Wet Edge lets you add a unique watercolor effect. You can also draw watercolor-like illustrations with it.

Prepare an illustration with a painted base.

From ① the Material tool, select ② Material Patterns (Color).

This time, we selected ① hemp.

In order to obtain the texture of paper, turn on ① Repeat, to shrink the material and make the pattern appear finer.

Tap ① ✓ to apply the material.

After applying the material, open ① the Layer window and from ② blend mode, select ③ Soft Light.

From ① Brush window, select ② Watercolor (Point).

Open ① the Layer window, and to the base of the line drawing, add ② a new layer.
This time we set ③ the opacity level to approximately 25%. Turning on ④ Clipping lets you add shadows without painting outside the drawing.

Gently tap on to add shadows.

Once you are done adding shadows, open ① the Layer window, and over the shadow you just added, add ② a new layer and turn on ③ Clipping.

From ① the Tool Selection window, select ② Filter.

Select ① Wet Edge.

Drag the ① Slider to adjust Width and Strength of the water color border. When finished, return to the canvas with ② ✓ button .

By repeating this process, you can produce a picture that resembles a watercolor painting.