Friday, March 7, 2014

What the Heck Is Gesso? [feedly]




What the Heck Is Gesso?
// The Artist's Life

Gesso is one of those words that seems to stop beginners in their tracks. It leaves many wondering how to use with acrylics or if you even need to use it in an acrylic painting.

Historically, it is for oil painting and was traditionally used to prepare or prime a surface so oil paint would adhere to it. It is made from a combination of paint pigment, chalk, and binder. Gesso would protect the canvas fibers, provide a nice surface to work onto and give a little flexibility so the canvas wouldn't crack if it was rolled.

Acrylic gesso. Photo by Will Kemp.
Acrylic gesso. Photo by Will Kemp.
Traditional oil gesso (pronounced 'jesso') could be described as more of a 'glue gesso' as it contains:

-Animal glue binder - usually rabbit-skin glue

-Chalk

-White pigment

The oil gesso creates a surface that is both absorbent (this comes from the chalk) and has a 'tooth' (texture) that allows the paint to grab onto the canvas.

So what is acrylic gesso?

Modern acrylic painting gesso is a combination of:

-Acrylic polymer medium (binder)

-Calcium carbonate (chalk)

-A pigment (usually Titanium white)

-Chemicals that ensure flexibility, and long archival life.

Note how the acrylic gesso doesn't contain glue. Acrylic paints are non-corrosive and stable overtime, so you don't need to worry about the paint damaging the canvas, and therefore, you don't need the glue in the mix. Remember, traditional oil 'glue' gesso soaks into the canvas fibers and helps to protect them from the corrosive nature of oils, over time.

Why do I need to use a gesso primer for acrylic painting?

Technically you don't. It provides you with a nice, slightly more absorbent surface to work onto, especially if your working on board or raw canvas but for a pre-primed canvas it's unnecessary. Don't forget your pre-primed canvas from the art store already has a layer of gesso on it. Gesso is the same as a primer, as in 'pre-primed canvas.'

But here's a pro tip for painting with acrylics and gesso: you can also add other paint colors to your gesso to give you a toned surface to work onto.

So grab your paints, you're ready to go! You can also have a look at how I apply acrylic gesso to a canvas.

--Will

 



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