How to Flatten a Poster: 5 Easy Methods

How to Flatten a Poster: 5 Easy Methods (Without Damaging It)

First published: 9 December 2021| Updated: 6 August 2026

The quickest way to flatten a rolled poster is to lay it flat, image-side down, under evenly spread weight for 24 to 48 hours. If you’re short on time, reverse-rolling or popping it straight into a frame both work well, too. Below are five tried-and-tested methods, plus guidance on repairing any creases or tears along the way.

Method	Time needed	Risk level	Best for
Weigh it down	24-48 hours	Low	Most posters, no special kit needed
Reverse-roll	A few hours	Low	Light curling, no creases yet
Frame it	Minutes (curl flattens over time)	Very low	Posters going straight on display
Steam	10-15 minutes	Medium	Stubborn curls, quick turnaround
Low-heat iron	15-20 minutes	Higher	Wrinkles that won’t budge with weight

Method 1: Weigh It Down

The simplest option. No special equipment, just patience.

Unroll the poster and lay it image-side down on a clean, flat surface.
Place a heavy, flat object on each corner, books, magazines, or plates all work. For extra protection, slip a sheet of mat board or craft paper between the poster and the weights.
Leave it flat for at least 24 hours. Stubborn curls may need 48 hours or another round.

Method 2: The Reverse-Roll

If your poster is curled one way, rolling it the opposite way can undo it.

Unroll the poster and lay it image-side down.
Roll it in the opposite direction to how it arrived.
Secure with a rubber band (avoid tape; it can tear the paper when removed).
Leave for a couple of hours, then unroll. Repeat if it’s still not lying flat.

Method 3: Frame It Straight Away

Framing flattens as it protects, so it’s a two-birds option if you’re ready to display the poster.

Unroll the poster and get a frame matching its dimensions.
Open the back of the frame and place the poster inside, image-side down, against the glass.
Secure the backing and hang the frame level. The pressure inside gradually flattens the poster.

Method 4: The Steam Method

Good for stubborn curls when you need a faster fix than weighing them down overnight.

Hang the poster in a well-ventilated bathroom.
Run a hot shower for 10 minutes to gently humidify the room (keep the poster away from direct water or spray).
Move it straight to a flat surface afterwards and weigh it down for an hour or two to set it flat.

This works by relaxing the paper fibres, so avoid it on posters with delicate coatings, foil elements, or vintage/brittle paper stock.

Method 5: Low-Heat Iron

The fastest fix, but also the riskiest, since it combines heat and moisture on paper.

Lay the poster image-side down on a flat, heat-safe surface.
Cover it with a dry bath towel.
Lightly dampen the towel with a spray bottle, not soaking wet.
Set your iron to its lowest heat setting and press gently through the towel.
Stop if wrinkles persist rather than increasing the heat.

Why Do Posters Curl in the First Place?

Paper has “memory.” When it’s rolled tightly for shipping, the fibres inside the curl compress while the fibres outside stretch slightly. Once unrolled, the fibres try to spring back to that rolled shape, especially in the first few weeks after printing, when the paper hasn’t fully settled.

Humidity makes this worse, since damp air makes fibres more flexible (which is exactly why the steam method above works), while dry air can make paper brittle and prone to cracking along the curl. Understanding this is key to picking the right method: gentle, gradual pressure relaxes the fibres safely, while forcing a stubborn curl flat too quickly causes creases and cracks.

Choosing the Right Method for Your Poster Type

Not all posters behave the same way, so it’s worth matching the method to what you’re actually flattening. Banana Print’s standard posters are printed on 170gsm or 350gsm silk paper (including a 350gsm recycled option) for CMYK prints, or a 200gsm satin stock for our 6-colour latex prints up to A0, both of which respond well to any of the methods above without special handling.

Standard matte or gloss paper posters (the most common type): all five methods above are safe. Weighing down or reverse-rolling is the safest starting point.
Foil, Spot UV, or metallic-ink posters: avoid the iron-and-steam method. Heat and moisture can lift or dull foil and metallic finishes. Stick to weighing down, reverse-rolling, or framing.
Canvas prints: canvas doesn’t respond well to being weighed down flat; it’s more likely to crease along fold lines. Instead, gently reverse-roll around a wide tube, or have it stretched onto a frame, which is the standard way to flatten canvas permanently.
Vinyl banners and outdoor signage: these are more flexible than paper and usually relax on their own once hung or displayed flat for a few hours. Avoid ironing vinyl, as heat can warp or melt it. See our guide to banner materials if you’re deciding between paper and vinyl for your next order.
Vintage or older posters: brittle, aged paper is prone to cracking rather than creasing. Skip heat and moisture entirely, and use the gentlest method (weighing down with a longer timeframe) or seek a professional framer for anything of real value.

