your print:

  • Ghosting or light areas
  • Ink streaks or lines that weren’t there on the last job
  • Pinholes caused by foaming
  • Ink drying too fast on the anilox
  • Blown color—especially on high-speed jobs

If you’ve got operators blaming the substrate and ink techs blaming the press, chances are—you’ve got a viscosity issue.

First Things to Check (Before You Panic)

Viscosity problems can come from ink, air, equipment—or all three. Here’s your field checklist:

  • Stir the ink again—fully. Don’t assume it stayed stable.
  • Recheck viscosity with a clean Zahn cup. If you don’t have a stopwatch out, now’s the time.
  • Look for foam—especially with fresh or high-speed ink recirc.
  • Check pH (for water-based inks)—too low and ink thickens.
  • Inspect the lines—clogged or partially dried return lines can throw off your delivery.

Adjusting On the Fly (Without Making It Worse)

You don’t always need to shut down the press. In many cases:

  • Add small amounts of extender—slowly and consistently
  • Watch temperature and humidity—these can shift viscosity mid-run
  • Monitor pH drift throughout long jobs
  • Run short bursts to test before going full-speed

The goal isn’t perfection—it’s stability. If you can keep your viscosity consistent, everything else gets easier.

It’s Not Just an Operator Problem

Viscosity issues can start at any point—formulation, temperature swings, bad data handoff, or even just someone rushing through morning setup. Encourage cross-shift communication. Build SOPs that include drain time, pH, and environment notes. Keep it simple, but clear.

Smarter Pressrooms Spot It Early

You don’t need to be fancy. Just consistent. When viscosity’s off, you’re wasting time, product, and patience. But when you know what to look for—and how to fix it mid-run—you stop losing hours and start gaining control.

Pro tip: Always run with a disposable drip tray under your ink station—just in case viscosity issues cause accidental ink drips or spills. At DIPCO, we’ve got drip trays for just about every press model out there. Need help finding the right fit? Give us a call at 970‑874‑2852 or shoot us an email—we’re happy to help you get set up before the next run even starts.