choosing a watercolor paper
There are several things to consider when choosing watercolor paper.
The weight: 300 grams per square metre or 140 lb is usually considered the minimum for watercolor painting. Thinner, lighter paper is cheaper, but you will have buckling problems, especially with wet in wet painting. To get around this buckling problem, you can try stretching the paper before painting. Search YouTube for videos that show you how to do this. Heavier papers are easier to work with.
Material: 100% cotton paper is usually considered best for watercolor painting. Alternatives include cellulose (wood pulp), and other plant fibres such as sugar cane or bamboo. Avoid drawing paper or mixed media paper as these are not designed for watercolor paint.
Surface texture: hot pressed paper is smooth. It is suitable for fine details and a more illustrative style. Cold-pressed paper has more texture; it is sometimes called Not. Some manufacturers also make Rough paper. The Rough paper is best for loose impressionistic styles.
Sizing: All watercolor paper has sizing added either on the surface, internally, or both. Sizing is a kind of glue added as part of the paper manufacturing process. It helps bind the fibers in the paper. The sizing also makes the paper slightly waterproof. As a result, it takes a minute or so for the wet paint to sink into the paper, which gives you some time to work with the paint. Note for Vegans: some sizing is animal based so you need to check that. I have a blog article on Vegan friendly watercolor supplies.
The left image above is painted on Rough paper. I’ve expanded part of the painting to show the surface texture. The image on the right is on smooth Hot Pressed paper. Some people prefer one or the other.
Don’t be afraid to experiment with paper.
I have a short watercolor landscape painting video lesson and digital art book (for inspiration) on my Patreon Shop. I also have a course on Impressionist Watercolor Painting on Udemy.