Smooth and Smoother
Surface Texture and Panel Performance

In over a decade of making art panels and two decades of selling art supplies, we've learned a few things about artists' preferences. For one, most every artist who is looking for an art panel thinks it should be as smooth as possible. For another, most artists are dissatisfied with most of the painting panels that they've tried. Well, there's a connection.

Most primed art panels have very low absorbancy, whether they are primed with an oil or oil-based primer, acrylic gesso, or a "clay" coating (an acrylic emulsion with clay-derived filler particles). (Hand made "true gesso" panels, made with hide glue or casein, are an exception. The pigment particles in these gessoes are simply mixed into the binder, rather than ground into it using a mill. This results in poorly wetted "clumps" of particles which draw paints into the dried gesso by capillary action.)

		The combination of a smooth surface and low absorbancy results in two problems: poor brush handling and paint application difficulties for the artist, and poor adhesion of your paint to the primer. On a too-smooth, low absorbancy surface, brush strokes tend to leave white streaks,
rather than depositing the controlled applications of paint which an artist needs. Painters describe the surfaces as feeling "slippery" or "slick". Brush control becomes difficult, and careful paint application can be frustrating. Painters often compare it to "painting on glass".

A well prepared surface, on the other hand, should be an aid to paint handling. A good painting surface should help the artist achieve the most nuanced paint application, accepting paint from the brush in a carefully controlled interplay of brush and surface.

If a gesso or primer has low absorbancy – which it should – then it needs to have a slight micro-texture in order to provide optimal receptivity for your paint. A little bit of friction is needed to "grab" the paint, pull it off your brush, and hold it in the places that you intended it to go. On a too-smooth surface, your brush slips across the surface without leaving paint behind where you intended. Too avoid this, the artist is forced to overcompensate by brushing extra slowly, applying extra pressure, "twirling" the brush, etc.

Prior to the introduction of steel-roller mills for preparing pigments and paints, the usual particle size of pigments and fillers in primer coatings was much larger than it is today; this gave primers the needed micro-texture for proper paint handling and adhesion. But largely due to steel-roller milling, few manufacturers today include large enough particles in their coatings; to do so demands more care and is more expensive. Frankly, we doubt that most manufacturers even know that they should. What's more, uniformly applying a coating with a very fine texture is more difficult than simply polishing a coating to a very smooth finish. Hence the proliferation of ultra-smooth polymer gessoes and slick "clay coated" bords.

Finally, some painters assume that it takes a glassy smooth primed surface to achieve a glassy smooth paint finish. But on a surface with a very fine texture and closely spaced particles, the viscosity of artists paints is usually sufficient for the surface tension of the paint to span the gaps between the particles without sagging into the troughs, allowing artists to achieve very glossy surfaces when desired.