How to protect a gouache painting?

Framing the work behind glass will help. Remember to put a small distance between the glass and the work itself – paintings placed directly against glass are prone to condensation and the growth of mould. A mount between the paper and glass allows just enough circulation to prevent this. To help your work last over time, consider the permanence ratings of the colours you are using. Here’s how the system works:

• AA and A: colours with an AA or A rating, such as Brilliant Yellow and Sky Blue, are not expected to fade.
• B and C: colours with a B or C rating, such as Light Purple (B) and Parma Violet (C), tend to fade over a 10-year period.
• Fugitive: some colours within the C band are known as fugitive, which means transient. These may fade within months.