Watercolor painting typically involves using a lot of water. Paper can handle that, but one of its properties is that it expands when wet. When the paper expands, it results in "bumps and hollows." Pigment will have difficulty adhering to the bumps, while it will collect in the hollows. This doesn't always achieve the desired effect. When the paper dries, however, it doesn't always shrink back evenly, so annoying bumps may remain. To solve this problem, you need to stretch paper lighter than about 300gsm for watercolor painting. |
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