Wyland uses these mediums in his painting technique. Wyland mediums are also safe for use in home or studio and carry the AP non-toxic label:
Ecological Acrylic Liquid Glaze Retarder Medium with the colors to provide a transparent yet full bodied glaze, while extending its open time in proportion to the amount of medium added. The liquid glaze retarder medium improves paint flow, adhesion, film flexibility and reduces drag. In addition, this medium provides excellent brushing and leveling qualities and dries to an even, soft gloss.