Retarder Medium is an additive that extends the ‘open’ or drying time of Jo Sonja Matte Flow Acrylic and Mediums. It serves as both a painting medium and a tool for various techniques such as antiquing.
 
Directions:
As a Painting Medium: Lightly moisten the brush with Retarder before picking up paint. This will extend the working or ‘open’ time during application.
For Extended Working Time: Apply Retarder directly to a prepared surface using a mop brush to ensure even coverage.
Mixing with Paint: Begin mixing Retarder into palette colours with a starting ratio of approximately 1 part Retarder to 3 parts paint. Adjust the ratio as needed for your technique. Adding more Retarder will increase the transparency of the colour.
 
Antiquing:
Preparation: Apply a barrier coat of Clear Glaze Medium before starting the antiquing process.
Application: Thin the paint with Retarder, starting with a ratio of 1 part paint to 1 part Retarder. Apply over painted surfaces and wipe off to produce an aged effect. For additional open time, apply a light coat of Retarder directly to the surface.
Cleanup: Use a small amount of Retarder on a cloth to remove any excess paint.
Drying and Curing:
Allow 48 hours of drying time before varnishing. Extended drying and curing time may be necessary depending on humidity and climate conditions or if an excessive amount of Retarder is used. A hairdryer can be used to speed up surface drying.
 
Before Varnishing:
Applying a coat of Clear Glaze Medium before varnishing is recommended to ensure the best finish.
 
Coverage and Safety:
Coverage: Approximately 1 ml covers 251 sq cm, 1 oz covers about 8 sq ft.
Cleanup and Safety: The product is water-based, non-toxic, conforms to ASTM D 4236, and can be cleaned up with mild soap and cool water. Safe to dry with a hairdryer.