Why Watercolor Paper Curls – And How to Prevent It

There are many different types of paints that an artist can use to create something amazing. Watercolor paints are a lot of fun and give a unique look to your work, but they present some additional issues because they are based on water. The biggest issue is that the paper you use for painting may curl and warp, ruining your picture. 

Watercolor paper curls due to low-quality paper, not stretching the paper before use, too much saturation, and not giving the paper enough time to dry after painting. Stretching the paper out before you begin and picking a heavier-weight paper is the best way to prevent watercolor paper curls. 

In this article, we will take a look at what watercolor paper is, why the watercolor paper is likely to curl and warp, and some of the steps you can take to prevent this curling, both before you even start painting and when the painting gets ruined after you are done. So here it is: Why Watercolor Paper Curls – And How to Prevent It.

What Is Watercolor Paper?

Watercolor paper is a type of artists’ paper created to help hold onto the watercolor medium. It will usually have a special type of treatment that helps make it less absorbent, preventing the paint from bleeding and muddling together on the paper. 

There are several different styles and grades to choose from. Each will give a different result to your final picture. You may need to experiment a bit to see which type you like the best. 

Factors to Consider When Choose Watercolor Paper

There are three important components for their impact on the feel and look of the watercolor paper:

• The treatment used on the paper
• How the paper is processed after manufacturing
• The weight of the paper

You need to consider all three when selecting the paper you want to use. In addition to those three factors, consider that watercolor paper comes in different sizes and is available inbound and loose forms. The paper is also available in a watercolor block. This is simply a block with the paper glued down on all sides, allowing you to have an easy and portable clipboard of paper to use. 

How Is the Paper Treated?

Most watercolor paper will be treated with gelatin. This coats the fibers of your paper so they won’t take on the water as quickly as other types of paper. When the gelatin gets mixed with the fibers before making the paper, this tends to be of higher quality. Sometimes the manufacturer will paint the coating on later. This is not always a big problem but can turn into one of the artist’s gouges or scratches on the paper. 

Some companies will also hand form the paper using paper screens. When the paper is then pulled from the screen, the deckled edges will be created on the sides of the paper. These become wavy and soft. Some artists prefer these, though the waves may impact the quality of the paper. 

The Processing Technique

Watercolor paper that is well labeled will indicate what kind of processing technique is used. Several processing techniques are depending on the type of paper and the quality. You will be able to choose between rough, cold-pressed, and hot-pressed, with rough being the highest quality. 

The Weight of the Paper

There should also be information on the weight of the paper, which is important when you want to prevent curling and warping. Weight will be determined by the combined weight of 500 sheets of that type of paper. 

Heavier watercolor paper is less likely to warp and curl. However, this paper will need to be stretched out before use, or it does buckle. We will look at how to do this simple process, so it is fine to purchase the heavier stock. 

It is best to use watercolor paper any time you plan to use watercolor paints. It is possible to try using them on regular paper, but this paper will curl up and warp with even a little paint. Watercolor paint, especially the heavier and textured varieties, is better to use. 

Why Does Watercolor Paper Curl?

There are several reasons why your watercolor paper may curl and warp while you are painting. Knowing what is causing the paper to curl and learning how to prevent it can help you get the perfect painting. Some reasons why your watercolor paper is curling includes:

Low Paper Quality

The thin paper will easily get oversaturated and cause issues with curling and warping. The heavier the paper you can purchase, the less likely this will happen. While you may want to choose a little lower quality for practicing, the lower you go, the more likely the paper will curl and wrap for you. Pick a higher quality paper, like the ARTEZA 9X12” Expert Watercolor Pad, to help strike a balance between budget and quality. 

Too Much Saturation

Too much saturation may cause your watercolor paper to curl and warp. Whether you use paints with too much water, add too much water to the painting on purpose, or spill water on the canvas, this extra saturation can cause some curling. Only use the minimal amount of water you need to prevent oversaturation in your painting. 

