How to Flatten a Watercolor Painting: Tips and Tricks for a Smooth Finish

When learning how to flatten a watercolor painting you need to take a few steps to ensure that it dries evenly and doesn’t curl or buckle. If you’ve ever painted with watercolors, you know that the paper can easily become warped when it gets wet. This can be frustrating when you’re trying to create a flat, smooth painting.
But don’t worry, flattening a watercolor painting is a straightforward process that you can do at home with a few basic materials. One of the most common methods for flattening a watercolor painting is to use weights.
You’ll need to place the painting between two pieces of clean paper or towels, and then stack books or other heavy objects on top. This will help to distribute the weight evenly and press the painting flat. Another method involves using moisture and weights.
You’ll need to mist the underside of the painting, place it image-down on a sketch or copy paper, and then add another sheet of paper or a clean towel on top. Finally, you can use an iron to flatten your watercolor painting.
This method involves wetting the paper with a brush or sponge, placing a towel or paper on top, and then ironing the painting on a low or medium heat setting.
Different Methods for Flattening a Watercolor Painting
Flattening a watercolor painting is an essential step in the process of displaying or framing your artwork. There are different methods for flattening a watercolor painting, and you can choose the one that suits your needs best.
In this section, we will discuss the most common methods used for flattening a watercolor painting.
The Most Common Method
The most common method used for flattening a watercolor painting is the moisture and pressure method. This method involves using a damp sponge or blotting paper to moisten the surface of the paper.
The paper fibers will absorb the moisture and expand, causing the paper to buckle or curl. The next step is to place the painting face down on a flat surface and cover it with a clean blotting paper or towel.
You can place a heavy object on top of the towel to apply pressure to the painting. Leave the painting under pressure for at least 24 hours, and it should be flat when you remove the weight.
The Iron Method
The iron method is another popular method for flattening a watercolor painting. This method involves using an iron to apply heat and pressure to the painting.
To use this method, you need to place the painting face down on a flat surface and cover it with a clean blotting paper or towel.
Set the iron to a low heat setting and apply it to the towel, moving it in circular motions. Be careful not to apply too much pressure or heat, as this can damage the painting.
Leave the painting under pressure for at least 24 hours, and it should be flat when you remove the weight.
The Paper Press
The paper press method is a more advanced method for flattening a watercolor painting. This method involves using a paper press to apply pressure to the painting.
A paper press is a device that applies pressure evenly to the painting, ensuring that it dries flat. To use this method, you need to place the painting face down on a flat surface and cover it with a clean blotting paper or towel.
I have been lucky in that my father was a bookbinder and over the years we have collected lots of equipment that I have repurposed for art. One of these is a paper press. Mine is probably the heaviest and oldest thing I own.

Place the painting in the paper press and apply pressure. Leave the painting under pressure for at least 24 hours, and it should be flat when you remove the weight.
It is important to note that these methods work best for mild cases of buckling or curling. If your painting has a lot of water or too much water has been used in wet techniques or washes of transparent watercolor, these methods may not be effective.
If you have used thick applications of watercolor paint, the surface of the paper may be damaged, and the stretching process may be necessary to flatten the painting.
The best method for flattening a watercolor painting depends on the severity of the buckling or curling and the surface of the paper. Choose the right method to avoid damaging your artwork.
Preparing Your Painting for Flattening
If you have a watercolor painting that has become warped or buckled, it can be frustrating to try and display it. Lucky for us flattening a watercolor painting is a straightforward process that you can easily do at home.
But before you begin, make sure you have a clean, flat surface to work on and the following materials:
- Painter’s tape or masking tape
- Heavy books or a heavy object
- Paper press or something similar
- Gummed tape (optional)
Cleaning the Surface
The first step in preparing your painting for flattening is to ensure that the surface is clean. Use a soft-bristled brush or a clean, lint-free cloth to gently remove any dust or debris from the surface of the painting. This will ensure that the painting is not damaged during the flattening process.
Taping the Edges
Once the surface is clean, use painter’s tape or masking tape to secure the edges of the painting to a clean, flat surface.
This will help to prevent the painting from shifting or moving during the flattening process. Make sure to apply the tape gently and avoid pressing too hard, as this can damage the delicate surface of the painting.
Adding Weight
Next, you will need to add weight to the painting to help flatten it. You can use heavy books, a heavy object, or a paper press for this step.
Place the weight on top of the painting, making sure that it is evenly distributed across the surface. If you are using a paper press like a bookbinder’s paper press below, follow the manufacturer’s instructions for use.
If you are using heavy books or a heavy object, you may want to place a piece of gummed tape on the top of the stack to help hold everything in place.
This will help to prevent the books or object from shifting and potentially damaging the painting.
Leave the painting under the weight for at least 24 hours. Once the painting is flat, remove the weight and carefully remove the tape from the edges of the painting.
Your watercolor painting should now be flat and ready to display!
Flattening Techniques for Different Types of Paper
If you’re looking to flatten a watercolor painting, the technique you use will depend on the type of paper you used. Here are some techniques for different types of paper:
Watercolor Blocks
If you used a watercolor block, you don’t need to worry about stretching or flattening the paper. The paper is already stretched and glued to a backing board, which keeps it flat.
Simply remove the painting from the block and you’re good to go.
