Stretching Watercolour Paper

I watched in awe as my art teacher stretched my canvas for me. He explained as he went, and I listened as intently as my excited mind would allow. He pointed out how the two sides of the stretcher bars were different, and why. I nodded, thinking it was the most clever detail in the world. Then he pulled and stapled, pulled and stapled, pulled and stapled… “Now you add some water to the inside of the canvas” — my young highschool mind was blown. I loved watching the whole stretching process. When you start out with a floppy length of fabric and want to end up with a flat, stiff surface to paint on, the stretching step was obvious and impossible to miss.

But did you know you could (and imho, should) stretch watercolour paper too??

My face still lights up when I “reveal my secret” to friends. My heart races because this realization still makes me so happy. Stretching has pretty much overnight, changed watercolour painting from a frustrating, intimidating task to an enjoyable, fulfilling challenge.

Problems that Stretching Solves

  • Colours bleeding when you wanted solid, smooth edges

    Comparison of paint edges on unstretched vs stretched watercolour paper.
    Unwanted bleeding (a) that happens on unstretched paper vs a solid and smooth edge (b) on stretched paper.
  • The paper cockling when you use too much water

    Example of cockled paper from using too much water while painting.
    My poor fishies cockleeeeed. : ( I’ve left them under a huuge stack of books for weeks and could not make them any flatter.



  • Gator Foamboard (“gatorboard”)
  • Staple gun
  • Sponge + paper towels
  • Watercolour paper (acid free for longevity)


1. Place your desired paper on your board to ensure it fits. Or, in my case, I wanted to stretch a lot of papers at once, so I had to test out my arrangement.

Step 1: Test your watercolour paper arrangement on the board

Tip: Put a small ‘x’ in the corner of the paper on the side you want to paint on. You might lose track during the next step!

2. Soak the paper. Like, really, really soak it. This step will expand the fibres in your paper. This is the reason why stretched paper doesn’t cockle – you’re forcing the fibres to stay in this expanded state.

Depending on the dimensions of the paper, you can either slide the paper into a container of water, or in the bathtub. Make sure your container/bathtub is free of any grease/oil residue! Alternatively, you can soak the paper under running water.

Step 2: Soak your watercolour paper in water.

Let’s talk about SIZING for a moment.

Branch (2016) says that sizing is a coating added onto paper to change its absorbency. Without sizing, the paper will bleed uncontrollably (think: painting on newspaper), so watercolour paper needs some sizing. And YES, sizing CAN be washed off. So be careful not to soak/rinse your paper for too long.

Tip: Use cold water. Hot water removes more sizing than cold.

How do you know when your paper is adequately soaked? Test the corners. Gently bend (DON’T CREASE) the corner up and pay attention to its behaviour when you release it (Pelissier, 2013):

  • Corner ‘snaps’ back into original position: Not enough soaking
  • Corner maintains the position you bent it in: PERFECT! : ) Take it out!
  • Corner is limp, droops, just sadly hangs there: Too much soaking!

Tip: Be VERY careful not to crease your paper when it’s wet! This can cause the sizing to collect in a line, which will affect your painting.

3. Slide your paper out of the water and hold it by a corner to let excess water drop off. Lay the paper down on your board and gently smooth it out by patting it with a clean sponge from the center of the paper outwards. You want the paper to end up looking completely flat.


4. Start stapling! Always work on opposite sides. That is, if you first stapled the left side, do the right side next. Then the bottom, followed by the top, etc.

Start by stapling the center of the sides, then work your way towards the corners. Leave about an inch between staples.

I staple about 5 mm – 1 cm in from the edges of the paper. You can do 1 inch if you like!


5. Let it dry overnight, then it’s ready to be used!

6. Paint your latest masterpiece. When you’re done and all’s dry, you can remove the paper by gently prying it off with a butter knife (or something similar)


Alternative Methods

At the moment I prefer the stapling method because I already had all the materials I needed laying around the house, and I also like that the margins could be thinner. : ) Here are some other methods:

Butcher’s Tape / Gummed Paper Tape Method:

Discusses all four methods (wooden stretcher, wheat paste):

If you don’t want to deal with stretching at all:

  • Buy thicker paper. 200 lbs should work (I haven’t tested it yet), but 300 lbs would be best, or
  • Use watercolour blocks. Each sheet of paper in the pad is glued down on all four sides, which helps the painting dry flat. Also great for painting en plein air.

What is your preferred stretching method?

That’s all for now! Let me know if you have any questions!


Bonus: Check out how much larger stretched watercolour paper is!

Size comparison of stretched vs not stretched watercolour paper.
That’s about a 5 mm difference. Cray!







How to stretch watercolour paper to prevent it from cockling.

14 thoughts on “Stretching Watercolour Paper

  1. I had no idea!!!! This is awesome. Something I will remember when I can find the time to paint. I love to do artwork, but sadly, my home has taken me on a different path. I always have a project or two to do. This post is wonderful and I’m super impressed with your talents. Looking forward to be inspired more by you! Happy New Year. All the best, Koko :)

    Liked by 2 people

      1. Yes, mostly home improvement. And lots of yard-type work, (I’ve got two acres of work!) it all keeps me busy. I would really rather be doing art-type projects. :) Is like to do watercolor art. I need more time in my day! Hahaha.

        Liked by 1 person

        1. Wow, what are you planning to do with your two acres? Hobby farm? : ) : )

          I think watercolour would suit your busy lifestyle! It’s wonderful because you can just walk away at any moment. I love that you can revitalize your palette by just adding water! Unlike acrylics – when it’s dry, it’s trash.

          Liked by 1 person

  2. I had NO idea that you could do this with paper?!? Oh my goodness– how informative!! Love it! I seriously need to sit down and do these watercolors sometime. I love painting, but haven’t done it in a long time. I am craving some artistic expression like this!

    Liked by 3 people

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