Paper is super important in watercolor painting. Aside from having something to paint on, the transparent nature of watercolor helps show the texture of the paper you are using.
Acid-free is key if you want your painting to last.
I have a variety of brands of the same type. They are all pretty different from each other. Some have nicer textures but can't hold up to tape or erasers as well. I try to be kind to all of them but "happy little accidents" do happen. ;)
There are 3 types of watercolor paper surfaces:
Hot press (smooth, good for fine detail work)
Cold press (has texture, best for beginners)
Rough (lots of texture)
This watercolor paper is smooth with a very fine texture. If you have some just run your hand over it. Yep. Super nice. Is this getting awkward? ...Ok, basically it's like a newly paved road. It's just nice. You know what I mean!
Hot press is great for fine detailed work and times where you don't want a lot of texture added to your painting. You have more control of the watercolor since the surface of hot press is uniform and smooth.
Cold press is great for beginners. It's a good familiar, reliable dirt road. It has a nice amount of texture and gives that classical watercolor painting look. You can have fine details on it and have the watercolor work with the paper's texture at the same time.
Off-roading right here. Not that it is a bad thing! Rough watercolor paper is as its name states. Rough. Lot's of texture. It is a lot harder to sketch on and get details without the bumps and crevices, making the decisions for you at times. You may not always like those decisions. Other times you'll be pleasantly surprised. That is what makes this watercolor so fun to work with. It is pretty dramatic.
I had a much easier time doing details on the hot press paper. Cold press was a little bit harder to sketch on but I love the texture and granulation that happened on some parts of it. As for the rough. Well, baby Yoda himself looks a bit rough but that is more of me not using rough paper very often. Someone once told me a bad surgeon blames his instruments. So it was not the paper -- it was me! (*whispers* Does this admission make me a good artist by default then?)
Here are a few more samples of the same paint on the different paper surfaces. All of them were wet-to-dry except for the blue. It was a wet-to-wet technique. I painted a circle with water and added 3 blue dots of paint and let it bloom and bled on its own -- untouched.
The hot-press bled/bloomed the most. Having a smoother surface does make the water sit on top, allowing the paint to flow freely. The cold-press and rough absorbed the water, and the texture made it harder for the paint to flow in the shape of the water.
Now go and get your papers and start painting!