There are two brands of watercolor paper that I predominantly use—Arches and Lanaquarelle. It’s difficult for me to recommend one brand over the other since both have their advantages and disadvantages. Both brands create a quality product that stands the test of time--in this case before the 16th century.
The accessibility and quality of Arches make it by far the most popular brand for beginners and professionals alike. Arches paper has a crisp parchment feel to it, with a high level of gelatin sizing that causes the color to sit on the surface of the paper. This helps create bright colors and sharp edges. This paper also holds up well to layered washes, scrubbing, scraping and general reworking of the surface. Arches makes two colors, natural white, which is a slightly warm off-white, and bright white, which is a cool white that can produce brighter colors. I prefer the natural white because it gives a muted unifying effect to my colors.
While Lanaquarelle isn't found as readily as Arches in art supply stores, it is easily found through online dealers. Lanaquarelle paper has a unique “fabric” quality to the surface. It has a lighter gelatin sizing which causes the colors to sink in to the fibers of the paper rather than sitting on top as they do on Arches. Having the colors sink into the fibers creates an interesting depth, and causes the paper to feel more a part of the finished artwork. Edges become beautifully diffused when painting wet in wet on the “fabric” surface. Paintings on Lanaquarelle paper are akin to frescos where wet paint is applied on wet clay causing it to meld and became part of the final surface. Arches on the other hand is more akin to painting on gessoed canvas where the paint sits on top of the painting support.
While I prefer the final quality of a work done on Lanaquarelle, these paintings take longer to execute. Because colors absorb and fade into the surface, it requires many more layers to build up value. For this reason I often find myself foregoing the preferred quality for the sake of speed and reaching for Arches paper instead.