Can I paint on wool? If so, what should I add to tempera in order to preserve the wool?

As a starting point, if you have a particular conceptual or other reason for using wool, we don’t want to stop you! But from a conservation perspective, there are several reasons why wool is not traditionally used for making artists’ canvases:

Firstly, wool has short fibres compared with plant fibres such as linen and cotton. The result is a hairy surface that is not smooth to paint on, and the fabric may also be too weak to be applied properly to a stretcher, because of its poor mechanical strength.

Secondly, wool reacts and changes its dimensions when it’s exposed to heat, water and/or friction. It also absorbs damp more easily than other fibres. A fascinating characteristic of wool is that it undergoes an exothermic chemical reaction (it self-heats) when it’s wet! This is one reason why it’s so well-suited to outdoor clothing, because it doesn’t get cold, even in the rain. As a surface to paint on, however, this is less than ideal, since the wool can shrink or swell and may also emit heat. This could cause the paint surface to crack.

If you have a particular reason for using wool, I recommend looking for a fabric that’s smooth and densely woven. Ideally, it should be labelled as ‘Superwash’. This means that it has been treated so it can be washed at 40°C.

If you decide to go ahead with painting on wool, I recommend using a synthetic paint medium such as acrylic, rather than tempera. There are products in natural wool that may react with the egg in tempera paint and even with the linseed oil in oil paint.

Regards from Laura, paintings conservator and Hannah, textile conservator