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This article is a condensed excerpt from the book Egg Tempera Painting: A Comprehensive Guideby Koo Schadler. For a more in depth-discussion of true gesso panels, please refer the book, available at www.kooschadler.com.
Four to six days from start to finish are required to create a true gesso panel using a homemade gesso recipe. Only one (or two) of these days is a full day. The other days involve anywhere from a few minutes to an hour of work.
1. Panel: This gesso recipe yields enough gesso to cover both the front and back of a 2×2-foot square panel with six to eight layers of gesso. Use either a solid wood, plywood, or hardboard panel. Solid wood panels must be well aged to prevent shrinkage. Plywood comes in various grades. A high quality, cabinet grade, birch plywood is best. Hardboard is more commonly referred to as “Masonite” or “MDF.” Untempered hardboard is preferred but not requisite.
To prepare the panel, first roughly sand the front and back to create a little “tooth.” Then wipe both sides with denatured alcohol. Next, use a flat bristle brush to apply a coat of warm rabbit skin glue as a primer to both sides. (For instructions on preparing rabbit skin glue see “Making Gesso,” below.) When both sides are dry, sand them lightly.
At this point a layer of cloth should be applied to solid wood and plywood panels to prevent the wood grain from telegraphing through the gesso. This step is not necessary on hardboard panels because they do not have grain. A fine weave linen or muslin may be used. Use rabbit skin glue to attach the cloth. Gesso is then applied to the cloth-covered panels in the same manner as to plain hardboard, as described below.
EQUIPMENT NEEDED TO MAKE GESSO
- A diet or postal scale for measuring
- One quart measuring cup
- Double boiler
- Extra pot
- Large spoon
- Mesh strainer
- 1- to 2-inch flat bristle brush
INGREDIENTS FOR GESSO
- Rabbit skin glue in dry, granular form – 1½ ounces by weight (Use a scale to measure.) One-half ounce is for priming your panel. One ounce is for making gesso. Other animal glues (hide glue, gelatin) may be used, but rabbit skin glue is best.
- Inert White Substance – 3 cups by volume (Use a measuring cup to measure.) There are several types of inert white substances; all are either a form of gypsum or chalk. My preference is marble dust, a type of chalk.
- Water – For the gesso, distilled water is recommended but not requisite.
- Titanium White Powdered Pigment – 2 ounces; This is an optional ingredient. It increases the opacity and reflectivity of the ground, but it is not requisite.
Note: Recommended suppliers are listed at the end of the article.
HOMEMADE GESSO RECIPE AND APPLICATION INSTRUCTIONS
Day One: Put ½ ounce of rabbit skin glue and 8 ounces (1 cup) water in the upper pot of a double boiler and stir. This glue will be used to prime your panel. Put another 1 ounce of glue and 16 ounces (2 cups) water in a second container and stir. This will be used to make gesso. The glues will absorb water, soften and expand. This will take four to eight hours, depending on the fineness of the glue granules.
Don’t let hydrated glue go unrefrigerated for more than a day. Animal hide glue is an organic product. Once wet, it will age and eventually go bad. Do not use old, stinky or moldy glue.
Day Two: Fill the lower pot of a double boiler with water and place it on a burner until the water is hot. Remove the pot from the burner and then place within it the upper pot with the mix of ½-ounce rabbit skin glue and water. Stir occasionally. The heated water in the lower double boiler pot, removed from the stove, will be sufficiently warm to melt the glue.
Never heat glue or gesso directly over a flame. Too much heat will destroy the glue. When the glue is liquefied, pour it through a fine mesh strainer. It is ready to apply as a primer to your panels, as described above in “To Prepare your Panel.”
Day Three to Four: Allow yourself 6-8 hours to do the following. Warm the second mix of 1 ounce glue and 16 ounces water in the double boiler. Heat the mix until just warmed, so you can comfortably put your finger into it. Working with glue that is too hot can result in air bubbles, as well as ruin the glue.
Next take 3 cups of inert white substance (I prefer marble dust) and slowly sift it into the warm glue. I use a mesh strainer to add the marble dust so that the powder falls into the glue like a light snowfall. If your powder is added too quickly or is stirred too vigorously air bubbles can develop, so work slowly and attentively.
To increase the reflectivity and opacity of the gesso, substitute up to 10 percent of your inert white substance with titanium white pigment. Adding too much titanium will create a soft gesso, so don’t add more than 10 percent. This step is optional.
