How To Make Gesso

Traditional Gesso

Traditional Gesso is the Foundation for so many aspects of art, from Traditional Water Gilding of Frames, Furniture, and Architectural Detail to Egg Tempera Gilded Panel Paintings, Pastiglia, and Iconography.

I first learned to make gesso over 30 years ago. It was at a time when not too many people were giving away their secrets. But there those who were leading the way, William Adair, Peter Sepp, Adair Chambers, Frances (Binnington) Federer, Stanley Robertson, Grace Baggot….

I started with a formula for gesso which was a one-step approach , gently building a mountain of calcium carbonate in a 10% solution of rabbit skin glue and water, spooning in the calcium carbonate (also known as Whiting) until it started to fall down along the sides of this mountain of Whiting. That was the sign that you reached the right ratio between Whiting, Glue, and Water.

Grace later lead me to her gesso recipe which she learned in England, an Old World formula that was based on a hard and soft gesso approach where the soft gesso contains more whiting than the hard gesso, building a pyramid of strength. I later came across this same recipe in the Publication Gilded Wood Conservation and History edited by Deborah Bigelow whose class on Toning Gilding I was fortunate to attend some years ago in NY. The gesso recipe was presented in the Paper Some Mechanical and Physical Properties of Gilding Gesso by Marion F. Mecklenburg among a Collection of Papers published in Gilded Wood in 1991 submitting that this particular recipe was shown to have the greatest strength and responsiveness in the analysis conducted.

Meanwhile, one more switch I made was to the Metric System for its greater precision in weighing by grams compared to the American system of cups and ounces and this approach has served me well throughout my years of gilding and remains the recipe I teach today.

Interlaggio: The Use of Fabric Under Gesso

I have found that when water gilding large flat surfaces, the gesso can have a tendency to develop hairline cracks. Fabric has been used for centuries for reinforcement of gesso and plaster surfaces and can help minimize or prevent these cracks from occurring. During the first step of water gilding - applying hot size (glue) to the wood surface - I like to size the front (and back if applicable) and let it dry 24 hours. The next day saturate the fabric with very warm size in a bowl and gently wring it out slightly. Lay the linen on top of the flat surface or panel and be sure the linen lies flat across the wood, smoothing out the wrinkles with your fingers. After the glue dries after 24 hours, trim any loose ends of the fabric.

Inspect the dried linen very carefully to see if there are any dried air pockets under the fabric. If there are, slice a small cut into the air bubble with a razor blade or an Exacto Knife and wet the area with saliva or a little warm rabbit skin glue to adhere the fabric around the air pocket to the surface to insure adhesion. This is an important aspect of successfully applying the fabric to the panel as air pockets will prohibit proper adhesion of the gilding to the wood surface.

An alternatice to fabric is a thin Japanese Paper one being Sekishu which I’ve used effectively over the mitres of picture frames when water gilding as the mitre can cause the gesso to crack through the expansion and contraction of the wood. This is also an effective technique used as times in gold leaf restoration.

Historically, the use of fabric between the sized surface and the gesso has also been used on metal before gilding. There is some evidence of this from early Egyptian gilding although it's a method most suitable to porous wood. The fabric will help the gesso to adhere to a non-porous surface but it will likely not be as long lasting as when done on wood.

Gesso For Traditional Water Gilding

Traditional Gesso is the combination of a protein binder (Rabbit Skin Glue, or simply RSG), distilled water, and either Calcium Sulphate or Calcium Carbonate - also known as whiting, or chalk - as a filler or bulking agent. It is not to be confused with the acrylic or oil-based gessos for canvases.

The traditional gesso recipe used in water gilding performs two functions: filling the grain of the wood and providing a smooth, hard surface that allows water gilded gold leaf to be burnished to a brilliant lustre, assisted by the soft cushion of clay bole applied to the prepared gesso.

The preparation of all of the recipes I use in water gilding are quite precise including that used to make gesso. One very important consideration is the strength of the RSG formula which is a 10% solution: 9 parts water to 1 part dry RSG, either in pebble or granular form. If the RSG solution is prepared too strong there is risk in developing crack mechanisms in the gesso layer. Likewise, if the RSG solution is too weak, one faces the possibility of delamination of gesso from the wood substrate.

Numerous layers of warm gesso are hand-applied or sprayed onto the wood surface. Each layer is allowed to dry only long enough so the application of the next layer does not disturb the previous layer. Anywhere from 5-20 coats may be applied, depending in part upon the object and the desired effect. The intent, which dates back to the early Egyptians, is that the wood appear as solid gold, an effect created largely by the use of gesso as a ground for gilding.

There are a variety of approaches used throughout the world in the successful preparation of gesso and although recipes and methods may seem at first glance to differ, the basic principles of glue strength and the ratios of RSG to Whiting are quite similar when analyzed. Logically, they would ultimately need to be since the relationship between the binder and the particles of calcium carbonate are subject to the same physical principles.

As an overview of preparing traditional gesso, its function is in filling the grain of wood and allowing the gold leaf to be burnished. It is also of great importance to understand the relationship between the strength of the binder (usually RSG - rabbit skin glue) and its relationship to the filler (whiting - calcium carbonate, or calcium sulphate). If the glue strength goes much beyond the 10% solution, the possibility of crack mechanisms in the gesso increases; likewise, if the glue strength is too weak, gesso delamination from the wood surface could occur.

