Watercolor is obviously a water-based medium. And water plays an essential role in every painting technique. During the painting process, the paper surface goes through different cycles of wetness.
Wet to dry, dry to wet, etc.
So it’s easy to get confused about when precisely the paper needs dampening, especially for artists new to watercolor painting. They sometimes pick up the wrong habits 🙂
Moistening the paper is only done for specific reasons.
In this article, I’ll explain the when the why… and all the rest!
Should you wet watercolor paper before you begin painting?
The watercolor paper only needs to be moistened prior to painting if you intend to use a wet-on-wet painting technique. Wetting the paper can lead to buckling, making brushstrokes challenging to control because of the resulting bumpy surface.
I’ve seen newbies lavishly splashing water onto their sheets of watercolor paper at the beginning of each new project! This is probably because they’ve seen other artists do this when they prepare to paint a new subject.
Pre-wetting the paper is not required!
There are only a few reasons to moisten the paper surface before a painting:
- If you need to apply a wet-on-wet technique.
- When you’re stretching the paper in preparation for a future painting.
- Because your paper is poorly sized.
Let me explain those last two cases…
- Stretching is when you pre-soak watercolor sheets, tape them down to a board and then let them dry. The paper expands when wet, then dries when it contracts. Fixing down the edges of the soaked sheet makes the paper tight like a drum when it dries out.
As a result, you get a nice smooth work surface even when you paint a big wet wash!
I rarely stretch my watercolor paper. It can be pretty time-consuming to prepare sheets beforehand. I don’t always have the patience 🙂 And it isn’t strictly necessary.
- Secondly, the surface of the watercolor paper has a coating called “sizing.” Manufacturers often use gelatin (a transparent water-soluble substance). The sizing modifies the porosity and absorbent qualities of the surface so that it doesn’t soak up the paint like a sponge.
Sometimes a batch of watercolor paper can have uneven or blotchy sizing. You can brush the surface with clear water using a large brush or a sponge to fix this. Because the sizing is water-soluble, this helps re-distribute the sizing all over.
Reasons not to soak paper at the start of a painting.
As mentioned, an excess of moisture makes watercolor paper warp and deform. This can make it tricky to control the movement of wet brush marks because they flow around the bumps on the surface. (This is why some artists prefer to stretch the paper in advance).
A wet surface also behaves differently to dry paper. Painting a detailed or accurate shape when the surface is damp is impossible. Colored pigments spread out from the brush marks and disperse quite far (this effect is intentional when painting with a wet-on-wet technique). On the other hand, a brush stroke on dry paper has crisp, well-defined edges.
Finally, if you soak the paper excessively, you will wash off some of the surface sizing. The sizing is there to help balance the permeability of the paper so that it doesn’t get absorbed deep into the paper fibers.
An over-enthusiastic brushing with water alters the surface sizing and the handling properties of the paper.
When should you wet watercolor paper?
The most common valid reason for pre-wetting paper is when applying a wet-on-wet technique (painting with a loaded brush onto a wet surface).
Wet-on-wet is a unique technique that allows the colored pigments to disperse over the paper’s surface. It’s a unique characteristic of watercolor painting. You can achieve some beautiful effects using this approach.
Why do artists wet the paper before painting?
Artists who start out with a dampened painting surface usually do this to establish a background. You’ll see this quite often in landscape painting, but It can be done on all types of subjects.
Using this wet-on-wet method allows artists to start building up underlying shapes of color and tone. It produces a smooth, even distribution of colors to establish the subject before the following layers of paint.
The result is uniform and soft, with very few or no brush marks. A single color can produce a smooth and progressive tone change from dark to light (graduated wash). Using more than one color creates amazing soft-edged multicolored patterns (variegated wash).
Wet-on-wet is an excellent technique that is singular to mediums like watercolor.
I would encourage you to take advantage of it… Deliberately 🙂