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Gouache is a paint made by mixing watercolor with white
paint or glue. You’re likely familiar with poster paint, used for
signs and banners, which is a form of gouache.
Watercolor is transparent, which makes it difficult for artists
who use the medium to correct mistakes. Gouache, however,
is opaque enough to cover underlying paint.
Many famous artists, including Picasso, have worked in
gouache.
Look for the term on those tiny cardboard rectangles pasted
on the walls next to paintings in museums and art galleries.
When you see descriptions such as “gouache on canvas” or
“gouache on paper,” smile and know that you’re one of the few
people on earth who actually know what gouache is.