Have you ever been painting along, happy as can be, and noticed a chalky film creeping into your color? I have. The first time it happened to me, I was sure my paper was rubbing into my paint. So I went digging — and it turned out the paper had nothing to do with it. It was the paint.
Here’s the thing. Glazing, or layering, is everything in watercolor. To really succeed with this medium, you have to learn how to glaze. But there’s one piece of glazing that matters just as much, and it trips up beginners and plenty of experienced painters too: transparency and opacity.
What Do “Transparent” and “Opaque” Actually Mean in Watercolor?
Some watercolors are transparent. They seem to sit on top of the paper and let a lot of light pass right through them. Opaque watercolors are the exact opposite — very little light gets through, which makes them far less effective when you’re layering.
Once you know which of your paints is which, that chalky film stops being a mystery.
How Transparency and Opacity Affect Your Painting
So the next question is: how does this actually affect your painting? In a few different ways.
- Knowing which of your colors are transparent and which are opaque helps you avoid painting a chalky film onto your work in the first place.
- Transparent colors mix well with other watercolors, whether those colors are transparent or opaque. In fact, mixing a transparent color into an opaque one can tone down its chalkiness.
- Opaque colors mixed together can turn muddy on the paper. If you’re after a muddy texture or background, that’s useful to know. If not, you’ll want to avoid combining them.
- When you paint an opaque color over a transparent one, that top color is usually easier to lift or remove than a transparent color painted over an opaque one.
How to Tell If Your Watercolor Is Transparent or Opaque
Now you’re probably wondering how to figure out whether a given watercolor paint is transparent or opaque. There are two ways.
First, most watercolor paint manufacturers tell you directly whether a paint is transparent, opaque, or semi-opaque — which means exactly what it sounds like: a paint somewhere in the middle.
Second, you can test it yourself at home with a simple exercise. Paint a long horizontal black stroke on a scrap piece of paper and let it dry completely. Then paint your watercolors in short vertical strokes on top of it. If a color appears to sit on top of the black stroke, it’s opaque. If it appears to sit underneath the black stroke, it’s transparent.
So now you know. Happy painting, and I’ll see you next time!
Transparency is only one of six things your paint is quietly doing on the paper. If you want the rest of the picture — granulation, staining, pigment count, mixability, and lightfastness — I broke all six down in Watercolor Paints – The Ultimate Guide for Absolute Newbs.