Why Your Print Corners Curl and How to Stop It
By Jacqueline Colley Illustration | Published: 2026-10-17
Category: Tips & Care
Learn why print corners curl, from humidity to storage methods, and get practical steps to flatten and prevent curling for good.
Quick answer
Print corners curl mainly because of moisture imbalance: paper fibers absorb or lose humidity unevenly, causing the edges to warp. The fix is to store prints flat in a cool, dry environment, ideally in a portfolio box or between boards, and to avoid direct sunlight or damp rooms.
What causes print corners to curl?
Paper is hygroscopic, meaning it naturally absorbs and releases moisture from the air. When the air is humid, the edges of a print take on moisture faster than the center, expanding slightly and causing the corners to curl downward. In very dry conditions, the opposite happens: the edges lose moisture and curl upward.
Other common culprits include storing prints upright without support, leaning them against a wall, or placing them in a frame without a backing board. Even the printing process itself—especially with Risograph or screen printing—can introduce slight tension that later shows as curling.
How to fix curled print corners
For mild curling, place the print between two clean, heavy books on a flat surface for 24–48 hours. Add a sheet of acid-free tissue paper on each side to protect the surface. If the curl persists, lightly mist the back of the print with distilled water (from at least 12 inches away) before pressing—this rebalances the moisture evenly.
For stubborn warping, you may need to humidify the print in a sealed container with a damp sponge for a few hours before pressing. This is riskier, so test on a less valuable print first. If the paper feels brittle or the curl is extreme, consult a professional conservator rather than attempting a DIY fix.
Best practices for flat print storage
Store prints flat in a dedicated print portfolio box or a shallow archival box. Keep them in a room with stable humidity (ideally 40–50% relative humidity) and away from radiators, air conditioning vents, or exterior walls. Avoid attics, basements, and bathrooms, where humidity swings are common.
If you must store prints vertically, place them in a rigid folder or between two sheets of acid-free foam core board and secure them with a strap. Never store prints rolled for long periods—this can set a permanent curl that is very hard to reverse.
Diagnosis: Is your print curling fixable?
- Symptom: One or more corners lift away from the surface when the print is laid flat. The curl may be mild (a few millimeters) or severe (the print forms a tube). Check if the curl is uniform across all corners or just one—this hints at the cause.
- Likely cause: Uneven moisture exposure. Humid room, direct sunlight, or storage upright without support are the most common triggers. Paper type matters too: thin or recycled papers curl faster than thick art papers. If the curl appeared after moving the print to a new room, the humidity change is the culprit.
- Corrective action: Press flat between heavy books for 24–48 hours with acid-free tissue layers. For stubborn curls, lightly mist the back with distilled water before pressing. If the paper feels brittle or the curl does not improve, stop and consult a conservator. Most mild to moderate curls flatten within two days. If not, the paper may have taken a permanent set.
- When to stop or choose another option: If the print has visible creases, tears, or the paper feels fragile, do not attempt to flatten it yourself. Consider framing it with a deep mat that holds the print flat behind glass, or store it in an archival box and accept the slight curl as a characteristic of the material. Framing with a mat can hide minor curling and protect the print from further damage.
Prints that stay flat with proper care
- A5 Small but so Spicy!: Risograph printed in the UK using Orange, Green and Sunflower inks on paper made from 80% recycled coffee cups. Recycled coffee cup paper can be slightly more prone to curling than standard art paper because of its mixed fiber content, so storing it flat in a stable environment is especially important to keep the corners down.
- A6 Aquarius Zodiac: Risograph printed in Neon Pink, Orange and Green on FSC Paper. FSC-certified paper is generally well-calibrated for printing, but the Risograph process can leave the paper slightly wavy if not stored flat immediately after purchase. A portfolio box or heavy book press will help it settle.
