Watercolor painting is such a joy, but nothing frustrates me more than paper that buckles and warps during painting!
A smooth, flat surface is key for great results. In this article, I’ll share exactly how I stretch watercolor paper to avoid buckling, plus 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 we get into the stretching method, let me quickly show what buckling really is—and why it happens.
To demonstrate this, I take a regular sheet of watercolor paper. I don’t stretch it or do anything special. I just tape all four sides to my board.
Then, I wet only the center area of the paper, leaving the corners completely dry.
After about a minute or two, the paper starts to buckle. You can already see it lifting! The wet part expands, but the dry corners hold it back.
That’s when the paper fibers try to stretch sideways but get blocked. So they go up and down instead, creating little hills and dips.
When I remove the masking tape, I see these “mountains and valleys” more clearly. The wet paper can’t spread evenly because the edges stay dry. That’s why buckling happens!
Why Buckling Is a Problem When Painting
This step is so important to understand. If I try to paint on this buckled paper, I immediately get uneven washes.
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 light.
As a result, one part looks too dark, the other looks too pale. It ruins the smooth blend I want in a watercolor wash.
That’s why I always stretch my paper first!
What You Need to Stretch Watercolor Paper
Now, let me walk you through the materials I use. Most of these are easy to find in an art store.
Here’s my full list:
- Watercolor paper: I use Arches, 300 gsm, cold press, 100% cotton. It handles heavy washes so well!
- Wooden board: Mine is size A2, but you can pick A3 or A4 depending on your paper.
- Gum tape: This tape activates with water and sticks the paper down firmly.
- Masking tape: I use this for extra hold and 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 you know the tools, let’s go through the full stretching process step by step.
Step-by-Step: How I Stretch Watercolor Paper
This is the method I personally use—and it works well for me!
Step 1: Soak the Paper
First, I prepare the paper by ensuring the rough side faces up. That’s the side I like to paint on.
Then, I place it into a large bucket of clean water. I let it soak for about 10 minutes. This allows the fibers to absorb water and expand evenly.
While the paper is soaking, I move on to the next step.
Step 2: Prepare the Board and Tape
I get my wooden board ready. Then, I cut four strips of gum tape—one for each side of the paper.
Make sure you know which side of the tape is sticky! The sticky part is the one that feels dull, not shiny.
I also grab my masking tape and have it ready in case I want to secure the edges even more.
Step 3: Place the Paper and Smooth It Out
After 10 minutes, I lift the paper from the water and let the excess drip off. Then, I lay it flat on the board.
I use a clean towel and gently press from the center outward to remove any air bubbles trapped underneath. This part is super important! You don’t want bubbles to mess with your final painting.
Step 4: Apply Gum Tape on All Four Sides
Next, I grab my gum tape strips. Using a wet brush, I gently brush water over the sticky side, just once. If I go over it too many times, the adhesive will wash off. I’ve learned that the hard way!
Then, I carefully place each strip along one edge of the paper and press it down firmly.
Before I finish taping the last edge, I press the paper outward again to make sure it’s flat.
I even use the wooden end of my brush to push down the tape and seal it. It helps a lot!
Step 5: Add Masking Tape for Extra Hold
This step is optional, but I always do it. I add masking tape on the outer sides of the gum tape for extra security. I even tape the inner edges. It gives me a cleaner edge when I remove it later and keeps everything extra tight.
Then, I go over all the edges again with my brush to press everything down. Now, the paper feels secure and firm.
Step 6: Let It Dry Overnight
Once the paper is fully taped, I lay the board flat and leave it to dry overnight.
By the next day, the paper is usually dry and flat. But if it still has a tiny buckle or two, I use a hair dryer to speed up the drying. After that, it becomes perfectly flat!
Once dry, the stretching process is done, and I can start painting with no worries at all!
More Convenient Alternatives to Traditional Stretching
Now, I know this whole process might seem like a lot. So, let me show you two other options I use when I want something easier!
Option 1: Watercolor Block
This is a pre-glued block of watercolor paper. I have one from Arches—300 gsm, cold press, 100% cotton.
All four edges are already gummed down, so I don’t need to tape or stretch anything. I can just start painting right away!
Once I finish the painting, I take a plastic card (I use an old Starbucks card) and slide it under the top white edge to lift it up. Then, I just pull outward to separate the top sheet from the block.
It’s simple and convenient!
Option 2: Watercolor Board
This next one is a little rare, but I love it!
I got this Arches watercolor board at a workshop in Thailand. It comes with a thick, pre-mounted paper that’s already flat and secure. I don’t even need to stretch it.
During the workshop, I used tons of water and multiple layers. The paper stayed completely flat the whole time!
Even after drying, there’s no buckling at all. And the board is so thick, I could even frame the piece directly! I’m unsure where to find this exact board now, but if you spot it in a store, grab one!
Wrapping Up
Stretching watercolor paper makes a huge difference in your painting results. I love how it keeps the paper flat and helps my colors flow smoothly.
Trying the soaking and taping method or using watercolor blocks can save you from frustrating buckling. Ready to see how your paintings improve with perfectly stretched paper? Give it a go and enjoy the process!