Matisse Acrylic Medium MM1 - Drying Retarder 250ml

Matisse Acrylic Medium MM1 - Drying Retarder 250ml. Retarder medium is a slow-drying medium that slows the drying time of acrylic paint. Only the smallest amount is needed, up to 5%. Matisse Retarder does not alter the colour or finish of the paint. Adding over 8% MM1 Drying Retarder will compromise the water fastness 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. However, excess amounts of MM1 Drying Retarder (over 10%) will severely restrict the "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.