Watercolor Sheets
If you used individual watercolor sheets, you’ll need to stretch the paper before you start painting to prevent it from buckling.
Once you’ve finished your painting, you can use the following technique to flatten the paper:
- Place the painting face down on a clean, flat surface
- Lightly mist the back of the paper with clean water
- Cover the painting with a clean towel or piece of paper
- Iron the towel or paper on a low setting
Thinner Papers
If you used a thinner watercolor paper, you’ll need to be careful when flattening it to avoid damaging the paper.
Here’s a technique you can use:
- Place the painting face down on a clean, flat surface
- Lightly mist the back of the paper with clean water
- Cover the painting with a clean towel or piece of paper
- Place a heavy book or other weight on top of the towel or paper
- Leave the painting to dry for 24 hours
Heavier Papers
If you used a heavier watercolor paper, you may need to use a combination of stretching and flattening techniques to get the best results.
Here’s a technique you can use:
- Stretch the paper before you start painting
- Once you’ve finished your painting, mist the back of the paper with clean water
- Cover the painting with a clean towel or piece of paper
- Iron the towel or paper on a low setting
Unstretched Paper
If you used unstretched watercolor paper, you’ll need to stretch it before you start painting to prevent it from buckling. Once you’ve finished your painting, you can use the following technique to flatten the paper:
- Place the painting face down on a clean, flat surface
- Lightly mist the back of the paper with clean water
- Cover the painting with a clean towel or piece of paper
- Iron the towel or paper on a low setting
Tips and Tricks for Flattening a Watercolor Painting
When you first start learning how to flatten a watercolor painting, you may find that flattening watercolor paintings can be a daunting task. But with the right techniques, you can learn to do this quickly with great results.
Here are some tips and tricks to help you flatten your watercolor painting:
Using a Spray Bottle
This is probably the most easiest method you will learn when learning how to flatten a watercolor painting. This involves flattening a watercolor painting by using a spray bottle and some heavy books.
First, find a clean flat surface and put your painting face-down.
Then, spritz the back of the painting with a spray bottle so it’s evenly wet. Use a brush or sponge to spread out the water if needed.
Finally, lay down something flat, like a board, that is larger than the size of the painting, and put something heavy on top, like books or a box. Leave it for 24 hours.
Using a Damp Sponge
If you don’t have a spray bottle, you can use a damp sponge to flatten your watercolor painting. First, wet the sponge and wring out the excess water.
After you place the painting face-down on a clean flat surface and lightly dampen the back of the painting with the sponge.
Place a piece of paper on top of the painting and press it down with a heavy object, like a book or a board. Leave it for a few hours or overnight.
Using a Paper Press
If you’re looking for a quicker method, you can use a paper press. First, find a clean flat surface and put your painting face-down.
Then place a piece of cardboard on top of the painting and put it in a paper press.
Leave it for a few hours or overnight. If you don’t have a paper press, you can use a stack of heavy books instead.
Using a Surface with Low Humidity
If you live in a humid area, depending on the humidity level it can be difficult to flatten your watercolor painting.
In this case try using a surface with low humidity, like a wood table. Place your painting face-down on the table and cover it with a clean sheet of paper.
Iron the back of the paper with a burst of steam, being careful not to touch the actual painting.
This will help to flatten the painting quickly, but be sure to use a low heat setting and keep the iron moving to avoid damaging the painting.
These are some of the best things you can do to flatten a watercolor painting quickly and with great results.
Many artists have their favorite watercolor tricks but these are some of the best advice you can follow. The worst thing you can do is rush the process, so take your time and follow these tips for the best results.
how to flatten a watercolor painting – Wrap up!
Now that you’ve learned how to flatten a watercolor painting, you can save yourself from the frustration of dealing with curled or distorted artwork. Remember that prevention is key, so make sure to store your paintings properly and avoid exposing them to extreme temperatures or humidity.
Next time you need to flatten a painting, you can choose from various methods, such as the moistening and pressing method, the use of weights, or the use of a flatbed scanner.
It’s important to be patient and take your time when flattening a watercolor painting. Rushing the process can result in damage to your artwork. Allow 24-72 hours for the painting to dry completely before removing any weights or coverings.
Remember, as a visual artist, it’s important to take care of your artwork and ensure that it looks its best. By following these simple steps, you can maintain the quality of your watercolor paintings and enjoy them for years to come.
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Joseph Colella is a frustrated artist with over 40 years experience making art (who moonlights as a certified Business Analyst with over 20 years of experience in tech). While he holds a Diploma in Information Technology, in true wasted talent style he spent years trying to get into various Art degrees from the Accademia di Belle Arti (Napoli), and failed to get into the Bachelor of Arts (Fine Arts) at the University of Western Sydney. His goal is to attend the Julian Ashton School of Art at The Rocks Sydney when he retires from full time work. In his spare time, he writes for the this blog, WastedTalentInc, where he shares practical advice on art, making art, and art materials. Joseph’s art has been sold to collectors all over the world from the USA, Europe and Australasia. He is a trusted source for reliable art and copyright/fair use advice and is committed to helping his readers make informed decisions about making them a better artist.
He also loves all things watches (ok it’s an addiction) so show him some love and visit his other website https://expertdivewatch.com