Watercolor painting, with its vibrant pigments and fluid techniques, relies heavily on the absorbent qualities of specialized paper. However, a persistent challenge for watercolor artists is the inevitable curling or warping of their paper due to the interaction with moisture.
This undesirable outcome can mar the intended artwork and disrupt the creative process. To preserve the integrity of your watercolor paintings, it is crucial to employ effective strategies for preventing paper curling.
In this guide, we will explore proven methods and techniques to keep watercolor paper flat and stable during the painting process. These practices range from stretching the paper to selecting the right materials and creating an optimal painting environment.
By implementing these strategies, you can unlock your full artistic potential without the frustration of paper curling.

Why Does Watercolor Paper Curl?
Watercolor paper curls primarily due to its interaction with moisture, which is inherent to the watercolor painting process.
Several factors contribute to why watercolor paper curls:
Absorption of Water
Watercolor paper is designed to absorb water and pigments from paints. When you apply water or paint to the paper, it absorbs the moisture. This absorption causes the paper fibers to expand.
Expansion and Contraction
As watercolor paper absorbs moisture, it swells and expands. Conversely, as it dries, it contracts. This natural expansion and contraction can cause the paper to curl or warp if it’s not properly stabilized during the drying process.
Fiber Structure
Watercolor paper is constructed with a specific fiber structure that allows it to hold water effectively. However, this structure can also make it more susceptible to distortion when exposed to moisture.
Moisture Differential
When you apply water or paint to one side of the paper, it creates a moisture differential between the painted side and the unpainted side. This difference in moisture content can lead to uneven expansion and curling as one side dries faster or slower than the other.
Environmental Factors
The environment in which you work and store your watercolor paper can impact its tendency to curl. High humidity can cause the paper to absorb excess moisture from the air, leading to curling.
Conversely, low humidity can cause the paper to dry too quickly, resulting in warping.
Paper Weight
Lighter-weight watercolor paper is more susceptible to curling than heavier-weight paper. Heavier paper provides more stability and resists curling better due to its thickness and greater absorbency.
How to Keep Watercolor Paper From Curling?

Watercolor paper has a natural tendency to curl when it comes into contact with moisture, such as watercolor paint. This can be frustrating for artists, as it affects the stability and appearance of their artwork.
Here are some ways to prevent watercolor paper from curling:
Stretching the Paper
Stretching watercolor paper involves soaking it in a clean tub or basin of water for 5-15 minutes until it’s fully saturated.
After removing the wet paper and letting excess water drip off, you securely attach it to a flat, rigid surface, like a masonite board or gator board, using masking tape, staples, or gummed paper tape.
The paper should be stretched taut and free of wrinkles. As the stretched paper air-dries completely, the fibers tighten within the paper, preventing any buckling or curling during the painting process.
Use Watercolor Blocks
Watercolor blocks offer a convenient solution to paper curling. These pads feature pre-stretched paper sheets glued on all sides, except for a small opening.
When you’re ready to paint, simply peel off the top sheet, and the paper is already stretched and secured within the block. Once your painting is dry, cut it from the block using an X-Acto knife, revealing the next sheet for your artwork.
Choose Heavier Paper
Selecting watercolor paper with a weight of 300 lb (638 gsm) or higher is an effective way to minimize curling. Heavier paper is thicker and more absorbent, providing greater stability and resistance to warping when exposed to watercolor paint.
Proper Storage and Environment
Maintaining a controlled environment is vital. Store your watercolor paper in a dry, cool area, away from direct sunlight and high humidity. Ensure the paper remains flat and shielded from environmental moisture, which can lead to curling.
Paper Fanning
Before commencing your painting session, gently fan the sheets in your watercolor paper pad or block. This action reduces static between the sheets and enhances air circulation, mitigating humidity-related issues and potential paper curling.
Tape Down the Edges
When working with loose sheets of watercolor paper, secure the edges to a drawing board or watercolor block using masking tape or artist’s tape. This step ensures the paper remains firmly in place during the painting process, reducing the risk of curling.
Mindful Painting Techniques
Implementing proper painting techniques is crucial. Apply washes and layers evenly across the paper to maintain uniform moisture distribution. Avoid using excessive water or paint, which can lead to uneven absorption and, subsequently, curling.
Use Watercolor Grounds or Sizing
Enhance your paper’s performance by preparing its surface with watercolor grounds or sizing. This pre-treatment can improve paint adhesion and reduce the likelihood of curling during your artwork’s creation.
Avoid Overworking Wet Areas
Exercise caution when working wet-in-wet, as excess moisture can contribute to paper warping. Blot or lift any excess water or paint when necessary to maintain control over the paper’s flatness.
Dry the Paper Flat
Once your artwork is complete, place the paper between clean sheets of blotting paper or wax paper and gently flatten it under a stack of heavy books.
This helps preserve its flatness as it dries. Properly drying the paper is essential to ensure it remains free of curling in the final result.
What is the Most Effective Method to Prevent Watercolor Paper From Curling?

