GOLDEN GAC (short for Golden Artist Colors) Specialty Acrylic Polymers are based on 100% acrylic polymer emulsions. The GACs are useful as mediums or modifiers of acrylic paints. GACs can be blended with GOLDEN Acrylic Paints to extend the paint, regulate transparency, create glazes, increase gloss, reduce viscosity or improve adhesion and film integrity. The consistency of the GAC polymers is very fluid and thinner than other GOLDEN Mediums. Since they do not have thickeners added, these polymers will reduce the thickness of most GOLDEN Acrylic Paints. Each GAC product represents a unique polymer that offers certain specific attributes. Therefore, each GAC will have its own unique benefits and applications.

reference: www.goldenpaints.com