Medium Density Overlay, MDO

Found in hardware stores and lumber yards, this sign painter’s material provides proven stability. Large and/or thin panels should be cradled or braced to mitigate warping.

A ground or barrier coating is not required when working on MDO with acrylics, oils, watercolors, or dry media.

When painting with an acrylic paint, medium, gesso, or ground, two or more initial coats of Gloss Medium can be applied to reduce Support Induced Discoloration (SID).

Any of our Gesso & Grounds, Gels & Pastes, and most of our Fluid Mediums can be applied to alter the absorbency, durability, or texture of the surface.

For watercolors, we typically recommend applying Gesso followed by one of our three QoR Watercolor Grounds for a bright white absorptive surface.

For dry media like PanPastel, we recommend applying a textured ground or paste for improved tooth.

If your MDO panel will be displayed outdoors, prime the surface with an exterior-grade primer suitable for waterborne topcoats and seal the vulnerable edges with additional primer and/or exterior-grade filler. A final varnish or clear topcoat is recommended for greatest durability. See our articles below for more information.

Video: Support Induced Discoloration (SID)

Article: Medium Density Overlay, Preparing Panels for a Life Outdoors, Understanding Wood Supports for Art

Tech Page: Surface Preparation