Watercolor paper

Watercolor paper is paper that is made to take a lot of water and can be made from either wood pulp, cotton, or a combination of both.
Top grade watercolor paper is 100% cotton and acid-free, but you don't need the absolute best to make beautiful art.

Hot vs. cold-pressed

Hot-pressed watercolor paper is smoother in texture and is easier to stamp on.
Cold-pressed watercolor paper is a little bit rougher. If you want to stamp on this type of paper, which you absolutely can, a stamp positioner comes in handy so you can restamp the bits that didn't transfer well.

Block, spiral bound or sheets

When watercolor paper is sold in a block, it means two, three, or four sides will be glued together. There will always be one place where there isn't any glue. To separate the sheets, put a bone folder, ruler, knife … in the gap and slide around the block until the sheet is free.
If you buy spiral bound watercolor paper, keep in mind the final size of the paper might be slightly less than what is displayed on the packaging or cover.
Some watercolor paper is sold in loose sheets of different sizes. Keep in mind that if you want to tape down your paper on all sides onto a surface (to prevent your paper from buckling), you should take a paper size that is slightly bigger than what you want your final paper size to be.