Matisse MM1 Drying Retarder

What is acrylic retarder?

Retarder medium is a slow-drying medium that slows the drying time of acrylic paint. Only a tiny amount is needed, up to 5%. It does not alter the colour or finish of the paint. The length of the extended drying time is affected by temperature and humidity.

How much acrylic retarder should you use? 

Adding over 8% MM1 Drying Retarder will compromise the waterfastness of the dried paint by slowing the acrylic cross-linking. Therefore, although the paint may appear dry, it can be re-wet with a wet brush or cloth.

What happens if you add too much Acrylic Retarder?

Drying Retarder will slow the evaporation of water from the paint. However, excess amounts of MM1 Drying Retarder (over 10%) will severely restrict "cross-linking" of the acrylic. Therefore, even though the paint may look dry (and indeed, all the water will have gone from the colour), it will not have "cross-linked" or "cured", so it can be re-wet, i.e. with a wet brush or cloth.But if you take a wet rag, it will come straight off because there's been no bonding. It hasn't stuck together. It hasn't adhered; it hasn't glued. So it's going to come straight off. It might take several months for that drying retarder to evaporate out eventually.

Can acrylic retarder medium be used with other mediums and additives?

Yes. Acrylic retarder medium can be combined with other Matisse mediums and additives.