Gouache is a type of paint, and its greatest advantage is that it is a water color. Aside from that, it is very similar to acrylics. However, the fact that it is a water color makes it different in uses from acrylics. It could also be referred to as concentrated watercolor, which makes it heavier and more opaque.
Step 1. Decide if you need gouache
Note that it comes in small tubes and jars - it is not made to cover large areas with full brush strokes. Then remember that since gouache is a water color it will be damaged by contact with water unless you use lacquer.
Step 2. Start with the primary red, blue, yellow, white and black
Buy these colors that you like and that you will use so often that mixing them yourself would be a struggle (I always buy, on average, a nice light green and purple). I would also suggest adding brown or mustard yellow, as they are useful when trying to "age" a color.
Step 3. Regardless of whether you are going to mix color or not, you should always put gouache on a palette first
Start with a small brush, and check the density of the gouache. Add water, with the dropper, and mix. Always check before using it. If you notice that the tempera is hardening, add some gum arabic and mix well.
Step 4. Especially when working with small, confined areas, clean excess color from the brush
Pay close attention to the base.
Step 5. Wait until the previously colored surface dries before adding more paint on top of it
Water in the new color will reactivate the old gouache - expect the color to melt a little.
Step 6. When you are finished painting, apply the lacquer to any surfaces that could be touched
Step 7. Apply the lacquer very carefully over the color
The lacquer will reactivate the gouache and this will also cause the color to melt. You can trace your steps and reload only a few colors at a time, or be quick and fearless. Remember to always clean the brush as soon as it absorbs the color.
- Always expect the color to melt a little, and don't worry too much about it.
- When you're working on a long project, gouache is perfect because it can be rehydrated and reused multiple times.
- A first layer spray lacquer could help prevent the color from melting, try on a sketch to be sure of your spray technique. Follow the directions on the jar. Several thin layers are probably better than one that is thick and too liquid, which runs and dissolves the color.
- Putting the hairspray on hot, sunny days might help. This way everything dries up faster and damage is reduced.
- The gouache is perfectly cleanable, with water and occasionally soap, from all surfaces. However, it can leave pigments in your fingers, so be careful before touching other things.