Watercolour Paper De-mystified

Watercolour Paper De-mystified: The Essential Elements

Watercolour painting is a beautiful art form that requires a lot of precision, patience, and skill. However, what most people don't understand is that in addition to the paints and brushes, the paper used also plays a critical role in determining the quality of your artwork. When it comes to choosing the right watercolour paper, there are three essential elements you need to consider: surfaces, weights/thickness, and problem-solving techniques.

The surface of watercolour paper describes its level of texture or smoothness. There are different types of surfaces available, but the three most common ones are cold-pressed, hot-pressed, and rough. Cold-pressed is the most popular choice because it has a slightly textured finish that allows the paint to adhere better, giving your paintings a lovely, natural look. Hot-pressed paper has a smooth surface, ideal for detailed painting as it offers precision and sharp lines. Rough paper has a very textured surface that is excellent for creating more expressive and loose brushstrokes or washes. Most artists will usually start with cold-pressed paper, but make sure to experiment with different surfaces to find out what works best for your style and technique.


Trying to understand the weight of watercolour paper can be a confusing business. Lots of numbers abound...what do they all mean? Paper is classified by two weighing systems; grams per square metre of paper (gsm) and pounds per ream of paper (lb). Pads usually give weights of both, which can add to the confusion, but once you understand the classification, it’s easier to work out. The following list gives the main weights of watercolour paper, firstly in grams and then the equivalent in pounds.

300gsm = 140lb 425gsm = 200lb 535gsm = 250lb 640gsm = 300lb


Q: How do I stretch watercolour paper?

A: 1) Immerse the paper under running water until thoroughly wet {approximately 30 seconds}, taking great care not to touch the area you are going to paint as finger marks can show up in the wash.

2) Place the soaked sheet on a sturdy waterproof board. NOT M.D.F!

3) Moisten some gummed tape and place round all four edges, making sure it isn’t lifting.

4) Blot excess water with a clean paper towel and leave to dry on a slight tilt overnight. Don’t be tempted to speed things up with a hairdryer!



Q: Why does my watercolour paper go wobbly?

A: When applying water to paper, it moves and buckles (known as cockling), because applying moisture to the sheet causes one side to expand slightly. The other side remains dry due to the sizing in the paper and does not expand. The paper does the only thing it can, and bows and buckles.

Q: What can I do to avoid this?

A: General rule of thumb: the wetter the wash you are going to apply, the greater the need to stretch the paper, or to have a heavier weight paper that will withstand the water that is applied. A minimum weight of 300gsm or 140lb is recommended.

Q: Why does the tape pull away from the paper when it’s drying?

A: 1) It’s possible the tape has been oversoaked removing too much glue from it.

2) There is a problem with the absorbancy of the paper. This can be caused through accidental contamination with detergents (when stretching the paper over the kitchen sink for example) or over handling whilst wet. Both can affect the sizing of the paper.

Q: Why does my paper act like blotting paper?

A: If it happens after stretching, the most likely explanation is contamination with detergents. If the paper is older, The sizing can deteriorate over time, particularly if the paper has been left in hot, humid or very cold conditions.

Q: Why are dark marks appearing when I do a wash?

A: This can usually be attributed to finger marks made when over-handling the paper when it’s wet. Touch only the edges when you are stretching it.

Q: Why are white lines appearing when I do a wash?

A: This is normally caused by a puddle of water being left to dry on the paper. As it dries, it leaves a ‘tide mark’ which shows up as a white line when you do a wash.

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