The Priming Layer
Updated: Feb 25, 2021
The priming layer or ground a painting is placed upon has gotten a lot of attention in recent years. Since the priming layer serves as a foundation for a work of art it deserves to have a critical role in the successful completion of a sound, integrated artwork.
I believe that most of you know the difference between traditional gesso and the materials we use today for priming. However, for those who do not, gesso is the traditional burnt gypsum, (plaster of Paris) and animal hide glue ground that is applied to wood panels to create a painting surface. It creates a wonderful coating that accepts paint well. It is very brittle and hence, the need for a thick wooden support is mandatory. Traditional gesso cannot be applied to a stretched canvas in the thickness needed to stop the penetration of oil paint. (More on this later.) Even a fairly thin layer would be susceptible to cracking and flaking.
Today, tradition painters can still use gesso. However, with the advent of acrylic paints, a modern primer has become established. Acrylic dispersion primers that many refer to as acrylic gesso, have become the choice for many artists who prepare a suitable grounds for painting with oils and acrylics. While some grate at the term “acrylic gesso,” it is not a problem if an artist realizes that they are only borrowing the name from the traditional gypsum and glue ground layer.
Acrylic dispersion primers are formulated to provide a surface that accepts paint, but provides protection for the support. This is an important concept. We know that when oil paint makes contact with a woven support like cotton or linen, the oil in the paint will oxidize the fiber and cause premature deterioration. This is important since paint alone cannot provide the needed structural support to hold a painting together.
In addition, painters and manufacturers of grounds came to realize that acrylic dispersion grounds have qualities that allow material to move fairly freely through the surface, much more than anyone intended. It was reported that when acrylic grounds were applied to hardboard, material leached from the hardboard, migrated through the ground and appeared as an overall discoloration. Water soluble materials in the hardboard, dissolved by the water that makes up a sizable portion of any acrylic dispersion ground, pulled these materials out of the wood into the ground. Realizing that grounds were a conduit for movement of material in either direction, the manufacturers and artists concluded that a sealing or sizing layer needed to be placed on hardboard, or any other support, to stop the potential for oil or products in the support from migrating. This translated into a variety of sizing products and manufacturers suggesting two or more coats of primer.
Acrylic dispersion grounds provide a surface that maintains good mechanical adhesion properties and protection of the support if used as directed. Of course, an appropriate sizing layer gives added protection with a higher level of assurance that material will not migrate from the oil paint into the canvas support.
Some artist ask, why not just make acrylic gesso less porous? Since mechanical adhesion of the initial layer of paint is important, a compromise is reached by providing artists with products that are absorbent within a wide range of painting styles. This absorbency is manifest when artists notice that a freshly dried oil paints layer looks powdery, loosing nearly all of its gloss. This dry surface is ideal for adhesion of subsequent paint layers. However, if this powdery looking layer is the final one, an artist must decide the level of gloss desired and use a varnish that will saturate the mat appearance of the colors.
Some oil painters use canvas prepared with oil grounds. Traditionally, these are made of lead white and linseed oil applied to a rabbit skin glue prepared canvas. Since it is known that all hide glues like the highly refined rabbit skin glue absorb and loose moisture from the air that promotes cracking, a number of moisture impervious sizes such as polyvinyl acetate may be substituted. Alkyd grounds are also used by painters. The preparation is the same as that used for oil grounds. Alkyds provide a strong and moderately flexible alternative to white lead grounds. They are also more environmentally friendly, since titanium white rather than lead is used as a colorant.
Today’s materials made by reputable art manufacturers provide an outstanding priming layer that is made with materials that provide excellent longevity. Artists who succumb to using acrylic house paints should realize that these materials are not made for the intended purpose of providing good mechanical adhesion and protection of the support. House paints are made from basic ingredients that have short-term life spans.
The debate will go on for some time as to which grounds provide the best working properties. (Aside from students and artists clearly making works as practice exercises) When artists comment on primers, many say that any old cheap paint will do. However, I reply that if you are selling your work (in some cases, for fairly substantial sums of money) from an aesthetic point of view, don’t you want your image to sustain its appearance over time? From an economic integrity viewpoint: Don’t you want to know that what you make will hold its value and not prematurely deteriorate? From a purely practical view: A well made support or poor one – how do you know before you start that this will not be one of your greatest paintings? It would be ashamed to create a masterpiece on a substandard primed canvas.
The Syntax of Color
Original Grammar of Color Essay
Vol: 1 No. 5 (Published 03-23-05)