Update Aug 2019: They have clogged
Can you fill your waterbrush with watercolour paint?
That's a question I receive occasionally.
So I bought three Pentel Aquash waterbrushes to test, one for each primary colour. The colours I've used are from the Sennelier Aqua-mini set, namely Primary Yellow PY74, French Vermilion PR242 and French Ultramarine Blue PB29 + PV15.
You'll need an eyedropper or blunt needle and syringe also.
The watercolour paint I'm using comes in half pans. It's easier to use tube paint because they dissolve more readily. You'll want to create a concentrated mix to start with.
Watercolour is pigmented so the pigment will settle down with time. I'm not sure if this will clog the waterbrush badly or the waterbrush can be cleaned properly. Only time will tell.
The advantage of using waterbrushes is they are very convenient and portable. The downside is your control of water has to be good because water is always there. Having tissue while you're working allows you to absorb excess water easily.
This is the sketch I painted using the waterbrushes.
For the clouds, blue was painted first and the edges were soften with another waterbrush loaded with clean water.
I'm using mostly layering or glazing technique here, putting colour over colour to create the colour mix that I want. The reason for using glazing technique is because I want to keep the waterbrushes as clean as possible. I start with yellow because that's the colour that's easiest to get dirty, followed by either red or blue.
For this area, I squeeze out droplets of paint on paper before mixing them. This allows the colours to blend into one another nicely.
Glazing is a technique that can show off individual colours beautifully. You can almost always see the colours that were used to create that mix. This makes the washes look more interesting and varied. For the green, I painted with yellow first, and while it's still wet, I added blue.
Glazing technique requires more time. You need to wait for each layer to dry first before adding the second. Otherwise, you will disturb the first wash, unless that's your intention. And you'll also dirty the waterbrush you're using.
To build up darker values, sometimes you have to glaze or layer several times. When doing so, it usually means more water would flow onto the paper and that area will take longer to dry.
Using watercolour in waterbrushes like this pushed me to glaze or layer. Using different tools and mediums may sometimes change your process or workflow, and that's part of the fun when experiment with new ways of working. I don't use glazing technique often. When I was painting this sketch, I already have in mind what colour mixes I will use and how they would look. But the final look is very different from what I expected. That's because colour mixing with layering vs that in palette behaves different.
With a normal brush, I probably won't use glazing. But it certainly was fun painting this way.