How to Use Acrylic Underpainting & Then Oils

You must follow certain rules when applying oil paint over acrylic paint.

You can apply acrylic paint or mediums to canvas, wood or other supports as underpainting to oil paints. The inverse is not true, however. Acrylic paints or mediums you apply over an oil-based underpainting will peel or crack as the acrylic paint dries faster than the oil paint. The art rule of "fat over lean" addresses this situation. It states to always put paint with a higher percentage of oil over paint with a lower percentage of oil in order to maintain the integrity of the paint.

Things You'll Need

• Acrylic gesso
• Paintbrushes
• Acrylic paint or medium
• Oil paints

Instructions

1. Apply two to three coats of acrylic gesso to the canvas with a wide brush. Allow to dry to the touch. This may take up to an hour.

2. Use a brush or painting knife to apply the underpainting. This may be one layer of acrylic paint, several layers of acrylic paint, or acrylic medium. Allow to dry between coats and after the final coat of the underpainting. Drying may take 2-4 hours for thick coats of medium or layered paint.

3. Clean all of your acrylic brushes with water and soap to avoid mixing the acrylic paint with oils.

4. Paint as usual with oils. As the top layers of your painting, the oil paints will contact the air, oxidize and cure normally.

Tips & Warnings

• The stiffer your painting surface, the better adhesion your oil painting will have. Painting oils over acrylic painting on a flexible surface can lead to unstable paint.

References

• ArtistsNetwork: Tip File: Fat-Over-Lean Rule