Gouache is a type of Italian water colour paint. It has a colour pigment suspended in water. The particles in gouache paint are much larger than in normal water colour, giving it a hazier look that is unique to gouache. The thickness of your paint can be determined by how much water you add, with less giving your paint a thicker, more reflective look. Gouache can be diluted with water and even soda to give it a different look.
Draw the picture you wish to paint using your pencil on your card stock. Draw it very lightly to avoid pencil lines after you have painted your picture. Be as detailed as possible to avoid fixing design errors during the painting process.
Pick the colours you want for your painting and place a small amount of each gouache paint in paper bowls, one colour per bowl.
Mix your colours with water to create different shades and thickness of gouache. More water creates a thinner, lighter shade while less water creates a thicker, darker shade. Contrast thicker and thinner areas of your painting by adding lighter or thicker coats of gouache. For example, hilly areas can be given texture by applying a thicker, muddier application of gouache. Skies can be given a washed out, hazy look by using thinner coats of gouache.
Paint the darker areas of your painting first. This helps you avoid wasting gouache by letting you create lighter shades after creating darker shades. Plan each new dilution of your gouache carefully to avoid wasting it.
Apply a light amount of water to any mistake on your canvas with a light paper towel to dilute the paint. Use a dry paper towel to remove the paint. Dry the area thoroughly before repainting.
Practice painting with gouache before attempting a major project. Mastering gouache can take some time, so don't get discouraged if your first painting isn't perfect.