Watercolor painting is such a joy, but nothing frustrates Kerrilyn Cheah more than paper that buckles and warps while she’s working!
A smooth, flat surface is essential for getting clean washes and beautiful results.
In this article, Kerrilyn Cheah shares exactly how she stretches watercolor paper to avoid buckling, along with some easy alternatives if you don’t want to deal with all the materials.
Let’s dive right in!
Contents
What Causes Watercolor Paper to Buckle?
Before getting into the stretching method, the artist first explains what buckling really is—and why it happens.
To demonstrate this, the artist takes a regular sheet of watercolor paper. The paper is not stretched or prepared in any special way. All four sides are simply taped to a board.
Then, only the center area of the paper is wetted, leaving the corners completely dry.
After about a minute or two, the paper starts to buckle. The surface already begins lifting. The wet part expands, but the dry corners hold it back.
At this point, the paper fibers try to stretch sideways but are blocked. So they move up and down instead, creating little hills and dips.
When the masking tape is removed, these “mountains and valleys” become even more visible. The wet paper cannot spread evenly because the edges remain dry. That is why buckling happens.
Why Buckling Is a Problem When Painting
This step is important to understand. If painting continues on this buckled paper, uneven washes appear immediately.
Here’s what happens: water gathers in the dips (the valleys), creating puddles. These puddles hold more pigment, while the raised parts dry faster and stay lighter.
As a result, one area looks too dark while another appears too pale. This destroys the smooth blend desired in a watercolor wash.
For this reason, the artist always stretches the paper first.
What the Artist Will Need to Stretch Watercolor Paper
Next, the artist introduces the materials used. Most of these supplies are easy to find in an art store.
Here’s the full list:
- Watercolor paper: Arches, 300 gsm, cold press, 100% cotton. It handles heavy washes very well.
- Wooden board: The artist uses size A2, but A3 or A4 can be chosen depending on the paper.
- Gum tape: This tape activates with water and sticks the paper down firmly.
- Masking tape: Used for extra hold and for creating a neat border.
- Towel or cloth: For pressing down and drying surface water.
- Brush: To wet the gum tape gently.
- Bucket: Big enough to fully soak your paper.
- Pen knife: For removing the tape when it’s all dry.
Now that the tools are introduced, the artist walks through the full stretching process step by step.
Step-by-Step: How the Artist Stretches Watercolor Paper
This is the method the artist personally uses—and it works reliably.
Step 1: Soak the Paper
First, the paper is prepared with the rough side facing up—the surface preferred for painting.
Then, the sheet is placed into a large bucket of clean water and left to soak for about 10 minutes. This allows the fibers to absorb water and expand evenly.
While the paper is soaking, the artist moves on to the next step.
Step 2: Prepare the Board and Tape
The artist prepares the wooden board and cuts four strips of gum tape—one for each side of the paper.
It is important to identify which side of the tape is sticky. The sticky side is the one that feels dull, not shiny.
Masking tape is also prepared in case the edges need additional securing.
Step 3: Place the Paper and Smooth It Out
After 10 minutes, the soaked paper is lifted from the water and the excess is allowed to drip off. The sheet is then laid flat on the board.
A clean towel is used to gently press from the center outward to remove any trapped air bubbles. This step is essential, as bubbles can interfere with the final painting.
Step 4: Apply Gum Tape on All Four Sides
Next, the prepared gum tape strips are used. With a wet brush, the artist gently brushes water over the sticky side once. Brushing too many times removes the adhesive.
Each strip is placed along one edge of the paper and firmly pressed down.
Before finishing the last edge, the artist presses the paper outward once more to ensure it is flat.
The wooden end of a brush is used to push down the tape and seal it securely.
Step 5: Add Masking Tape for Extra Hold
This step is optional, but the artist always includes it. Masking tape is added along the outer sides of the gum tape for extra support. The inner edges are taped as well. This not only strengthens the hold but also creates a cleaner edge when removed later.
All edges are pressed down again with a brush. At this stage, the paper feels secure and firm.
Step 6: Let It Dry Overnight
Once fully taped, the board is laid flat and left to dry overnight.
By the next day, the paper is usually dry and flat. If a slight buckle remains, a hair dryer can be used to finish the drying. After that, the sheet becomes perfectly flat.
Once dry, the stretching process is complete and ready for painting.
More Convenient Alternatives to Traditional Stretching
Since the full stretching process can feel time-consuming, here are two easier alternatives the artist often uses.
Option 1: Watercolor Block
A watercolor block is a pre-glued stack of watercolor paper. The artist uses one from Arches—300 gsm, cold press, 100% cotton.
All four edges are already gummed, so no taping or stretching is required. Painting can begin immediately.
When the painting is finished, a plastic card (such as an old membership card) is slid under the top white edge to
It’s simple and convenient!
Option 2: Watercolor Board
This option is less common but extremely effective.
The artist obtained this Arches watercolor board during a workshop in Thailand. It contains thick, pre-mounted watercolor paper that stays perfectly flat, even with heavy water use and multiple layers.
Throughout the workshop, the sheet never buckled, even after drying. The board is so sturdy that the artwork can be framed directly.
Wrapping Up
Stretching watercolor paper greatly improves painting results. It keeps the surface flat, helps colors flow smoothly, and prevents unwanted puddles and patchy washes.
Whether using the soaking-and-taping method, a watercolor block, or a watercolor board, these approaches eliminate frustrating buckling and create a smoother painting experience.
Ready to enjoy perfectly flat watercolor paper? Give the method that suits you best a try and enjoy the creative process!