Watercolor paper warping is a common problem that can ruin the final look of your artwork. If you’ve ever found your carefully painted piece buckled and distorted after drying, you’re not alone.
Understanding how to fix watercolour paper warping can save your paintings from unwanted wrinkles and ripples.
This article will show you several effective methods to flatten your warped watercolor paper and prevent it from happening again.
From simple re-wetting techniques to using tools like a weight press or blotting paper, you’ll learn how to address warping at different stages of your painting process.
By the end, you’ll know how to stretch your paper properly, use the right materials like 300gsm watercolor paper, and handle your finished works to keep them smooth and flat. Let’s dive into practical steps to maintain your artwork’s integrity.
Choosing the Right Watercolor Paper to Prevent Warping
Paper Weight Matters
The most common mistake when starting with watercolor is picking the wrong paper weight. 140lb watercolor paper (300gsm) might sound decent, but if you’re applying multiple washes or working with a lot of water, it’s going to buckle.
Heavier paper, like 300gsm watercolor paper or 300lb cold press paper, handles moisture far better.
If you’re serious about avoiding warping altogether, you should invest in heavyweight cold press paper or even hot press paper, which lies flatter once it’s soaked and stretched.
Surface Texture
There are three main textures you’ll come across: cold press, hot press, and rough paper. Cold press, or not press paper, is the most forgiving, with a bit of texture that works well with most techniques.
Hot press paper, however, is smoother and may be ideal if you’re doing detailed work where buckling can distort precision.
Rough paper can be tricky; it absorbs water unevenly, making it prone to ripple and buckle if you’re not stretching it properly.
Watercolor Block for Minimal Warping
Using a watercolor block is another simple way to prevent warping. Blocks are glued on all sides, which helps hold the paper flat while you paint.
After you’re done, you can remove the sheet with a palette knife, and it should stay flat without much fuss.
It’s worth mentioning that pre-stretched paper also comes in handy for painters who don’t want to deal with taping or stretching their own paper.
Cotton Content
High-quality watercolor paper is often made from 100% cotton rag, which naturally handles water better than pulp-based options.
If you’re serious about avoiding warping, steer clear of wood pulp papers. They’re more prone to buckling, no matter what you do.
Investing in handmade watercolor paper might seem like an expense, but the durability and resistance to warping will save you headaches down the road.
Preparing Your Paper
If you’re using single sheets, not blocks, you’ll need to stretch the paper before you start painting.
Soak your paper in a tray of water for about 10 minutes, then tape it down to a plywood board or gatorboard using artist’s tape or art gum tape.
Let it dry completely before you begin painting. This process makes a huge difference, preventing buckling when you apply washes later.
Common Pitfalls to Avoid
- Avoid using thin, 140lb watercolor paper without stretching or taping it down. It will buckle under heavy washes.
- Don’t skip the stretching process if you’re using anything below 300lb paper. It’s tempting to get started right away, but skipping this step almost guarantees warping.
- Using the wrong texture for your technique—such as rough paper for fine details—can cause uneven absorption and ripple effects.
Preventative Techniques Before Starting to Paint
Soaking the Paper
The simplest way to prevent watercolor paper from warping is by soaking it before you even touch a brush.
You take a tray, fill it with water, and submerge the sheet for about 10 minutes. This saturates the fibers, allowing the paper to relax.
Once soaked, carefully lift it out—don’t tear it—and lay it flat on a plywood board or gatorboard.
Stretching with Tape
Here’s the critical part. Use artist’s tape or gummed tape to secure all the edges of the paper. You want to create tension so that as the paper dries, it stays taut.
The tighter the paper, the less chance it will warp when you start applying water and pigment.
Trust me, this step alone can save you from 90% of the warping headaches. Make sure the tape is sticking properly, or it’s pointless.
Drying Fully
This is where impatience ruins everything. You have to let the paper dry completely before you begin painting.
If it’s even slightly damp, the paint will cause it to buckle, and no amount of post-painting tricks will fix it.
Sometimes, I’ll leave it overnight if I’ve soaked the paper heavily. Some people use a hairdryer, but that’s a shortcut, and it often doesn’t dry the paper evenly.
