Making Chalk Grounds is probably one of the most difficult processes to learn, because so many things can affect the outcome of a chalk ground (temperature, humidity, type of chalk, type of glue, etc.) While there are many approaches to making a chalk grounds, here is a simple approach that can be altered as needed. The first thing to consider is that any chalk ground has to be applied onto a rigid surface. Chalk Grounds have a tendancy to be brittle and therefore would crack and separate from a flexible ground. The best rigid surface would be a wooden panel. In order to avoid uneven moisture absorption by the wood, the panel has to first be sized front back and side with a natural glue size (rabbit or hide glue).
Preparing Glue Size
Usually two layers are enough to seal the wood effectively.
At this point it is advisable to adhere a piece of fabric (thin muslin sheeting) to the panel to help stabilize the ground and to protect it from joints in the panel that might show in the gesso.
The fabric can be adhered to the panel by painting down a thin layer of glue-solution to the front of the panel and soaking the fabric in the glue solution. Once the fabric is stretched over the front of the panel, allow the glue to dry thoroughly before trimming off the excess fabric from the edges. The left over glue-size then gets used for the chalk ground.
Chalk Grounds: Ingredients
Chalk Grounds: Directions
Note: When applying layers of ground, brushstrokes should be applied in one direction for every coat.
Reapply subsequent layers in a perpendicular direction to the previous application.
Whites should be chosen according to desired brightness and opacity. Titanium white is very bright and covers in about two layers, whereas zinc white has an off white hue and requires four to five layers to cover. To make colored grounds, try using some of our earth pigments, to achieve traditional venetian red or ocher tinted grounds. Simply substitute the white pigment proportion from the above recipe.
For Oil based primers there really aren't any specific guidelines to follow, mostly because there is a large variety of ingredients that can be used. As a colorant all types of white pigment can be used: lead white, zinc white and titanium white. As a filler both chalks and marble dusts can be used. The most important thing to remember is that the canvas that is going to be primed, needs to be sized first. This can be achieved with a solution of Rabbit Skin Glue.
For Rabbit Skin Glue size, soak one part of Rabbit Skin Glue grains in twelve parts of water overnight. Heat the mixture in a double boiler and apply warm to a stretched canvas. Make sure the Rabbit Skin Glue soaks into the fibers, sometimes the solution has a tendency to sit on top of the canvas. Repeat application.
Once the Rabbit Skin Glue has dried, it is ready to be primed. To make the oil primer, take any desired measure of white pigment and place it onto a clean non-porous surface. Then with the aid of a palette knife or spatula, work a small amount of cold pressed linseed oil into the pigment. If the paste becomes too runny, that's ok and actually desirable. At this point, add small amounts of either marble dust or chalk to the mixture and work it into the color paste. Once the mixture has been worked up into a thick paste, it is ready to be used as a primer. For application purposes the mixture can be thinned to any desired consistency, by adding a small amount of mineral spirits or turpentine. The paste can be thinned slightly for application with a spatula or it can reduced to a thin solution for brush application.