Not Enough Time to Dry the Paper

After painting, it is important to give the paper time to dry completely before moving it around or storing it. Eight hours is the minimum, though you should always double-check that the paint is dry and give it longer if necessary. Consider giving it 24-hours or longer to get the paint time to settle and dry. 

Bad Watercolor Paints

Some watercolor paints are better than others. Some may contain more water than others, making it harder to prevent curling in your paper. Finding some high-quality paints, including these pastel PHOENIX Watercolor Paint Set, can help get pictures that look amazing while keeping your paper straight. 

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How to Prevent Watercolor Paper From Curling and Warping

We need to follow a few steps to ensure that our watercolor painting comes out perfect without curling or warping. Some of the steps we can use include:

Pick the Right Paper

The type of paper used during the painting will make a big difference. Heavier is always better when it comes to choosing the type of paper, and having some texture is important as well. Working with regular printer paper will result in a mess, while high-quality watercolor paper is much better. 

A few things to consider when picking out paper include:

The Form

There are some high-quality watercolor paper choices out there. If you are a beginner, though, you most likely don’t want to purchase the most expensive paper out there. You want to work with some that won’t curl and will last but is inexpensive enough that you can get in lots of practice. Find a good balance between quality and budget to find the right paper. 

The Weight

The heavier the paper, the better it will hold onto the paints. This is determined by weighing 500 sheets of paper in its uncut state. The weight will also indicate the price and quality of the paper. 

There are many different grades of a paperweight. The higher the weight, the higher the quality. This can cause the price to go up as well. Finding a good balance to keep costs down is important. 

Some typical weights for watercolor paper include:

• 90-pound paper is considered the student grade. It is thin and more likely to buckle. This is a type you should avoid. 
• 140-pound paper is a good choice. It is much thicker than the lighter types and is thick enough to stretch out as needed without buckling. 
• 300-pound is similar to a board. It won’t require you to stretch it out, but it will cost twice as much as the other types. 

Finding a good weight between 140-pound and 300-pound can help your watercoloring become more cost-efficient. 140-pound paper is perfect for practicing your watercoloring. 

The Texture

There are several types of texture that you can use based on the type of picture that you would like. These include the hot-pressed, cold-pressed, and rough paper. 

Hot-pressed is generally agreed not to be as good as the others. It is smooth and hard and won’t handle the different watercolors that you want very well. 

Rough paper is seen as the best because the texture is thicker and can handle more paint without issues. Some artists do not like this texture, so it is important to experiment and see if it is right. 

Cold-press is not necessarily as good as rough but can be a good alternative between the hot-press and rough paper. It has a better texture while still being able to hold onto the watercolor paint a bit better. 

Stretch the Paper

There are several methods we can use to help stretch out the paper we want to use. The easiest and least likely to cause damage is to use a bit of water to pre-soak the paper and then tape it down to dry before painting. This may leave a little border around the edges of your painting but helps keep it flat while it dries. 

Other methods can be used as well. Attaching your watercolor paper to a board or using a canvas stretcher may work as well. We will explore each of these, concentrating on the soaking paper method to help you learn how to use these methods. 

Soak the Paper

Find a clean plastic tub or another container and clean it out well. If you leave anything inside, that could attach to the paper and ruin it. Four inches of water should be enough. Coldwater is the best for this, and you can use tap water too. Cool water will help the paper keep the same size. Sizing can reduce the absorbency of the paper so your paint won’t soak through. 

Take your piece of paper and fully submerge it in the water. Keep it as straight and even inside the water as possible. After the paper has a few minutes to get wet, you can slowly pull it out. Allow the paper to hang over the tub, letting some of the excess water drips off. 

After removing the paper from the water, place it on a flat and clean surface to dry. We will attach some painters’ tape to keep it flat as it dries in the next step. 

Attaching the Paper to a Canvas

A canvas stretcher is simply a wooden frame that is either square or rectangle. You will use this method to help staple the watercolor around it and make it longer. The canvas stretcher you choose should be just a little smaller than the paper you plan to stretch out, so it has room to grow. 

