Gouache is an opaque water-soluble medium that contains pigment, a binder and water. Gouache paints are often used for their vibrancy and fluidity, but they could fade over time.
The amount of time it takes for your gouache paint to fade depends on the pigments used and their fade rate or lightfastness. Paint that is lightfast will not change color with the passage of time. However, some pigments in gouache paints will lighten over time if exposed to sunlight.
It also depends if you’re using gouache for design projects or for fine art. The lightfastness is crucial for fine art. You need to be very careful about it if you plan to sell your art.
Some pigments in gouache paints will lighten over a short time.
While gouache paint does not fade as quickly as watercolors, some pigments in gouache paints will lighten over time. Fugitive pigments would be better used for temporary art that will be photographed and scanned, or kept in closed sketchbooks.
Paint that is lightfast will not fade or change color with the passage of time. Well, not forever, but for decades, even if it’s very difficult to get an accurate information here. Manufacturers will mention ‘extremely lightfast’ without telling you how long it is exactly.
Check the lightfastness of your gouache paint.
The amount of time it takes for your gouache painting to fade depends on the pigments used and their fade rate or lightfastness. Some pigments and some paints fade more quickly than others, so using a pigment that has been shown to be lightfast is important.
Gouache paints use a rating system so that you can be informed about how much they are expected to fade with time. The rating system is based on lightfastness and the amount of time it takes for the paint to fade. It depends on the brands, some are using stars, letters or numbers. Always check on the manufacturer’s website if not available on the tube itself.
You can have more information about gouache tube labels here.
For example, cadmium red lightfastness is rated as “excellent” by ASTM (American Society for Testing and Materials), but yellow ochre lightfastness is rated as “poor”. I’ve personally experienced that Opera Pink will last for less than a year when exposed to direct light.
Protect your gouache paintings.
If you’re willing to exhibit your art and want to protect your finished work from fading, use an artist’s varnish (or other protective sealant) that has UV light absorbers added to it. For more information about how to varnish and protect your gouache painting:
So yes, gouache paints will fade.
When buying gouache paints, you should consider the rating system to determine how much they are expected to fade over time. If there is no rating on the label, then it is recommended that you go with a brand that has been tested and certified by the American Society for Testing and Materials (ASTM) or those who follow their standards.