Yes, traditional gouache can reactivate with water, even after it has dried. It’s one of the things that makes gouache such an interesting medium to work with, but it can also take some getting used to.
When I first started painting with gouache, I quickly learned that “dry” doesn’t necessarily mean permanent. If you add water or wet paint over a dried layer, some of that color can become workable again.
Sometimes that’s exactly what you want. Other times, not so much.
Why Does Gouache Reactivate?
Gouache is a water-based paint. Unlike acrylic paint, which becomes water-resistant once it dries, traditional gouache can usually be softened again with water.
That means paint that has dried on your palette can often be reused. Add a little water, give it some time to soften, and you may be able to paint with it again.
It also means dried paint on your artwork can reactivate.
If you brush a wet layer over an area you’ve already painted, your brush may pick up some of the color underneath. That can cause the two colors to blend or make the lower layer look disturbed.
Is Reactivating Gouache a Bad Thing?
Not necessarily. It can actually be useful.
I sometimes take advantage of it when I want to soften an area, blend an edge or make a small adjustment to something I’ve already painted. Being able to go back into a dry layer gives gouache a flexibility I really enjoy.
The challenge comes when I don’t want the first layer to move.
For example, if I’ve painted a dark background and then try to add a lighter color on top with a very wet brush, I can accidentally pull some of that dark paint into the new layer. Instead of getting a clean light color, I may end up with something muddy.
I’ve learned that the amount of water on my brush matters just as much as waiting for the first layer to dry.
Sometimes reactivation can actually work in your favor. With my goldfish painting below, for example, pulling some of the dark blue background into the white, flowy fins helped give them a more translucent look.
How Do You Paint Over Gouache Without Reactivating It?
You can’t always prevent gouache from reactivating completely, but a few things help:
- Let the first layer dry completely. Painting over damp gouache will move the paint much more easily.
- Use less water in your next layer. A wetter brush is more likely to disturb the paint underneath.
- Try not to overwork the area. A few deliberate brushstrokes usually work better than repeatedly brushing over the same spot.
- Use thicker paint for lighter details. If I’m adding highlights or light colors over something dark, I usually want the paint fairly opaque rather than heavily diluted.
And sometimes I simply leave an area alone and come back to it later. Gouache has taught me that continuing to fuss with a section isn’t always the best way to fix it.
Can You Rewet Dried Gouache on a Palette?
Usually, yes.
One of the nice things about traditional gouache is that dried paint doesn’t necessarily have to be wasted. You can often add water and work it back into a usable consistency.
How well it reactivates can depend on the brand, how long it has been dry and the particular color. Freshly squeezed paint and reactivated paint may not feel exactly the same, but dried gouache can still be very usable.
This is also one reason I enjoy working with jelly gouache. I keep the paints moist when I can, but if the surface begins to dry, water can help make the paint workable again.
Gouache Takes a Little Practice
Reactivation isn’t the only thing that took me some time to get used to. One of the biggest lessons I’ve learned with gouache is that the color you see while you’re painting isn’t always the color you’ll have once it dries.
Lighter colors tend to dry darker, while darker colors can dry lighter. I’ve learned to keep that in mind when mixing colors and building layers, especially when I’m trying to match a color I’ve already used. Because of that, I usually mix a little more paint than I think I’ll need and set some aside in a small airtight container. It saves me from trying to recreate the exact color later, especially when I’m adding shadows, fixing a mistake, or cleaning up lines as I put on the finishing touches.
The same is true of reactivation. Once I understood that a dry layer could become workable again, I stopped fighting the paint quite so much.
I learned when to use more water, when to use less, when to let a layer dry and, maybe most importantly, when to stop brushing over the same area.
That’s part of what I enjoy about gouache. It can be forgiving enough to let you go back and make changes, while still making you think about how each new layer will interact with the one underneath.
Like most things in painting, it gets easier the more you use it.