When all of your inert white substance has been added, gently stir the gesso once or twice. It should have an approximate consistency of light cream. Slowly pour the mixture through a fine mesh strainer into another pot to remove blobs. Clean out the upper double-boiler pot and, once again, gently strain the mixture back into the cleaned pot. Your gesso is ready to be applied.
At this point, if you have the time, let the gesso sit overnight. Sitting allows air bubbles to dissipate and the inert white substance to be more fully absorbed by the glue. The result is a smoother gesso. The gesso must be refrigerated while it sits, or the glue may go bad. Gesso takes on the consistency of very hard Jell-O when cool but redissolves readily when warmed. Carefully reheat the gesso in your double boiler until the gesso has liquefied. Once this happens, the gesso is ready to be applied.
Use a flat, 1- to 2-inch bristle brush to apply the gesso. Brush the first coat onto the panel, and then rub it vigorously into the surface with your fingertips. The result is a thin, irregular, transparent layer of gesso. It should dry fairly quickly (10 minutes) depending on drying conditions. Do not try to accelerate drying by placing a panel in strong sun or near a fan or heat source—the gesso could crack.
Apply subsequent coats of gesso with the brush only. With each new layer, the panel is turned so that the strokes are at right angles to the previous coat. As well as you can, smooth out the surface with the brush as you go until the gesso starts to set and the brush begins to drag. When you can gently touch the surface with your fingertips without lifting gesso, it’s time for the next coat. Do not delay too long between coats, as that may prevent proper adhesion between layers. Many coats of gesso are necessary to achieve an opaque ground. I recommend five coats minimum, but eight to nine coats are preferable.
If foreign particles or brush hairs get stuck in the gesso, do a light sanding between coats to lift them out. Do not bother with a heavy sanding between coats—save that for the end. Do not cut corners by applying just one or two really thick coats, as the gesso may develop fissures or air bubbles. To prevent warping, it is best to apply gesso to both sides of a panel. Once the panel is gessoed, let it sit for a few days to fully dry before sanding.
SANDING A GESSO PANEL
- Sandpaper – 1 sheet each 120, 180, 220, and 400 to 600 grit
- Sanding block
- Small bowl of water
- Denatured alcohol (available at hardware stores)
Always wear a respirator when sanding. The dust is an irritant to lungs, and some forms of chalk contain silica, which is harmful.
Use a sanding block. Begin sanding with 120 grit. Bear down fairly hard on the panel until you’ve removed brushstrokes in the gesso. Study your panel in raking light to clearly see the surface. Once brushstrokes are no longer evident and only sanding marks from the sandpaper itself remain, move onto the next grit sandpaper. Work with an increasingly light touch and increasingly fine sandpaper (up to 220 grit) until no marks of any sort remain when you look at the surface in raking light. Sand the panel’s edges as well, giving them a chamfer (45-degree angle) so they do not chip.
Next, dip your fingers in clean water and rub the surface of the panel. This loosens and redistributes the gesso, smoothing it further. Initially your fingers will move readily across the moistened surface, but then start to drag a bit as the gesso begins to dry. Keep rubbing and smoothing out the gesso, working your way across the panel, until the surface is smooth and dry.
Let the panel sit for 10 to 20 minutes to fully dry. Then do one final, gentle sanding using 400 to 600 grit sandpaper. This last sanding can create a surface like an ivory piano key.
Finally, before you begin a painting, it’s a good idea to wipe a panel with a cloth dipped in denatured alcohol. This removes greasy fingerprints or other unknown contaminants that could make the panel unreceptive to paint.
And now, onto the best part—painting!
- Kremer Pigments: www.kremer-pigments.com; 212-219-2394
- Natural Pigments: www.naturalpigments.com; 888-361-5900
- Sinopia: www.sinopia.com; 415-824-3180.
© Koo Schadler 2012; For more information or to order Koo’s book Egg Tempera Painting: A Comprehensive Guide, visit www.kooschadler.com.
You may be interested in these other resources:
- Stretching and Priming Your Canvas (available at www.northlightshop.com); In this DVD, Larry Wither demonstrates step by step the proper procedures for assembling, stretching and priming artist canvas.
- “Getting Started in Egg Tempera”- Brushing Up article in the April 2013 issue of Magazine