Watercolour artists stretch their paper, primarily to prevent it from buckling or deckling when water is applied in large quantities either in preparation for paintings or when a large wash is applied. This happens because paper expands when it is wet and this expansion can be reduced or eliminated by wetting the paper thoroughly then fixing the edges to a board, usually with brown gummed paper tape or with staples from a staple gun. I prefer to use gummed paper, which may not be as secure, because (unlike with staples) the board is not damaged and can be used repeatedly.
300gm paper smaller than about A4 size does not, in most cases, buckle enough to require stretching, and I generally only stretch paper larger than about A3 because, for smaller sizes, I find blocks of paper which are gummed all round quite satisfactory.
What type of board should be used?
Many board types are suitable for stretching paper on. Probably the most durable is “Oil Tempered Hardboard” or high density fibreboard, “Gator Board” is a paper coated board which is light and stiff and great to transport or use but perhaps not so durable. MDF or ply (over 5mm thick) is satisfactory but should be sealed with polyurethane, or similar, to prevent it from disintegrating.
How to stretch your watercolour paper (Quilliam’s method)
- Put 3 to 6cm of water into your bath or a large tray.
- Slide your paper into the water so it is fully immersed
- Tear four pieces of paper approximately 5cm longer than the sides of your paper
- Your board should measure at least 5cm larger than your paper all round
- Moistening the board by wiping a damp sponge over it may help the tape adhere
- Once the paper has been in the water for around 10 minutes lift the paper from the water by one corner and hold it up so the water drains off the opposite corner
- When the paper has almost stopped dripping lay it flat and square on centre of the board
- Take your gummed paper tape, one piece at a time, and place it into the water briefly (about 1 second is sufficient)
- Drag the wet paper between two of your fingers so that most of the water is removed but you have totally wet paper
- Apply the gummed tape to the edge of the paper so that approximately half its width is on the paper and half on the board
- Press the gummed tape down firmly by sliding your finger along the tape
- Repeat for the other three sides
- Leave to dry in a warm spot but not in the sun or in front of a heater – the boards can be left flat or standing on their edges
Some people recommend patting the paper surface dry but I am always worried that I will remove too much of the surface sizing.