Good quality watercolor paper has a watermark that identifies the manufacturer of the paper. This image is from a sheet of Arches 140# paper. Note the company name, Arches, country of origin, France, and the infinity symbol. These are within the paper and visible on both sides when held up to the light but visible only on the right side with no back lighting. Also, if you look carefully, along the bottom on the right after the upside-down F, turning the corner, and going up a little on the right side are the words “AQUARELLE ARCHES” embossed in the paper. These you can see and feel on both sides of the paper.

When watercolor paint is brushed over the watermark, some of it may show. This image with paint applied over the watermark
is how you might see it on a painting. Here, I have purposely left some white of the paper showing and pulled the brush lightly over the paper so that you can see the watermark. Compare it to the next image. This one is of the same sheet of paper but with light shining on the back and, thus, highlighting the watermark. You can still see all of it. If you were to purchase a watercolor painting unmatted and unframed, you could hold it up to the light and see the watermark. But a framed painting may show little to none of the watermark.

Watermarks usually appear only in one or two corners of a sheet of watercolor paper, as well as on other fine quality papers, such as for printmaking. If the artist is using less than a full sheet of paper, it might be a section that has no watermark, so a painting on fine quality paper may not always have a watermark.

What appears on the back? Without back lighting, the sheet reveals only the embossed words. Here, I have painted over the area with the watermark, and you see only the backwards letters of “AQUARELLE ARCHES”; none of the imbedded watermark shows. (Held up to light, the sheet would show that watermark, but more faintly than when on the right side.)

Another type of watermark you may see when viewing art online appears prominently over an image to prevent unauthorized copying of the art. Various words are used (watermark, do not copy, the artist’s name, etc.). If you were to print that image, the watermark would print with it. Although usually the word is large enough to be noticed, it appears faintly so as not to interfere with viewing the art.