Every watercolor painter has experienced the dreaded buckle. What started as a beautiful flat sheet of watercolor paper has turned into a rippled surface during the painting process.
Buckling, otherwise known as warping, is caused by cotton fibers of the watercolor paper stretching when the paper becomes wet. The stretching can occur unevenly, creating hills and valleys in your paper. Applying the paint smoothly is challenging on this rippled surface.
The best way to prevent buckling is to stretch the watercolor paper beforehand. The process includes saturating the paper until it has fully expanded and then suspending it in its stretched state while it dries.
There are many different methods of stretching watercolor paper, some more involved than others.
This method is simple and effective.
What you’ll need
- Watercolor paper
- Gatorboard* that is slightly larger than your piece of watercolor paper.
- Office stapler and staples
- Spray bottle
- Clean, soft towel
- Gatorboard is like foam core but much more sturdy. Ideally, the gatorboard should be 1/2″ thick to allow depth for staples, but I use 3/16″ gatorboard for smaller paintings with no problem. On the thinner board, the staples will poke out a bit at the back. I’ll share my solution for that.
Step 1: Make sure the gator board is clean.
Wipe the board with a damp towel to remove any watercolor or gouache paint. My board doesn’t look clean but all the paint on here is dried acrylic paint so it won’t transfer onto the paper.
Step 2: Spray the back of your paper.
Determine the front and back of your paper. I mark the back with a B in the corner. Lay the watercolor paper front side down and thoroughly spray the back with water from a spray bottle. I use a trigger-style spray bottle.
Look at the paper from an angle to make sure you have plenty of water on the surface of the paper.
Set a timer for four minutes.
After four minutes, tilt the gatorboard and let the excess water drain into a bowl or a dish.
Step 3: Spray the front of the paper
Lift the paper at the edge and turn it over so that the front side, which is dry, is facing up. Using the spray bottle, thoroughly spray the front side.
Set a timer for four minutes.
If the paper is not laying completely flat at this point, lift the edge of the paper and lay it back down. If there is still a problem with it not laying flat, spray the problem area with water.
After four minutes, tilt the board to drain off the excess water.
Step 4: Gently remove excess water with a towel.
Lay a clean soft towel over the paper. Lightly press on the top of the towel to remove excess water. You can also use soft paper towels, such as Viva. You can let the paper towels dry and reuse them. Avoid paper towels that are heavily textured with a pattern.
IMPORTANT: The paper is very soft at this point. Use a light touch to prevent indentions or scratches.
Step 5: Staple
Open a standard office stapler* into the tacking position. Apply staples to the edge of the paper leaving about 1/2″ gap between staples. If you’re using 3/16″ thick gatorboard, lay the board on a piece of cardboard or foamcore to prevent the tips of the staples from damaging your table.
- A standard office stapler works well with the gatorboard. A heavier staple gun with larger staples could break the board. An office stapler is so much easier to work with plus the staples are easy to remove!
Leave the paper to dry flat overnight.
Your watercolor paper is now stretched and flat!
If you get one area of the paper really wet while you are painting, you may notice a little additional stretching, but the stretching should be minimal and the paper will dry flat.
Once your painting is complete, you can use a staple remover or a small flat screwdriver to lift the staples.
Vinita Pappas 2021