The Real Difference Between Gouache and Opaque Watercolor: A Painter’s Perspective
- Admin
- Apr 16
- 4 min read
The Real Difference Between Gouache and Opaque Watercolor: A Painter’s Perspective
by Charles Merritt Houghton
20 April 2025
It started as a casual question in the Art Students League of New York art store. I was describing a set of Kuretake “gouache” paints that weren’t giving me what I wanted. I asked the Tara, the manager: “Is there a difference between gouache and opaque watercolor?”
She insisted there was, but her description didn’t answer all my questions. So down the rabbit hole I went. My 1100 Watercolor Society colleagues use all manner of water media—transparent watercolor, ink, acrylic, and gouache. Surely I’m not along in my confusion, lumping gouache and opaque watercolor together and applying using the same techniques. They’re not. At least not in the ways that matter when pigment hits paper.
Here’s what I found—and why it matters.
Let’s Start with a Clear Distinction
From a materials standpoint, gouache and opaque watercolor are both water-soluble paints made with pigment and a water-based binder—usually gum arabic. But what separates true gouache is what’s added on top of the pigment and binder:
Chalk (or other opacifiers)
Higher pigment load
Matte finish
These additives change everything. A true gouache allows you to paint light over dark, just like you would in oil paint or acrylic. That makes it a workhorse for figure studies, design rendering, and any time you’re layering values.
Opaque watercolor, by contrast, might look the same on the label, but functionally it behaves more like transparent watercolor with just a bit more body. It’s often made to blend into watercolor workflows—adding highlights or visual punch, but not enough that you can layer lights over darks. Trust me, some fail miserably.
Painting Light Over Dark Simulating a Fast Drying Oil Workflow
Most watercolorists work from light to dark. (Not all, the amazing Wendy Artin plows straight into the darks… such courage!) You preserve the whites, build up shadows, and accept that any mistake made in the darks is there to stay. But sometimes—especially in mixed-media drawings, fashion and costume studies, and graphic work—you need to paint light over dark. You need to model form with layers of color, value, and light, then smack some highlights on top. That’s where gouache comes in.
When I switched from Kuretake paints (which had a slight gloss, weren’t thick, and resisted clean layering) to Caran d’Ache Swiss gouache, I immediately noticed the difference. The Swiss paints laid down flat, even layers. I could paint white over deep blue and get a clean result. Sounds luxurious. It was. But it differed in a meaningful way, I could lay one color over another.
And yet, I was still thinking like a watercolorist, by adding gouache into my transparent watercolors to punch up the coverage.
But could I pull off true light over dark? Yep, at least with my new paints, it worked like a charm. I’ve always admired goauche specialists like Nathan Fowkes. But using Kuretake paints his techniques were out of reach. New paints gave me new life.
Let’s Talk Terms: Opaque Watercolor Isn’t Always Gouache
Part of the confusion comes from the term “opaque watercolor.” Historically, it was used to describe gouache in the days of military illustration and academic painting. Today, though, it’s a marketing term. Sometimes it refers to gouache. Sometimes it refers to watercolor with just enough titanium white to appear opaque.
In brands like Kuretake, “gouache” or “opaque watercolor” is often geared toward calligraphy or decorative effects. At least, that’s how it feels to me. The finish is slightly glossier. The rewetting behavior is erratic. It’s not built for compositional layering—it’s built for single-pass application.
In contrast, Caran d’Ache and Winsor & Newton Designers Gouache seem to be engineered for coverage, layering, and control. These are workhorse paints, and they act like it. I haven’t tried all the brands, but these two have worked for me.
Why Water-Media Artists Might Care
Most artists I work with in the 1100 Watercolor Society blend tools and approaches. But if you’re reaching for a tube that says “gouache,” expecting to add highlights over darks, like shadows, you deserve to know what you’re getting.
If you’re painting layered compositions and need layering? Use true gouache.
If you’re adding final accents or want a painterly shimmer? Opaque watercolor might work—but expect limitations.
If you’re building a hybrid practice, mixing transparent watercolor with gouache, understand the strengths of each.
This isn’t about being purist. I’m not religious about my water media practice. Whatever works. But if you’re frustrated? Hope this article clears things up.
Closing Thoughts
Not all gouache is created equal. And not all “opaque watercolors” are gouache.
But the functional difference?
True Gouache lets you paint the light back over the dark.
That’s the differentiator. That’s the reason designers, illustrators, and yes—painters—still reach for gouache. If you paint in oils, and want a process which permits light over dark, true gouache is your friend.
So next time you’re in the store and that little voice says, “Wait, isn’t this just opaque watercolor?”—trust your instincts.
If you can, test it.
If you can’t? Buy 1 tube of a light/white and 1 dark color.
Give them a shot, paint light over dark. Did it work? Only then should you invest in more colors. This stuff gets expensive fast. Start with a couple tubes, not a comprehensive set.
If you have a trust fund? Dive in. Give the sets that don’t work for you to less fortunate artist friends. Karma counts.
Use whatever works for you. I’ve chosen. Caran D’Ache and Winsor & Newton for true layering. Kuretake? Bottom of the pile/Back of the closet.
And remember some materials help you, and others fight you. If the ones you’ve got aren’t working, it might not be you, it might be them.
Time to break up.
Comments