Mediums allow you to alter the characteristics such as consistency, gloss, and drying rate of your acrylic color. They also allow you to paint impasto or with washes. The large variety of acrylic mediums available provide infinite versatility with acrylic colors.
Glossy Medium: Acrylic gloss medium allows you to thin out paint, while giving it a glossy finish. Most manufacturers will advise you not to thin colors with only water. Thinning only with water may make the paint brittle. By adding gloss medium the paint will retain its flexibility.
Matte Medium: Acrylic matte medium is basiclly the same thing as gloss medium with one difference. Matte medium has an additive, or flattening agent, typically silica or a wax emulsion, which creates a flat or dull finish. It is possible to get a semi-gloss finish by mixing equal parts of gloss and matte medium.
Gel Medium:Acrylic Gel medium has the same body or viscosity as most tube colors. When mixed with paint it gives essentially the same effect as Gloss or Matte Medium, but it retains greater textural or impasto possibilities. Using Gel medium also reduces the tint of the color you are working with and increases drying time.
Retarding Medium:Acrylic retarding medium can be sparingly mixed into acrylic paints to slow their drying time. This can allow for subtle effect to be archived only when the drying time is slowed down. However, retarding medium should be used with caution. If too much retarder is used it could produce a paint film that is easily damaged or one that may not dry at all.
Flow Improver:Ideal for when a ":wash-effect": is needed. When used on an absorbent surface it will act as a stain. But when used on a non-absorbent surface, it could cause poor adhesion between the paint and support. Manufacturers recommend testing the product on a scrap or spare support to see the effects before using it on a work that is to be finished.
(Note: do not use a medium as a final varnish; use a true varnish. However, Liquitex makes a Gloss Medium & Varnish which can be used for both purposes.)
