Creative Techniques: What Are Grounds?
A few definitions before we begin as it is often confusing to figure out the difference between primers, sizing, and grounds and how they may all interrelate.
Sizings are materials such as glue or gelatin which are used to prepare canvasses prior to priming. Primers, by definition, are substances that provide a suitable prepared surface for painting in terms of adhesion, color and isolates the paint film from the support (the structure on which the painting sits such as wood or paper, etc…). The sizing can decrease the absorbency of a paper which is why printmaking papers are so absorbent, they have no or relatively little sizing. A ground is a surface on which color is applied (usually a coating).
Primers and Sizing can be considered the same thing and are there to help with adhesion, penetration and bonding to the substrate or support. Sizing on canvas, for example, is there for stiffening, blocking and preventing penetration and has nothing to do with film property.
The main functions of a ground are to protect or isolate your surface from potential impurities or ingredients you may put on your surface. Secondly, grounds help with surface adhesion. Some grounds provide a tooth or absorbency that allows the surface to accept or cover paint. Grounds can enhance the colors of the paints used as they provide a “white reflective surface”. Finally, there are so many grounds around that it is also useful to speak of them in terms of usage. What effect or type of surface are you looking to recreate? Are you looking to have good surface adhesion but be able to see the underlying coat? Are you wanting a colored or pure white opaque painting surface? A more translucent ground perhaps? Perhaps you are looking for products that allow you to create decorative or textural effects? Perhaps a specialty ground for drawing or transferring digital imagery?
Most artist know about gesso. Golden’s black or white Gesso, like most gessos, promotes paint adhesion and gives your supports some “tooth”. When thinned down and applied in thin layers Golden’s gesso will allow good adhesion to textured surfaces.
Some artists use cheap household paint as primers. This can be problematic if you are intending to use transparent glazing techniques using the white of the ground to create your painting. Most of these water-based emulsion paints are made to only withstand 10 years of life. They will eventually leave a dull, yellowing, brittle paint film and disappointed customers. If you use more of an opaque painting technique and a rigid support you can probably get away with doing this.
GOLDEN Gesso is a flexible liquid ground that seals, protects, and gives “tooth” to substrates, which promotes paint adhesion. It is formulated to accept a wide variety of media on many commonly used painting surfaces. It comes ready-to-use, but can be mixed with water for thinner applications. Two coats are usually recommended but additional coats provide an even smoother surface. For instance, a hard-edged painter may want to create such a surface then wet sand to reduce dust production.
GOLDEN Gesso can be brush, roller, trowel or spray-applied. When applied in thin layers, GOLDEN Gesso will conform to a variety of textured surfaces. When diluting with water, a maximum dilution of 25% is usually recommended to prevent the possibility of cracking. If you work with an airbrush and require a thinner gesso application, you can thin the Gesso by blending it with Golden’s Airbrush Medium 1:1 . You can also mix acrylics with color in order to create a multitude of colored surfaces.
Another great product that closely resembles Gesso are the High Load Acrylics. These High Load Acrylics possess a high pigment load and have a luxurious velvety feel. The one drawback is that they are easily marrable . Both gesso and High Loads should be applied in thin layers. Matte Fluid Acrylics are the best option after the High Loads.
Oil Paints can be applied over acrylic Gesso but to control and lessen the penetration of linseed oil into the support fibers, a two coat-application of GAC 100 or GAC 700 is recommended before applying Gesso. If you need to stiffen the support before you apply the Gesso, GAC 400 can be applied first.
The wonderful world of acrylic grounds also allows you to increase flexibility, lower tooth, alter texture, absorbency and viscosity so that you can recreate the ground you are searching for. For instance, adding GOLDEN GAC 100 (a thin, multi-purpose specialty acrylic medium) will reduce viscosity (product thickness). The film that is created is thinner, stronger and more flexible. Adding a gel or a gel with inclusions (with “stuff” in it) such as Coarse Pumice or Coarse Molding Paste will alter the thickness and feel of a gesso, increase flexibility, increase or lower tooth and absorbency in certain instances. Adding more or less of a product will consequently alter the Gesso or other grounds accordingly. Understanding the workings of gels, mediums, and acrylic products in general allows you to custom design your surface. Like anything else, you need to test the mixtures.
*Image courtesy of: www.goldenpaints.comBack