Using a Watercolor Block
If you don’t want to go through the soaking and stretching process, you can just grab a watercolor block.
These are pre-glued on all sides, so the paper is already held flat. It’s convenient, especially for smaller works.
But if you’re working on a large painting or something more experimental, it’s worth going through the manual stretching process. Blocks are limited in size and flexibility.
Avoiding Thin Paper
Avoid 140lb watercolor paper unless you’re into warping. The thinner the paper, the more likely it will buckle under the weight of your washes.
Always aim for 300lb cold press paper or heavier. If you’re working with a lot of wet-on-wet techniques or heavy washes, nothing under 300lb will hold up without warping, even if you stretch it.
Common Pitfalls to Avoid
- Never tape paper that’s only partially dry—it needs to be fully soaked before you secure it.
- Don’t skip the soaking step if you’re using single sheets or thinner paper.
- Resist using makeshift weights like books to flatten your paper; they can create uneven pressure, leading to more warping.
How to Flatten Watercolor Paintings After Warping Occurs
Re-wet and Press Method
When your watercolor painting is warped, you can re-wet it to smooth it out. The goal is to lightly dampen the back of the paper without disturbing the paint on the front.
I use a clean sponge or spray bottle for this. Be careful—not too much water. Once it’s damp, lay the painting face down on a flat surface like gatorboard or a plywood board.
Next, place a blotting paper or absorbent towel on top to help soak up excess moisture. Then, stack heavy books or any flat, weighted objects evenly across the surface. Let it sit for a few hours, or even overnight. The paper should flatten as it dries.
Using a Weight Press
If you have access to a weight press, it’s the easiest way to flatten warped watercolor paintings.
A weight press applies consistent pressure, which is crucial for restoring the paper’s flatness without damaging the painting. Simply place the painting between two layers of blotting paper and let it press for several hours.
Ironing the Paper
Ironing is a last resort, but sometimes it works. Flip the painting over, so the back is facing you, and place a clean cloth between the paper and the iron.
Use the iron on a low setting, without steam. Slowly iron the back of the paper, working in small sections.
It can flatten the buckling, but there’s a risk of damaging the paper or paint if you’re not careful. Don’t press too hard, and always check the heat before starting.
Common Pitfalls to Avoid
- Don’t soak the paper too much when re-wetting; the goal is dampness, not saturation. Excess moisture can cause more warping or even damage the painting.
- Avoid using high heat when ironing. It can burn or distort the paper.
- Never rush the drying process—using a hairdryer might seem quick, but it usually leads to uneven flattening and further warping.
Additional Tips and Best Practices for Maintaining Flat Watercolor Paper
Use Proper Storage
Watercolor paper is sensitive to humidity and how you store it makes all the difference. Keep your unused sheets in a dry, flat environment, away from moisture.
If you’re using individual sheets rather than a watercolor block, store them between two heavy boards to keep them from curling over time. That prevents any issues before you even start painting.
Pre-Stretching the Paper
If you’re not using pre-stretched paper, take the time to soak and tape your sheets before beginning any project.
It’s annoying at first, but skipping this step leads to headaches when the warping starts. Make sure to secure the edges tightly with artist’s tape on a gatorboard or plywood board, ensuring it dries evenly.
Limit Excessive Water Use
Even the best paper will warp if you’re drowning it in water. Use just enough water for your techniques—whether it’s wet-on-wet or wet-on-dry—and don’t overdo it.
If the paper becomes too saturated, it’s much harder to prevent buckling, no matter how much preparation you’ve done.
Dry Flat, Not Upright
When you finish painting, avoid propping the artwork upright to dry. Always dry your painting flat to keep the moisture from pooling in one area, which inevitably leads to ripples.
Lay it on a flat surface or use a drying rack designed for watercolor paintings. It’s one of the most overlooked steps but crucial for keeping your work flat.
Avoid Direct Heat
If you’re impatient (which I get, honestly), you might be tempted to use a hairdryer to speed up the drying process. Don’t.