This two-part Hard and Soft gesso recipe may be found among other gilding recipes for Download on the Class Materials and Recipes page of the gildingstudio.com website.

Applying Gesso

A raw wood surface is first coated with a thin coat of very warm 10% rabbit skin glue over all exposed areas to seal the surface and provide a foundation for the following coats of gesso. The Sized wood is allowed to dry for at least 24 hours which also allows the wood to return to a state of equilibrium. Gilded Panels are also given the extra treatment of a layer of thin linen or silk applied to the top surface during this initial Sizing stage which helps guard against crack mechanisms appearing in the gesso.

Once the proper gesso mixture has been prepared a sufficient number of coats are applied which in my own Practice is generally 14 coats - 4 Hard and 10 Soft. This is my general approach for flat surfaces such as panels and objects of moderate detail including frames, furniture, and architectural elements. The gessoed object is then allowed to sit overnight to thoroughly dry before further surface treatment.

There are different ways to smooth gesso, the most common today being sanding. I like using 3M Tri-M-Ite sandpaper as it holds up well and cuts through the gesso efficiently (I do not find Garnet Paper to be very effective in sanding gesso as it clogs the paper too easily). Primarily, I use either 220 or 320 grit, depending on the surface and how aggressive the sanding needs to be. As a rule of thumb I recommend using as fine a grit as possible while still being able to efficiently sand the surface. If the finer 320 grit works well there is no need to use the heavier coarse 220 grit which will leave heavier sand marks than the 320.. If 220 is used, follow-up with a sanding of 320 grit and a final sanding with 600 grit wet or dry paper used dry. The 320 amd 600 grits help to progressively remove or minimize any previous sandmarks. This is very important as these marks will telegraph-through to the layer of gold leaf which accentuates any imperfections in the gesso or subsequent layers of clay bole which is applied after the gesso has been sanded.

There are other techniques that may be used to smooth gesso. Cennino Cennini discusses in his 15th century treatise Il Libro dell'Arte (The Craftsman's Handbook) the use of 'little hooks' and a spatula to scrape gesso smooth as well as the use of water polishing with a damp rag. A method called re-cutting (reparure) prevalent during 17th century France and Italy, is still used today.

Punchwork And Other Gesso Treatments

Other treatments to gesso for aesthetic affect include Incising and Punchwork known as Granito which creates texture and often elaborate surface decoration as a compliment to the gilded surface. Another technique known as Sgraffito involves applying a traditional egg tempera paint over the burnished gold leaf followed by intricate etching of designs through the tempera paint to reveal the brilliant gold leaf ground. These two methods can also be combined where the revealed gold through the egg tempera is also delicately punched with metal tools or as I prefer, blunt pointed agate burnishers catching the reflection of light in a magical way.

Gesso Fridays Online

Traditional Gesso provides the foundation for Traditional Water Gilding. It fills the grain of wood, the intention of the ancient Egyptians to make an object appear as solid gold once gilded. It works with the subsequent layers of Clay Bole to allow the gold leaf to be brilliantly burnished.

This form of gesso is sandable allowing for an extremely smooth surface which makes it a wonderful surface for both traditional water gilding and mordant gilding, whether using oil size or water-based acrylic emulsion. As mordant gilding can’t be burnished with an agate stone as it is with traditional water gilding it therefore doesn’t require as many coats of gesso with six coats usually being sufficient to fill the wood grain.

Traditional Gesso is also useful for the egg tempera painter, Iconographer, as well as those working in oils or acrylics where a smooth absorbent ground is desired on a wood panel.

Although gesso is always a part of the long form Courses which I teach for Water Gilding and Gold Leaf Restoration I felt it would be beneficial for students to have an Online gathering place where they can simply come to learn how to make gesso. Gesso Fridays is easily accessible with an Online Weekly 90-minute class that is both Live and Recorded and includes a Question and Answer period during each Friday session. Since Gesso Fridays repeats each week it gives students flexibility to choose any Friday of the month to attend (except when the Online class is closed for holidays or to make room for the occasional trip for the in-person classes!). As an added benefit the recordings of the Live classes remain viewable by students for six months.

Gesso Fridays is suitable for gilders and Fine artists, both beginners and experienced whether this is a first-time experience in making traditional gesso or to gain new insight and perspective in its working properties. Gesso is a material that is fairly simple in its combination of just a few materials but still requires great care in its preparation which is what this class is all about. And with the frequency of a once-a-week class, if a student can’t quite make Sign Up today, there’s always tomorrow…

A Few More Notes

To explore preparing gesso and these various traditional gilding techniques offered both Online and in-person visit the Gilding Class Information page for more detail or go to the Book A Gilding Class page for an-up-to date class schedule and Registration. To Register for a Gesso Friday Class Visit the Gesso Fridays Online Sign Up Page to select your Friday of choice!

For this excellent Gesso Recipe for frames, furniture, plaster sculptures, gilded architectural elements, or for Fine artists who wish to Gesso Panels for their own works of art, visit the Recipes Section of this website and scroll down to the Traditional Water Gilding class and download the water gilding recipe .

Mecklenburg, Marion F. 1991. "Some Mechanical and Physical Properties of Gilding Gesso." in Gilded Wood Conservation and History, edited by Bigelow, D., Cornu, E., Landrey, G. J., and van Horne, C., 163–170. Madison, CT: Sound View Press