This process is pretty simple to work with. Place the paper down on a flat surface and then center the canvas stretcher as close to the middle as possible. Do one side at a time and fold the sides of the paper up and over the side of the canvas stretcher. Add a staple every inch or so, leaving some room on the corners. 

Do this for the other three sides and then lay the whole thing down flat somewhere for a few hours. Then it is time to pull out the staples and get to work painting!

Attaching the Paper to a Board

If you happen to have a board around, this is a good option. Any board type, even foam core, will work. You want to pick out something slightly bigger than the piece of watercolor paper you plan to stretch. A traditional drawing board, plywood, or another surface will work fine. 

This is where the hard part comes in. Using your hands, stretch and smooth out the paper. You do not need to pick up the paper at all to do this. Start in the middle and move them out to the sides. It won’t make drastic changes but can help to make the paper a little longer. 

You can choose to then put this down with some tape or staples so it has time to dry. This will take at least a day. Once the paper is dry, it is time to trim the tape’s inner edge, saving it to use next time. You can also pull out the staples and slice the edges of the paper to make it smooth. 

Tape It Down

All three of the methods above can be useful when it is time to stretch out your paper. Stretching the paper makes it easier to add the watercolor paints without absorbing too much and ruining the paper. 

Once the paper is stretched, it is time to tape it down. Find a flat and clear surface to work with, preferably in the same spot you plan to paint on to avoid moving. Get some painters’ tape and add a strip to each side, taping half onto the watercolor paper and half onto the flat surface so the paper doesn’t move. 

If you worked with the stretching method that got the paper wet, then you will need to leave the paper in this position for eight hours minimum. This gives the paper time to dry off. For the other two methods, you can move on to the next step once the tape is in place. 

Start Painting

Now it is time to paint. You can paint the paper however you would like. Keep in mind there will be a small border around the watercolor paper due to the painters’ tape. The size of this will depend on where you placed the tape.

Thanks to the stretching technique, the paper should hold onto more water and paint than before. And if you went with a higher quality paper that was thicker, you should be set to go with painting any masterpiece you would like. 

Give It Time to Dry

Once your painting is done, you need to give the watercolor paints some time to dry. The amount of time you need for this will depend on how much paint you used and how much water was in the paint. If you remove the paper before the paint completely dries, your paper will start to curl again. 

It is often recommended to leave the painting overnight. Double-check the paper to see if it is dry, rather than assuming, so you don’t ruin the picture. 

If you need to hurry this process up a bit, it is possible to use a fan or a blowdryer to help. If you choose to use this method, only use the low setting. It is easy to become impatient, but the hot temperature on your blow dryer will quickly ruin your painting, and it isn’t worth the effort. Air drying is the best option, though. 

After the painting has had time to dry completely, you can remove the painter’s tape. You can then choose to leave the slight border or use a crafter’s knife to slice them off to finish the painting. Frame the painting and hang it somewhere you can enjoy your own handiwork. 

How to Flatten Watercolor Paper After Painting

In the above section, we spent some time looking at the basics of treating our watercolor paper to ensure it won’t curl while we paint or even while the picture is drying. This works well if you haven’t started the painting. 

However, if you have already finished the painting and the paper is a curling or have a painting that accidentally got water on it and is starting to warp, you most likely need a new method to help flatten the paper and make it look nice again. 

The good news is there are a few steps you can use to help flatten your watercolor, even after painting. This can help get the painting back to its original beauty without making it worse. 

Using Water

The most common way to flatten your paper without potential burning or other issues is to use water. You will need a few books, a spray bottle or a sponge, and some patience to get all of this done. 

Find a clear area on a desk or counter where the paper will not be in the way for a few days. Take a spray bottle with some water or a damp sponge, and lightly mist the paper. We don’t want the paper to be overly wet, but a little wet. 