Poster Still Curling? Troubleshooting Common Problems

It’s Been 48 Hours, and It’s Still Curling

Some posters, especially ones rolled tightly for a long time in transit, need longer than 48 hours. Leave it under weight for another 24 hours, or combine methods, for example, reverse-roll it first, then weigh it down.

Only the Corners Are Curling, Not the Middle

This usually means the weight isn’t reaching the edges. Add extra weight directly to each corner, or place a flat board on top of the entire poster rather than a few books, so pressure is even across the entire surface.

The Poster Is Cracking, or the Ink Is Flaking Where It Was Rolled

This is a sign that the paper or ink has dried out and become brittle. Stop immediately, and don’t force it. A very light steam treatment can help re-introduce some flexibility before trying again, but proceed carefully and test on a corner first.

It Flattens but Curls Back up Again After a Few Days

The fibres haven’t fully relaxed yet. This is common with posters that were rolled for a long time before you received them. Repeat the weighing-down method for a longer period, or frame it, since the ongoing pressure inside a frame keeps it flat permanently.

Common Mistakes to Avoid When Flattening a Poster

Using too much heat, too fast. A hot iron on full setting is the single biggest cause of scorched or warped posters. Always start on the lowest setting.
Skipping the protective layer. Ironing or steaming directly onto the poster (without a towel or barrier) risks direct heat damage and shine marks.
Using tape directly on the poster to hold it flat. Tape can tear the paper on removal and leave residue. Use rubber bands or weights instead.
Giving up too early. Most posters need at least 24 hours under weight. Checking after ten minutes and concluding the method “doesn’t work” is a common reason people move straight to riskier methods unnecessarily.
Storing a flattened poster rolled back up. Once flat, keep it flat (or framed); rolling it again undoes all the work.

How We Package Posters at Banana Print (and How to Reduce Curling Before It Starts)

Every poster we print in-house goes out rolled around a wide-diameter core and wrapped inside a rigid postal tube, rather than folded, which is what causes the sharp creases you can never fully remove. Using a wider core means a gentler curl to begin with, so it flattens out faster and with less risk once it arrives with you.

If you want to make flattening even easier, unroll your poster as soon as it arrives rather than leaving it rolled up for weeks. The longer the paper sits rolled, the more its fibres set into that shape, so getting ahead of it early makes any of the five methods above work faster.

Got a Torn or Wrinkled Poster? Here’s How to Fix It

If a stray crease or small tear has crept in, you can usually rescue it without further damage:

Archival tape for small tears. It won’t yellow over time and lifts off cleanly with a little heat or moisture if needed.
Professional backing, fixing the poster to the board or foam, which straightens out existing tears as part of the process.
Japanese paper patches, a tissue-and-wheat-starch-paste technique that’s one of the oldest tricks for repairing tears invisibly.

Keeping Your Poster Looking Its Best Long-Term

Frame it. A frame is the single best protection against dust, moisture, and accidental damage.
Skip the tape, tacks, and nails. Acid in the tape and holes from pins damage the paper over time. Use archival tape if you need to mount it temporarily.
Keep it out of direct sunlight, which fades and yellows prints faster than almost anything else.
Store rolled posters in a plastic sleeve in the dark to protect the edges and prevent further fading or creasing.

FAQs

How long does it take to flatten a poster?

Weighing it down takes 24 to 48 hours for most posters. If you need a faster result, reverse-rolling takes a couple of hours, and the steam method can flatten a stubborn curl in under 20 minutes.

Can I flatten a poster without an iron?

Yes. Weighing it down, reverse-rolling, framing, or using steam from a hot shower will all flatten a poster without using an iron.

Will flattening damage my poster?

Not if you use the right method for your poster type. Weighing down and reverse-rolling carry the lowest risk. Heat and moisture-based methods (iron, steam) work faster but need more care, especially on delicate, foiled, or vintage paper stock.

What’s the quickest way to flatten a poster?

The steam method is usually fastest, flattening a curl in 10 to 20 minutes. For a no-risk option, framing the poster straight away also works immediately as pressure builds inside the frame over time.

How do I stop my poster from curling back up?

Keep it flat under weight until the curl has fully released, not just until it looks flat. Framing it afterwards is the best way to keep it flat in the long term.

Print Your Own Posters at Banana Print

Ordering a new poster? At Banana Print, our poster printing is produced in-house from £9.95 on 170gsm or 350gsm silk paper (including a recycled option), or on 200gsm satin stock up to A0 if you need a larger 6-colour latex print. Standard orders are dispatched within 24 to 48 hours, with next-day delivery from £4.95. Upload your own artwork or design online, and we’ll take care of the rest.

Not sure what to put on it yet? Take a look at our guide to standard poster sizes and design, or our tips for effective poster design, before you order.

Posted in Printing Talk