Saturday, December 8, 2018

Combining watercolor and gouache

Marko asks:
"I just wanted to ask you about painting process when combining watercolor and gouache. Is there some procedure, or the right way to paint gouache over watercolor, or I just switch to gouache? Is it OK to do first layers with watercolor (like underpainting) and then, if it is that simple, to paint over that with gouache? Also is it possible to do glazes with watercolor over gouache? To twist the procedure?

Marko, First off, there's no right way or wrong way to combine watercolor and gouache. But you don't really need to switch between them.

It might help to think of gouache as a very close cousin of watercolor. In fact, gouache IS watercolor—if you use it without white.

That's because, compared to the days of "designer colors," nowadays, most modern manufacturers don't add much in the way of opacifiers to their paint, but instead give you a lot of pure pigment. Likewise, watercolor essentially becomes gouache when you add white to it. 

So in terms of procedure, you can start your painting with gouache used transparently and gradually bring in opacity with thicker paint and more white as you need it.  That's what I did in this painting, for example.

(Link to video on YouTube)
Regarding your question about doing watercolor glazes over gouache: It is theoretically possible if:
a) The layer of gouache is absolutely dry.
b) The glaze isn't too wet.
and c) You lay it down in one stroke with absolutely no additional touching.

If you tend to be someone who noodles around with a glaze after laying it down, you'll lift previous layers. If that's a problem, you can use an acrylic gouache, which will has an acrylic binder, and will seal between layers.

I would suggest painting a still-life object using black gouache alone, using water to thin it for your lighter tones. Then try painting the same thing with black and white mixed for the gray tones. Try this test and see what happens. You'll learn a lot.
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Val Myburgh Art said...

Hi James, why would one use acrylic gouache instead of acrylics? Please will you explain the difference between the two.
Thank you.
Val Myburgh

James Gurney said...

Acrylic gouache really is acrylic, favoring opacity and a matte finish. Acrylic paint comes in a lot of different formulations.

Matt Dicke said...

I have glazed over gouache with a brush. It is tricky but doable. The easiest is to use an airbrush to glaze. I saw Jeff Watts do this on a you tube video. Very fast and effective way to shift color and push back an area that is too light. I have done it as a big wash over a whole underpainting it works to unify the painting as a whole and soften edges. Yeah it can lift the paint but it adds cool happy accidents and I find it is worth the risk. Key is not to go to dark/opaque and loose everything- well one might want that? Alternatives are to also use fixative then glaze on top. Happy painting.

Unknown said...

As James sad, there really are no right or wrong ways to do this, but I thought I'd chime in because I use my gouache a little differently than James (and Matt).

Gouache really is just an opaque watercolor, but the differences in opacity can be different depending on the colors that you use. James says as much.

When I paint, I typically paint on a white gouache 'ground', or rather I coat my board with it and then paint on top of it. I use a smooth bristol board rather that traditional watercolor paper because this allows the color on the top to be a little bit drippy. You can use any manor of watercolor or gouache on this ground as some of the ground will get absorbed into the color. It makes finding the right color a bit tricky, but the benefit to using the bristol board and ground is that one can 'erase' the color where there are more opaque whites by using a damp brush and wiping away the areas that one wants to be cleaner. Another advantage to this is it allows you to 'glaze' over those lighter areas (because they are now the white of the paper). It is almost akin to oil painting on canvas or board and wiping away the paint with turpentine. If you are interested, Burt Silverman has a good book on the subject called 'Breaking the Rules of Watercolor'. It's a good read, but takes some practice to understand.

Another way to 'glaze with gouache or watercolors is to paint your painting and then if there is an area that requires slightly more delicate color, to paint that section out with white gouache and then go back on top of that with light glazes. It is similar to what Matt describes above. I think that James has done this in one of his videos as well, but I just cannot remember which one.

Best, Michael