Direct heat warps the paper by drying certain sections faster than others, creating uneven tension across the surface. Let it dry naturally. If you must speed things up, use a fan for airflow rather than heat.
Common Pitfalls to Avoid
- Using low-quality paper—avoid anything less than 300gsm watercolor paper if you want minimal warping.
- Forgetting to stretch thinner paper or assuming a watercolor block is always enough for larger works.
- Storing paper in humid areas; moisture in the air can start the warping process before you even paint.
FAQ on How To Fix Watercolour Paper Warping
What causes watercolor paper to warp?
Watercolor paper warps because it absorbs water unevenly. As the paper dries, the fibers contract, creating tension that leads to buckling.
140lb watercolor paper is more prone to this because it’s thinner. Heavier paper, like 300gsm watercolor paper, resists warping better, but stretching helps reduce this issue.
Can you fix warped watercolor paper after painting?
Yes, you can fix warped watercolor paper by re-wetting the back of the paper. Once damp, press it under a heavy, flat surface, like a stack of books, or use a weight press.
Let it sit for a few hours to flatten the paper without damaging the artwork.
Should I stretch watercolor paper before painting?
Stretching is critical, especially if you’re using thinner paper like 140lb watercolor paper. Soak it in water for 10 minutes, then tape it down to a plywood board.
Let it dry fully before painting to prevent warping during the painting process. It keeps the paper taut and flat.
What’s the best paper weight to prevent warping?
For minimal warping, use 300gsm watercolor paper or heavier. 300lb cold press paper holds up under heavy washes without buckling.
Thinner paper warps easily, especially under wet-on-wet techniques. Always stretch thinner papers to prevent problems down the line.
Can I use a hairdryer to speed up drying?
It’s better not to. Using a hairdryer creates uneven drying, which causes more warping. Always let the painting dry naturally in a flat position to prevent buckling.
If you’re in a hurry, use a fan instead. Heat will only make the warping worse in most cases.
How long should I leave the paper under weights?
Leave the paper under weights or in a weight press for at least several hours, preferably overnight. This ensures the paper dries evenly and flattens properly.
Be patient; rushing this step can leave you with partially warped areas, ruining the effort you’ve put in.
Can I iron watercolor paper to flatten it?
You can, but be cautious. Iron the back of the paper with a clean cloth between the iron and paper. Use a low setting, no steam, and work in small sections.
It’s risky because too much heat can damage the painting or paper, so it’s really a last resort.
How can I prevent warping when painting large washes?
To prevent warping with large washes, work on pre-stretched paper or a watercolor block. Use consistent, even strokes and avoid oversaturating the paper.
Working with high-quality cotton rag watercolor paper also helps because it absorbs moisture evenly, reducing the chances of buckling.
Can I use tape to flatten warped watercolor paper?
Yes, but only in combination with re-wetting the paper. After dampening the back, tape down all edges to a gatorboard or plywood board.
Once it’s fully dry, the paper should remain flat. Taping by itself won’t fix the warping; it’s the moisture that helps realign the fibers.
What happens if I don’t flatten the paper?
If you don’t flatten the paper, it will likely buckle more over time. Warped watercolor paper can affect framing and overall presentation.
The ripples also distort the paint’s appearance, especially under glass. It’s best to address warping early to maintain the quality of your artwork.
Conclusion
Knowing how to fix watercolour paper warping can make a significant difference in preserving the quality of your artwork.
Whether it’s re-wetting and pressing, using a weight press, or carefully ironing the back of the paper, you now have several reliable methods to correct warping after it happens.
Stretching the paper beforehand, especially if it’s 140lb watercolor paper, is essential for preventing future issues.
Using proper drying techniques, avoiding excessive water, and selecting high-quality materials like 300gsm watercolor paper will help maintain flat, smooth surfaces for your paintings.
The key is preparation and patience. Taking the time to stretch, tape, and dry your watercolor paper properly will save you the frustration of dealing with buckling later on.
These steps, combined with careful flattening techniques, ensure that your watercolor work remains professional and ready for framing without the unwanted ripples.
