I could not wait to test my theory. Before I ran on errands, I stuck a piece of watercolor paper in my sketchbook, I painted on it and let it dry. The type is 225 gms/m3, from the brand 4art. The moleskin is a sketchbook, and has approximately 140 gms/m3. After coming back it dried up nicely, ready for an examination.
The colors tested are;
- Cerulean Blue hue
- Ultramarine Blue
- Lemon Yellow hue
- Cadmium Red hue
- Veridian Green hue
The first thing that is noticeable is that the moleskin is yellowish, and the watercolor paper is white. When applying the watercolor, I tried to be abundant with water, and leave some saturated pigment drops here and there to see how they would flow.
What is interesting, is that with some colors there is a clear discoloring, where Cerulian Blue turns into Aquamarine Blue. The Ultramarine Blue almost turns into a purple color, and the Cadmium Red turns into a dull bloody / orange red. The Veridian Hue green turns into a lighter version.
The watercolor also flows differently where the watercolor paper naturally flows and evens out the pigment and the sketchbook leaves it where it is, introducing streaks of color or pigment puddles that do not mix well with the already present colors.
All but all it is safe to say I will not color much in this sketchbook anymore (it is called a sketchbook for a reason), and look for a nice A5 size watercolor hardcover sketchbook. I like to start a travel or nature journal some day, but the colors should match with what I would like them to be.