Comparing Gouache to WaterColor

WHAT IS GOUACHE (pronounced gwash)

Below is a link to an article that explains the good points about gouache.

10 Reasons to Love Gouache

https://paintspot.ca/top-10-reasons-to-love-gouache-painting/

Without looking at the article, however, basically, gouache uses the same binder (gum arabic) as most watercolors do. However, instead of being transparent, it varies in terms of opaqueness, and has a matte finish. Cheaper brands will use a "matifier" to make it more flat and increase opaqueness. Better brands use pigments that don't require additives.

Many watercolorists will have white gouache in their paint box. It isn't acceptable in shows that are pure transparent watercolor, but other than that, it's OK to use. We use it for things like spattering on snow, or recovering some small bits of white. Because it is opaque, it shows white over even dark colors.

But gouache has been used for a long time, and was popular with illustrators because it can be worked and reworked, and especially for the mat finish needed for early color printing processes. Those collectable 1950's paintings of Cadillacs with a glamorous model in furs were usually done in gouache.

Gouache comes in a lot of colors. Several paint makers have top quality gouache: Holbein, Winsor Newton, M. Graham, and DaVinci are a few. Some prefer a gel-like gouache called Himi that comes in a tray that looks like an ice cube maker with a lid that prevents the paint from drying.

I have a handout that shows a comparison of watercolor vs. gouache qualities. You can't read the entire right hand side bc I am not that computer savvy.

	Gouache	Watercolor
Qualities	Opaque-covers pencil marks	transparent--pencil marks show
	consistency of acrylic; paint thin to thick	painted more thinly
	dries quickly	drying time dependent on how much water
	can be lifted/reconstituted	more easily lifted and reconstituted
	Can flake if too thick
	Must change water often, becomes cloudy
	Doesn't buckle the paper bc less water used
Materials
Brushes	multi-media or synthetic	Synthetic or natural
	Is harder on your brush
Paper	Can use lower quality, not 100% cotton	100% cotton or yupo
	Canson XL, hot press, less expensive
	bristol board, etc. Even black or colored paper
	Smooth papers. Hot press if water color
Paints	Gouache; can be mixed with some watercolor	Watercolor
	Has the same base as wc, (gum arabic)	no mattifier added; usually gum arabic
	but adds mattifier in cheaper brands
	some DRY darker, some lighter, so test	All dry lighter
	come in a variety of colors	larger selection of color
	Is opaque, but some colors are more transp.	transparent, but some are less so.
	Cost a little less, but you use more paint	Use less paint usually
	Matte finish.	Reflects light from paper.
	No additional qualities	Additional qualities such as sedimentary, staining,
	Can be bright colored	lifting, etc.
	dries quickly	needs more drying time
Color mixing	Adding white for lightening color	Lighter color achieved through adding water.
Method/technique	In layers. may paint light over dark	In layers and glazes. Must leave whites.
	Can water down for underpainting.	can use salt, backruns, saran wrap, other techn.
	can't use salt and certain other for texture
Blending	Is more like blending oils & acrylics	Blending done wet in wet, on paper or palette.
Paint consistency	Very little water. Enough to make paint	Thinner consistency, usually much more water.
	flow smoothly.
	Can crack if too thick.
Watercolor and gouache can be used in the same painting with care. You can do a watercolor underpainting and
use gouache over it. Or do a watercolor painting and use gouache to restore some whites. It will appear more chalky
so must be done sparingly. You can spatter snow in a winter scene; spatter yellow flowers over a field.

The first thing to do with any new toy...I mean paint... is to swatch it out and see what the color looks like dry. With gouache, you have another motive...to see how opaque each color is. Even though it is considered an opaque medium, just like anything else, some colors are less opaque. Yellow, for example, just can't help being transparent, whether it's acrylic, oil, watercolor, or gouache. 

Make a long black line, about 1/2 inch wide, across a piece of scratch paper. Try each color painting over this black line. Make sure you label the colors. You will also notice that gouache tends to dry differently than watercolor. It dries FASTER and usually DARKER...except your dark colors, like black, will dry LIGHTER. Swatch and see.

The above example is from a two sets, M. Graham on the left, and Holbein on the right. . Your most opaque colors are white, cobalt blue, and black.

Reference photo from pmp

It is possible to paint in thin washes, like watercolor, but it is more often painted thickly, with much less water. Because of this, you can use a cheaper paper, like Canson XL or even Bristol paper. On a white surface, the colors look very bright and clean. When painted on a darker surface, you often need to add white to a color to intensify the opacity. 

I'm going to show this same toucan painted once in gouache (top photo) and once in watercolor (bottom photo)

Here is the sketch

I am using primary yellow, primary magenta, cyan, white and black from the Holbein set of primary colors. Students were using a student grade set from Master Touch. ($10 at Hobby Lobby)

Sketch onto hot press paper or Bristol or inexpensive watercolor paper with little tooth. Gouache doesn't play well on textured paper. Squeeze out enough yellow to cover the beaks and make a separate bit of orange (either out of tube or mix magenta and yellow). Cover the top or entire beak yellow, then (I turn my paper upside down for this) add the orange along the middle line of the beak, and encourage it into the top beak, pulling it up either with a small brush or fan brush, to make the "tooth" marks.

Then paint the entire bottom except for the tip of the bill with deep red orange.

What you will notice: The gouache will start to dry on you quickly. It doesn't leave much time for blending. When dipping your brush into the paint, you only dampen the brush to pick up as much paint as you want. You don't thin out the paint a lot. Only enough to allow you to make smooth strokes without dry marks. Also paint yellow and orange around the eye. I've painted a little white mixed with yellow under the eye. 

After the bill is dry, I added the dark orange stripe on the top of the beak and then the black on the tip and on the stripe near the eye. You can paint over anything if it is completely dry. I also used cyan and covered the entire eye area.

I finished painting the black on the feathers, which goes quite quickly. Gouache usually does not require a lot of layers to get dark. I mixed some white with orange to tint some color for the serations on the beak. With a very small brush I painted in the line between beak parts with small serations.

Here is a closer look. After painting the white line, I used a dark red orange to paint UNDERNEATH those serations to appear to be a shadow.

To finish I filled in the center of the eye with black and outlined around the eye in black.

(I used marker because my hands are too shaky for a tiny brush here). I then hilighted the center of the eye with a comma of white, and added a little on the black beak. 

To demonstrate that gouache can also be used more wet, like watercolor, I watered down blue and green. I wet the paper, then loosely applied the colors and added salt while they were still shiny. This was my result. 

What I liked was the bright color and the quick drying time. Also how I didn't need to go over the color to brighten it. However, I am more accustomed

to using wetter techniques for blending, so it was a bit hard for me. Like teaching a left-handed person to write right-handed. 

Just a few more comments.

DO NOT use the same palette for gouache as watercolor. The colors can fool you dry, but gouache should not get into your watercolor paints. 

You can paint gouache over watercolor, but not vice-versa. 

Gouache reconstitutes, so you can spray them to reuse, but not to the extent as watercolor. If you want thick, you need to do it while it is fresh from the tube. They are also more stubborn to rewet.