Lay down some sketch paper on the clean surface, the paper on top, and another piece of sketch paper over this. Try to keep them as flat as possible. When this is set up, you will need to add something heavy on top of the paper. Books are often the best and easiest choice to go with. 

Then, it is time to wait. After two hours, you can remove the weight and replace the sketch paper if it is wet. Repeat this every few hours until the sketch paper is dry when you check a few times, which may take one to two days to complete. 

While it does take some time to complete, you will notice that your watercolor paper is flat and back to normal!

Using an Iron

This approach is often not recommended because it is easy to get the temperature too hot and ruin the painting. If you are in a bind or the water method did not work, this may be a good option for you. 

Before you start, make sure you have a towel that you can use. Never have the iron go directly on top of the painting, or it will get scorched. You want the painting directly on a flat and clean surface. Spray a little mist of water on top, and add a towel over it. 

Then, bring out your iron. The goal is to have the iron at the lowest setting possible. If your iron does not go down to a lower setting, do not use this method. Gently rub it over the entire surface of the paper, adjusting the heat just a bit. The water that is on the back should help to relax the crumpled fibers of the paper. 

When the paper appears to be pretty flat, take the iron and put it away along with the towel. Add another towel or some sketch paper back on top and about 25 pounds (11.3 kg) of books over it all. Walk away. 

After two hours, check to see if the sketch paper is damp and replace it with a new one. Keep this going until the sketch paper is no wrinkling or damp any longer, which will take a few days to complete. When you are done, your watercolor painting should look as good as new. 

For a video showing how some of these would work, click on the below, where Makoccino shows what they do when their watercolour paper buckles, or becomes wavy before, during, and after painting:

How to Choose the Right Watercolor Paper

While stretching and proper drying of your painting can help keep it looking good and prevent curls, the biggest determinant of whether this issue happens is based on the type of watercolor paper you choose. And there are many sizes, qualities, and types of watercolor paper to go with. 

Pick High Quality Paper

First, make sure you go with high-quality watercolor paper. It may be tempting to save money and go with something that isn’t as thick. The really good watercolor paper is expensive. Some good options may be a little lower in quality but still strong enough for your watercolors. Save the expensive paper for your big works of art, and go with a watercolor paper closer to 140-pound stock. 

Consider How the Paper Was Produced

Production is also important. You can choose between machine-made, mold-made, and handmade. Only use machine-made if you absolutely have to. The other two are more durable and easier to use. They also have the right texture to make it nicer to paint on. Machine-made is cheaper, so it is tempting to purchase. But it is more prone to deterioration and distortion when you get it wet. 

Choose Watercolor Paper With Texture

That brings us to texture. Most watercolor paper will have a little bit of texture in it. The hot-press paper may be smooth, but this is also one of the worst options to choose to prevent curling and warping. There are varying degrees of texture, so try out a few and see which you like. More texture means the paper can handle more saturation, but many artists find that too much texture is hard to paint. 

As an artist, you will need to experiment a bit and see what works best for you. A good combination of inexpensive, quality, texture, and weight will help you get paper that you enjoy painting on while also not worrying about the paper curling. 

Final Words

Watercolor painting can be an enjoyable way to get some of your creativity and imagination on the canvas. But because of the high water content inside the paints, finding the right type of paper that won’t curl and warp when using it is important. Along with the right kind of paper, the steps we looked at throughout this article will help keep your paper strong and flat, no matter what you decide to create. 

Sources

• Wisegeek: What is Watercolor Paper?
• Hub Pages: How to Prevent Watercolor Paper from Curling
• Arteza: How to Choose the Right Watercolor Paper
• Dummies: Picking Watercolor Paper
• Amazon: PHOENIX Watercolor Paint Set of 12 Colors
• Amazon: ARTEXA 9X12” Expert Watercolor Pad
• Strathmore Artist: How to Flatten a Buckled Painting
• Watercolor Painting: Techniques for Using a Blow Dryer to Dry Paintings Quickly
• WikiHow: How to Stretch Watercolor Paper
• Art is Fun: Watercolor Paper