The most effective method to prevent watercolor paper from curling is to stretch it before you start your painting. Stretching watercolor paper involves saturating the paper with water and then securing it to a flat, rigid surface until it dries.
This process ensures that the paper remains flat and stable during your painting, minimizing the chances of curling or warping.
Here’s a step-by-step guide on how to stretch watercolor paper:
Gather Your Materials
Before you begin, gather the necessary materials: your watercolor paper (preferably in a loose sheet or pad form), a clean tub or basin large enough to accommodate your paper, clean water, a flat and rigid surface (like a masonite board or gator board), and either masking tape, staples, or gummed paper tape.
Soak the Paper
Start by submerging the watercolor paper in the clean tub or basin of water. Allow it to soak for 5 to 15 minutes or until it’s completely saturated.
You can also use a sponge or a large brush to ensure even wetting of the paper’s surface.
Remove Excess Water
Carefully lift the wet paper out of the water, letting any excess water drip off. Be gentle during this process to avoid tearing the paper, as it will be fragile when wet.
Secure the Paper
Lay the soaked paper flat on your chosen flat and rigid surface. Use masking tape, staples, or gummed paper tape to secure the paper to the board. It’s crucial to ensure that the paper is stretched taut and free of wrinkles during this step.
You can choose to tape down all four edges or just the top and bottom if you want to work with the sides of the paper.
Allow It to Dry
Leave the stretched paper to air-dry completely. As the paper dries, the paper fibers within it will tighten, preventing any buckling or curling during the painting process.
It’s essential to let it dry naturally, as applying heat or forceful drying can negate the stretching process.
FAQs
Are there specific paper weights that resist curling better?
Heavier watercolor paper with a weight of 300 lb (638 gsm) or higher is less prone to curling due to its thickness and absorbency.
Can I prevent paper curling by using watercolor blocks?
Yes, watercolor blocks come pre-stretched and glued on all sides, offering a convenient solution to paper curling.
What should I consider when storing watercolor paper to prevent curling?
Store your paper in a dry, cool area away from direct sunlight and high humidity to prevent moisture-related curling.
What painting techniques can help prevent paper curling?
Apply washes and layers evenly, avoiding excessive moisture and paint to maintain uniform absorption and minimize curling.
Can I prevent watercolor paper from curling by using a hairdryer or heat gun to speed up the drying process?
It’s not recommended to use heat to dry watercolor paper as it can lead to uneven drying, which may exacerbate curling and warping issues.
To Recap
In the world of watercolor artistry, the battle against paper curling is a common yet conquerable challenge. As we conclude this guide, it becomes evident that preserving the pristine flatness of your watercolor paper is not an elusive feat.
By embracing techniques such as stretching, selecting heavier paper, and maintaining an ideal painting environment, you can effectively ward off the unsightly effects of moisture-induced curling.
With diligence and practice, you will find your creative process enriched and your artwork enhanced. Remember, the journey of mastering watercolor is not just about the strokes and colors; it’s also about understanding and taming the very canvas on which your imagination comes to life.
Armed with these strategies, your watercolor creations are poised to flourish, unburdened by the vexation of paper curling.
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