Color pencil loves watercolor (and gouache) because they dry to a surface that still allows the application of color pencil.
And when you use the color pencil with light pressure on top of dry watercolor passages on a slightly textured paper you get a lovely broken color effect. (You can see that in the shadows , tip of the nose, and places in the beard on today’s sketch.)
I’m working on the OLD Gutenberg paper (and I don’t like the revised paper now sold under that name) but you can do the same thing with any cold press watercolor paper you like to us.
Besides adding interesting texture color pencil on top of watercolor can speed up your drawing time. Allowing you to do your additional layering without having to wait for paper drying time between the color pencil layers.
I also find that applying glazes of watercolor first allows me to set up a color base to work up from. And it hides the paper color in one stroke not the many that color pencil takes.
I also find that it’s useful to write down color combinations when you’re working with color pencil. If I’m doing a quick sketch I don’t get out a full range of color. I use the color pencils I have at hand. This means I might make some oddball color blends that I want to remember for future, but if I don’t write them down I might not remember them exactly!
In this view of the fun page spread you can read my notes and see my color swatches. I’ve been talking to my Patreon subscribers about making color notes. This is another example that I thought of to share.
Oh, and a quick word about using color pencil this way on some brands of watercolor—if you use watercolor opaquely (as I often do) the resultant opaque paint may be too shiny and slick—because of the ingredients in the watercolor to take kindly to the application of color pencil. Too much gum Arabic or glycerin for your current purpose. That’s when it’s best to pull out the gouache if you want to work opaquely. The best brands of gouache will leave you with a love mat surface to draw on. But if you’re using watercolor transparently then there won’t be a problem, no matter how the watercolor brand you use is formulated.