The Science of Print: Relative Humidity

If you've ever visited Alexander's, you might notice an interesting feature in our printing areas. We keep running humidifiers in these areas. It turns out that paper, like people, needs to breathe. Paper absorbs and loses water equally, meaning that printers have to keep a careful balance of temperature and humidity. This is called relative humidity.

With the proper relative humidity, the paper neither gains nor loses moisture and stays in equilibrium. This is crucial because without it, we could not print on the paper at the quality Alexander's requires. Here's why we have to stay in the "Goldilocks zone" (i.e. "Just right") for our paper products.

Too Humid

Paper, under humid conditions, will suffer. The excess moisture in the air will wrinkle and wave the paper, making it completely unprintable. Ink will also stay wet longer, creating a higher risk for smearing or long wait times between print jobs.

Too Dry

When your press and storage rooms are too dry, your paper will lose moisture. This might not seem like as big a problem as damp paper, but it can ruin your stock just as easily. Stacked paper will lose its moisture from the edges, but not in the center. The paper will shrink on those edges, becoming uneven.

Paper packed too tightly in a dry area will also become brittle. Obviously, that reduces the quality of prints, and may mean that they won't make it through the printer smoothly.

Just Right

Under the perfect relative humidity, your paper will print and store safely. Plus, it has benefits after the paper's gone through the printer. Relative humidity can help the ink dry faster, keeping it from smearing on large, high-speed print jobs.

By making sure our printing facilities have the right conditions, we're making sure your print jobs are high-quality in every way. You can rely on our expertise to get the best printing we can offer, no matter the job.


Stay tuned: we're going to continue the Science of Print series! Follow us to learn more about the technical and scientific details of printing--and how it affects your business!

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