Mastering Paper Paintings: Flattening And Stiffening Techniques

Watercolour paper is prone to warping, and this can be frustrating for artists who want to display their work. Luckily, there are several methods to flatten a painting on paper. Most methods involve dampening the back of the paper, placing it between two sheets of absorbent paper, and then weighting it down with a flat object. The paper will dry flat if left for long enough. However, artists must be careful not to use too much water, especially if the painting was created with water-soluble media.

Mist the back of the paper with water

Misting the back of a painting with water is a common method used to flatten and stiffen fine paintings on paper. This method is especially useful for watercolour paintings.

Firstly, it is important to ensure that only water is in the mister. Residual chemicals from other liquids can damage the painting. It is also important to use distilled water, as tap water contains minerals that can make the paper crusty and hard. The mister should be held at least one foot away from the paper and the water should be sprayed lightly to dampen the paper. The paper should not be dripping wet.

Once the paper is lightly damp, it should be placed on a clean, smooth, and untextured surface. A sheet of sketch paper or plain newsprint should be placed on this surface, and the painting should be placed image-side down on the paper. The painting should then be covered with another sheet of paper or a towel.

At this point, a weight can be placed on top of the painting to flatten it. A heavy, flat object, such as a brick or a stack of books, can be used. If using an iron, it should be set to medium-low heat and gently rubbed over the surface. The heat can be adjusted as needed to allow the dampness to relax the paper fibres.

Place the painting image-side down

To flatten and stiffen a fine painting on paper, one of the recommended methods involves placing the painting image-side down. This method requires the following materials: two sheets of clean white paper, a spray bottle with water, a rigid flat object, and a heavy item. The white paper should be larger than the painting, and the rigid flat object should be larger than the painting as well.

To start, lay the first sheet of white paper on a clean surface. Then, place the painting image-side down on the white paper. Be sure to only use water in your spray bottle, as residual chemicals can affect your artwork. Set your water bottle to the finest mist and spray the back of the painting lightly. Do not over-wet the paper. If you used water-soluble paint, be cautious with the amount of water sprayed on the back, as it may dissolve the paint on the front side.

After misting the back of the painting, cover it with the second sheet of white paper. Then, place the rigid flat object on top, followed by the heavy item(s). Leave the setup for an hour or more, depending on how saturated the paper is. If the paper is still damp, reassemble the stack and let it sit longer. If there are still major warps, try the process again, as you may not have used enough water.

Once the paper is dry, remove the weights and rigid flat object. If the paper still has wrinkles or feels damp, replace the top sheet of white paper with a fresh, dry one. Repeat this process until the paper is smooth and dry. Finally, leave the painting undisturbed for 24 to 72 hours to ensure complete dryness.

Cover with a sheet of paper or towel

To flatten and stiffen a fine painting on paper, you can try the following approach:

Firstly, get the back of the painting damp. You can do this by misting the back of the paper with water using a fine mist—you can also use a damp sponge, but be careful not to over-wet the paper. Then, place the painting image-side down on a sheet of sketch paper, newsprint, or plain paper that is larger than the painting. Cover the painting with another sheet of sketch paper or a towel.

Next, place a board, rigid flat object, or iron on top of the painting sandwich. The board should be larger than the paper. You can then place weights on top of the board—books can be used if weights are unavailable. Leave the board and weight in place for 2 hours, then remove and replace the damp sketch paper with a fresh, dry sheet. Repeat this process until the paper is no longer wrinkled or damp, which typically takes around 4-6 cycles. Finally, put another new dry sheet of paper down and cover it with the board and weight, leaving it for 24-72 hours until the paper is completely dry.

This approach uses dampness and weight to flatten the painting, allowing the paper fibres to relax and straighten out. It is important to note that if water-soluble paint was used, extra care must be taken to avoid getting the front of the painting wet, as this could cause the paint to dissolve.

Place a flat, rigid object on top

To flatten and stiffen a fine painting on paper, one of the methods you can use involves placing a flat, rigid object on top. This method is effective in flattening the paper and removing any warps, leaving at most a slight bend that can be easily corrected by framing or mounting the painting.

• Prepare a clean, smooth, and flat surface to work on. A wooden table or a piece of plywood can be used as the base.
• Lay a sheet of white paper, such as drawing paper or parchment paper, on the prepared surface. The paper should be larger than your painting.
• Place your painting on top of the white paper, with the painted side facing down.
• Lightly mist the back of your painting with water using a fine mist setting on a water bottle. For a small piece, two to three sprays are usually sufficient. Be careful not to over-wet the paper, especially if you have used water-soluble paint.
• Lay another sheet of white paper on top of the painting.
• Cover the painting with a flat, rigid object. The object should be larger than your painting. Examples of suitable rigid objects include a scrap of laminate flooring, MDF shelf, hardboard from an old paper pad, or a cutting board.
• Place a heavy object on top of the flat, rigid object. You can use weights, a bucket of paint, a stack of books, or a brick.
• Wait for an hour or more, depending on how saturated the paper is. If the paper is still damp, reassemble the stack and let it sit longer. You may need to repeat the process if you didn't use enough water initially.
• Remove the rigid object and heavy item, and replace the top sheet of white paper with a fresh, dry one.
• Place the rigid object and heavy item back on top and leave it for 24-72 hours until the paper is completely dry.

By following these steps and using a flat, rigid object, you can effectively flatten and stiffen your fine painting on paper.

Put weights on top

To flatten and stiffen a fine painting on paper, one method is to use weights. This method does not require any heat and is less likely to damage the painting.

First, lay the painting on a clean, smooth, and untextured surface, image-side down. Place two sheets of clean white paper, such as drawing paper or parchment paper, that are larger than your painting on top. Then, cover the painting with a rigid, flat object that is also larger than the painting, such as a scrap of smooth shelving or a cutting board. Finally, place weights on top. You can use books as weights if actual weights are unavailable.

Leave the weights on for 24 to 72 hours until the paper is completely dry. It is recommended to remove the weights and the top sheet of paper every 2 hours and replace the damp sheet with a dry one. Repeat this process until the paper is no longer wrinkled or damp, which usually takes around 4 to 6 cycles.

If the painting is still warped, you can repeat the entire process. You can also try the process again if you suspect that you did not use enough water.

This method has been found to be successful in removing warps, leaving only a slight bend that is usually flattened when the painting is framed or mounted on another substrate like wood.

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