In other media, such as acrylic, the paint is held together with a binder, and you can layer opaque planes of color on top of one another. “But with watercolor, you’re dealing with pigment suspended in water, so its binder is relatively nonexistent,” Boyd explains. This material circumstance makes watercolors transparent––meaning that the white of the page will be visible through layers of color. “If you use a black watercolor pigment and it’s thinned with a lot of water, it will end up being gray because the white of the page will show through it,” Boyd says.
Watercolors can also be challenging because marks you make aren’t easy to erase or “fix.” For artists who wish to render a specific image, it’s helpful to spend a decent amount of time mapping out a plan with pencil before beginning, particularly because any whites in your piece should be the unpainted white of the paper you’re working on (not a white pigment).
The process of planning an image will be different for every artist, but for many, it will involve identifying the lightest and deepest areas of an image, so that layers can be built up without error. “It’s like grabbing ingredients for a meal. A lot of questions are answered in prep,” Blatt says.
For example, Boyd will softly trace out the deepest shades of a picture with a pencil, where he knows the marks will be covered up with pigment, whereas for the lightest areas, he’ll apply masking fluid to the page. Though it’s not necessary, masking fluid (which is essentially liquid latex) can help you block out areas of the page that you want to keep paint off of and stay white. Paint will glide over the latex instead of sinking into the page, and once you’re finished, you can peel it off to reveal the vibrant white of the paper.
To capture the darker shades of your image, the artists advise that it’s best to use more pigment, instead of more layers of paint or a deeper color. “If you’re rendering a shadow, or darkness, you won’t necessarily use a darker pigment, but more material, more matter, more pigment,” Boyd explains.