Golden GAC 400 as a final varnish for acrylic painting.

Hi –

I would be happy to respond to your question about Golden products. First, NEVER use GAC 400 on top of any paint layer or other material. It is far too brittle as a continuous film and should ONLY be used on fabrics and papers made from natural fibers, where it is meant to soak into those materials to help stiffen them. Also, we do NOT recommend GAC 100 as an isolation coat because it is far too prone to foaming. You might be confused as we do often recommend GAC 100 as a barrier or sealer on canvas and wood as a way to prevent either Support Induced Discoloration, where water-soluble impurities from a support can be drawn upwards into a clear or lightly tinted acrylic glaze, medium, or gel, or else to block oil penetration into the canvas when working with oils. For isolation coats, prior to varnishing, we would recommend using a 2:1 mix of Soft Gel Gloss thinned two parts gel to one part water. For more information please consult the following Tech Sheet on the Golden website:

Isolation Coats

Sarah Sands
Senior Technical Specialist
Golden Artist Colors