The Canvas Part II

The glue sizing is dry, so I've started priming the canvas. The primer is lean, and made of very little oil, a lot of pigment, and alkyd resin to speed the drying. Today Titanium white is the most common primer pigment. It's durable, lightfast, and brilliant--reflecting up to 98% of visible light. But Titanium white was only made available to artists in the 20th century. Zinc white enjoyed a brief spot in the limelight in the late 19th century. Zinc is very brittle. Before that Lead Carbonate was used. But unlike the hide glues that are rarely used today, Lead White (or its variants: Flake White, Blanc D'argent, and Cremnitz White) still enjoys wide usage. The reason has to do with its drying properties. Lead is a progressive drier, and a catalyst to the oxidation reaction that causes the "drying" of the paint film. Unlike other colors, lead white dries internally as well as externally. While this is desirable in the paint film, it's actually pretty bad in the priming layers. Because the lead white undergoes a rapid expansion and contraction (caused by the acquisition of oxygen molecules, and the heat generated by chemical bonding) it's best not to paint on a lead primed canvas for at least 6 months. Fortunately, this is something I don't have to worry about with more modern Titanium white and alkyd resin primers.


When priming, it's better to do multiple coats rather than a single thick coat. This leaves the canvas more flexible, and ensures that the pa inting will dry more uniformly. The primer is very sticky, but I've gotten pretty good at keeping it off of my hands and clothes. Each coat of primer has to be scraped on with a knife. It's a slow process. The first coat takes a couple hours to apply and at least a week to dry, but after that things speed up. The whole process is pretty hard on my palette knives. In fact I've broken a few from the pressure. But a while ago I switched to a Holbein knife--the Cadillac of palette knives. They're expensive, but they're hand forged, allegedly by a samurai sword smith. I've found the primer coats applied with this knife to be more even--and I've never broken a knife.

While I'm getting the large canvas ready, I've also built a number of smaller canvases for sketches and studies. Next week, when everything is dry, I'll paint a small head study of my model.