Your Questions on Gouache

A lot of you have asked me questions about gouache, so I've gathered up the answers here for the benefit of everybody:

Carlos says, "After watching Gouache in the Wild, I'm finally going to buy some gouache tubes. I was wondering if the same colors list you posted on the Watercolor in the Wild post serves as a guide to build my first set."

Carlos,  those colors would serve you well. Basically a high-chroma yellow (such as a Permanent Arylide Yellow), a bright red (such as Flame red), and then earth color versions of yellow and red, such as yellow ochre and burnt sienna or Venetian red.

Then you'd want to get a couple of blues. I like cobalt, ultramarine, Prussian, and cerulean, but I rarely take more than two of them at a time into the field. I also like having Viridian and a brilliant purple. Again, these are mainly for limited palettes, or if for some reason I need high chroma (saturation). And of course you'll need white. And black, especially if you ever want to paint in pure black/white grisaille.

Concept sketches for Scientific American "Ascent of Mammals."
Watercolor, gouache, and water-soluble colored pencils.

Mary says, "I sketch in watercolor with a minimal kit (Maria's tiny card-sized kit) and would love to be able to bypass colored pencils if possible. Do you think it's possible to sketch as quickly and realistically without them?"

The answer is yes, definitely. Painting with pure watercolor is totally fine and you can get any effect you want with a brush alone. You might want to use the brush both wet and dry -- the drier brush, splayed out, will give you all the textural effects you might otherwise get with a pencil. The only problem with those extremely tiny kits is that you can't mix generous washes of either transparent or opaque watercolor for skies or other large areas.

Vodka Fashion says, "I just stared implementing gouache in my paintings. My question is, do you travel with the actual tubes, or have you made a gouache travel kit? I tried making a travel kit, but the paints dried out."
I travel with a small set of tubes in a plastic bag, anywhere from two tubes (black and white) to about eight or 10 tubes. Sometimes I carry just a limited palette of three colors plus white. That forces me to do what I can with those colors. Although you can squeeze them into a watercolor-type palette, in advance, let them dry, and then rewet them, they don't reconstitute into the smooth consistency that they had when they came out of the tube. And there's the problem of them breaking up. If you just want to solve that breakup problem, you can mix them with more of the water-soluble glue-like binder gum arabic, which you can get in liquid or powdered form.

Suzy Powell says: "So you just rewet? Where I live we have 00000% humidity. Haha (West Texas)
No, I don't rewet dry gouache except as a last resort. I've used gouache in low humidity and it does dry quickly. It can get very frustrating on a hot day in the sunshine in a desert, in which case oil would be a better medium. But for gouache, using a damp paper towel under the paint you squeeze from the tube will help it last longer. You can also extend the time by misting your palette with a little water from a spray bottle. But once it's totally dry or used up it's best to reset the palette by cleaning it off and starting with freshly squeezed paint. Don't keep dabbing at the spot where the paint used to be.

Matt Urbanowicz says: "I wanted to ask about the colours bleeding: I have a problem that while painting in gouache or poster colours when adding layers I tend to pick up and smudge the colours from the layer underneath, even when it's dry. Am I doing something wrong?

Matt, yes, gouache will tend to pick up if you put a wet layer over a previous layer, especially if you work it with the brush at all. The fact that the surface can be reactivated can be a good thing if you want to soften edges after the fact. But if you don't want those previous layers to come up, there are two remedies. The first is to lay down every stroke quickly and without any extra brushing. Make it your motto to "Make every stroke count." Or "Think twice, touch once."

If that doesn't work, you can use Acryla Gouache or Casein, which have a closed surface when they dry.

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Previous posts about gouache
Seven gouache hazards and how to avoid them
Gouache ingredients—info from manufacturers
Questions about gouache

Video tutorials
Gouache in the Wild

The Mammal that Ate Dinosaurs

Watercolor in the Wild