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Yellow Ogre
10-03-2011, 05:32 PM
I put this together for a lesson today and wanted to share. C&C welcome.

Why Use Gesso?
Preparing a painting surface with gesso serves many purposes:

Gesso smoothes out the painting surface and can hide fabric weave or other surface coarseness when required for fine painting work. Gesso is used to prepare wall surfaces for painting murals. Gesso is MUCH cheaper than paint.
Gesso provides a brilliant white undercoat, especially desirable when painting transparently
Gesso provides a protective layer for the canvas when oil paints are used (not necessary with acrylic paints)
Gesso improves the ability of paint to bond to the canvas (“tooth”) for oil paints. Again, not necessary for acrylic paints).
Gesso can be used to cover an existing painting to allow the canvas to be reused.
What is Acrylic Gesso made of?
Acrylic gesso contains white pigment (titanium dioxide) and finely powdered chalk (calcium carbonate) which create a brilliant white surface, which holds paint well. A fast-drying acrylic medium is used as the glue to hold the pigments together and bonds to the painting surface. Colored liquid gessos (mid-value gray or black) are readily available. Dyes to the gesso prior to application can be added to created a toned ground. Gesso is available in both paste and liquid forms

Supplies List
Drop Cloth / Rags /Smock
Gesso (Paste or Liquid) – in easily re-sealable container
Gesso Flat Brush (1” to 3” depending on size of canvas). Flat house paintbrushes work well.
Trowel or large putty knife
Large Palette knife
Bucket with 6 “ water
Water cup (clean water). Rim wider than brush
Water Mister

How to apply Gesso
Gesso dries very quickly (esp. if working outside on a hot dry day) so working fast and efficiently is essential.
Gesso adheres to clothes and other surfaces permanently. Make sure drop cloths and smocks are in place before beginning.


Lightly dampen the surface and brush bristles with water before applying gesso.
Scoop out enough gesso for a thin coat with the palette knife. Err on the side of less gesso. If too much gesso is used, the gesso will streak, requiring excessive sanding. It is much easier to paint on an additional coat then to sand out streaks. Applied correctly, there is minimal sanding between coats.
Close the gesso container immediate after scooping out gesso. Scrape off excess gesso on the canvas and toss the knife in the water bucket to clean up later.
Immediately spread gesso out to a thin layer with the trowel. Use the trowel first to get a rough coating and then use the brush to cover all the missed spots and smooth out the streaks.
Thin the gesso with water misting if necessary. Don’t apply water after the gesso has gotten tacky, as it will leave pockmarks.
Use long light smooth strokes to avoid streaks. Make final strokes all in one direction. On the next coat, go perpendicular to previous strokes.
Don’t overwork the gesso. If the gesso won’t cover a spot, save it for the next coat.
Don’t forget to do the sides of the panel. Save the sides for last. Hold the canvas panel underneath to do this.
Check for blips or missed spots (especially at the edges)
Leave the canvas or panel face up to help level the gesso and minimize streaks
Toss dirty tools in the water bucket to clean later. Set panel to dry (Typically less than 15 minutes on hot summer day in sun).
When completely dry, sand out any coarse spots with very fine sandpaper (220 grit or higher )
Reapply additional coats as desired. Never apply a second coat before the previous coat is completely dry.
Clean up brushes and tools – don’t leave anything in the water bucket

Gesso Metrics
Are front and sides fully covered?
Coat evenly applied, smooth and adequately streak-free for purpose?
Free of blips?
Adequate coats to hide any undercoat painting or surface blemishes?
Weave of canvas hidden satisfactorily (depends on purpose)?
Right value of tint (If applicable)?

Stacey3352
10-03-2011, 10:54 PM
I may have missed it in your piece but I would have included the clear gesso and its uses as well as heavy gesso for applying texture.
Personally I don't sand mine because I am not doing portraits and find with the way I apply it, slightly different from yours it doesn't streak.
You mentioned adding dyes to gesso to change colour, not sure if you meant acrylic paint or something else. I don't tend to colour my gesso but if I did I would just add some acrylic paint to it.
Good instructional piece, there are often questions here on gesso application.

Einion
10-04-2011, 09:44 AM
Will post more a bit later when I have more time but a couple of quick points:
'gesso' can be removed from clothing quite successfully using an alcohol of some kind, as with acrylic paint itself in some cases;
rollers beat brushes hands down for application of primer.

Einion

Yellow Ogre
10-04-2011, 11:51 AM
Thanks for the pointers! I didn't even know there was clear and heavy body gesso or that alcohol could get the acrylic out.

Stacey, I certainly agree that if you do it right, it doesn't need to be sanded. "Dyes" meant acrylics.
Einion - Like the roller idea. Have to try it on my next batch.