Retarder Medium is an additive to extend the ‘open’ or drying time of Chroma’s Jo Sonja Artists’ Colors or Mediums. It may be used as both a painting medium and for various techniques such as antiquing.
Antiquing: • A barrier coat of Clear Glaze Medium is recommended before antiquing, then thin paint with Retarder using a ratio determined by the strength of color desired. Begin with 1 part paint to 1 part Retarder. • Apply over painted surfaces and then wipe off to produce an aged effect. For additional open time, apply a light coat of Retarder directly to the surface. Use a small amount of Retarder on cloth to remove excess. • Allow 48 hours drying time before varnishing. An extended dry and cure time should be allowed and varies due to humidity and climatic conditions or if an excessive amount of Retarder has been used. A hair dryer may be used to speed surface drying. • A coat of Clear Glaze Medium is recommended prior to application of varnish.