Soaking and Stretching Watercolour Paper

Nothing is more frustrating for a watercolour artist than to lay down a fresh wash of paint, only to have your paper buckle and warp underneath it. Fortunately, there are a few ways to make sure your paper stays flat when working with it.  

  • Using a HEAVY WEIGHT paper e.g. 425gsm (200lb) and above will be stable when you add water.
  • Using a BLOCK with four glued edges. The paper is surrounded by a glued edge, so the paper dries flat.
  • SOAKING and STRETCHING the paper

What are the benefits of soaking and stretching watercolour paper?

When your paper doesn’t dry flat, the overall look of a piece can look unprofessional and ruin the final image. When painting with paper that is cockled (buckled), pools of water can form where the paper bends, leaving uneven washes and difficulty controlling the paint. Stretching your paper means you can use as much water and as many layers as you want.

Equipment for soaking and stretching watercolour paper:

  • Your watercolour paper
  • Flat wooden board (marine ply is recommended)
  • Clean tub big enough to submerge the paper in water
  • Gummed tape
  • Clean sponge (only used for art, and not been in contact with detergents).

How to stretch watercolour paper

1. Fill up your tub of choice with water, making sure it is full enough to completely submerge the paper. If using a bathtub, please make sure that the tub is clean before use, as leftover residue in soap/shower gel can actually damage the paper.

2. Take your paper and submerge it in the water for approx. 3 minutes for 190gsm (90lb) paper, or approx. 8 minutes for 300gsm (140lb) paper. Many artists may recommend differently as different timings will work for different people, so experiment and see what works for you.

3. Once the paper has been submerged, take it out, and lay it flat on your wooden board.

4. Tilt the board and let the excess water run off the board. Take care not to touch the area you wish to paint, as this can leave marks on your painting.

5. Tear or cut your gum tape into four pieces, two lengths and two widths of your paper. You may want to do this before you begin.

6. Working quickly, gently wet the gum tape with your sponge, being careful to only wet the sticky side. The glue is water activated which makes it perfect for stretching paper.

7. Once a piece is wet, lay it on the outer edges of your paper to stick it to your board. You’ll want to lay it with at least 1cm on the paper and 1cm on the board, to make sure it sticks properly.

8. You will need to let your board dry overnight before painting it unless you want to work wet in wet straightaway.

9. You can use your paper as soon as it is dry. If you have done all the steps correctly it should be dried flat and ready to go!


  • Make sure your hands and the tub for the water are clean, or you may find problems with extra substances on your paper when you come to paint, that may ruin the final piece.
  • When placing your paper on the board, land it in the middle first.


  • You do not want to wipe off all the glue from the gummed tape, so make sure your sponge isn’t too wet while doing this.
  • Leave your boards upright to dry, as over time the water may run down to the bottom and allow for uneven stretching.
  • Use masking tape or other kinds of tape. The gummed tape is important as it is activated by water, other tapes will not stick.

You may need to have a few tries to get the process just right for you, but once mastered, stretching your paper is the key to having a beautiful, flat, finished piece. Good luck!

Experiencing problems whilst soaking and stretching?
Look at the link below for guidance.


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