In painting, a retarder is a substance, usually a glycol and usually added to water, that is used to slow the drying time of acrylic paints, giving more time for blending or layering highlights. In short, a retarder is an additive used to increase the drying time of acrylic paints.

Use in fine art

Retarders are used to counter the fast drying properties of acrylic paints, making possible the usage of wet-on-wet or other techniques which would otherwise require oil paints. When used correctly, they can keep the paint wet from half an hour extra to a full day's working time. Applying too much retardant, however, can prevent a layer from drying correctly for as long as the retardant is present, causing future damage to the painting unless the affected layer of paint is removed or re-mixed.

In the context of acrylic pour painting, a retarder can be used to prevent paint cracking which usually happens when acrylic paint dries too fast. Introducing a modest quantity of retarder into the pouring medium and paint mix can aid in averting cracks in acrylic pour paintings as they dry, particularly in regions with dry climates that tend to draw moisture from acrylic paint.

Content

They generally contain glycol (such as propylene glycol) or glycerin-based additives.

Home-Made

To create a homemade acrylic retarder, dilute glycerol with water in a 5:1 ratio (water to glycerol) and mix in a few drops of this mixture into the paint. ^[1] This formula is tailored for impasto-style applications.

For fluid acrylic paints used in pouring techniques, dilute vegetable glycerin or glycerol in water in a 1:9 ratio (water to glycerin/glycerol).^[2] Incorporate a small amount of this mixture into the pouring medium for use with your acrylic paints.

References