Sgraffito: The Art of Etched Egg Tempera

There are many different treatments that can be added to gilding. Sgraffito is one of my many favorites. It’s a technique that like much of gilding has a very long history. It is also used on pottery to reveal an underlying painted surface but with traditional gilding it’s the application of Egg Tempera paint over the burnished water gilded gold leaf where a design is then etched through the paint to reveal the bright gold ground.

Sgraffito a beautiful technique that requires skill in the drawing and etching as well as in the traditional water gilding technique. I have found, however, that it’s also quite possible to perform Sgraffito over a mordant gilded surface using either oil size or a contemporary water based acrylic emulsion using any of the leafs available, from genuine 24k gold, White Gold, and Palladium leafs to Genuine Silver, Brass, and Aluminum leafs.

How To Make Egg Tempera

To prepare the egg temper paint first the pigment of choice is spooned onto a mixing plate. Slowly add distilled water through an eye dropper a few drops at a time. Using a small Conservator’s Spatula blend the pigment and water until the pigment is saturated but not runny. You want a paste-like mixture where you can draw up peaks when pulling up with the flat end of the spatula. When this is done you’re ready to prepare the egg tempera.

The egg tempera paint is prepared in the same manner used as the egg tempera artist: the pigment is made wet with the water and then the yolk is carefully separated from the white of the egg so the yolk doesn’t break. The egg should be fresh and preferably Organic from well-fed Hens, otherwise the yolk will easily break in your hands if it’s old.

The yolk is rolled from one hand to the other, wiping your hands on a paper towel as you go along until the outside of the yolk feels dried from the surrounding white.

The yolk is then held between your fingers in a ball and pinched or poked with a clean needle and the inside of the yolk is poured out into a small bowl. This separates the sack around the yolk which can then be pulled away allowing a smooth liquid yolk to be used as your tempera. The larger half of the egg shell is then used to measure and add one shell of distilled water into the yolk, gently stirred for thinning.

Now that the pigment, water, and egg tempera are prepared, combine equal parts of the wet pigment and egg tempera and blend them well while using the eye dropper to add a little extra water as needed for a thin consistency.

Applying Egg Tempera To Gold Leaf

The egg tempera paint is now applied to the water gilded surface, directly over the unprotected gold leaf. A little yolk or water may be added a drop or two at a time as needed while painting. A very important element to this technique is to keep the coats of egg tempera paint very thin. This is crucial, otherwise the paint can crack and peel over time but when applied thin can hold up wonderfully well. The paint will dry to the touch fairly quickly but allow it to set a bit until it appears flat and so the previous coat is not disturbed by the next coat. I find five thin coats sufficient for an opaque covering over gold leaf.

Being mindful not to accidentally scratch the surface in unwanted areas the etching can be done after an hour or so although I generally wait till the next day. During the Online Sgraffito classes the etching is done the following week and in my studio tests I find two weeks still allows an appropriate window to etch through the paint.

Granito: Punchwork and Incising

Burnished water gilded gold leaf has that unmistakeable glow that is revealed through Sgraffito which can be further highlighted with Punchwork where small  metal Punches, Agate Burnishers, or other such tools are used to tap small embossed patterns into the gilded gesso, catching and throwing the shimmering light which adds a touch of sparkle and complexity. This technique known as Granito it is also effective when used together with the use of a pointed agate burnisher to create incised lines that are drawn along a straight-edge compressing the gold into the gesso and boled surface that can appear as rays of light, often used as such in Iconography. Halos are drawn this way, often with use of a compass.

These design elements were used extensively during the Renaissance  although as Daniel Thompson points out in his book Medieval Painting the passage of time has reduced the brilliant effects of these embellishments to where our imagination needs to consider what this must have looked like when they were originally gilded.

Design templates are often a good way to create beautiful patterns with this ancient method. Those who are skilled Fine Artists will find this technique an extraordinary path for expression. ~

Sgraffito Classes

For those interested in learning Sgraffito there are various Online opportunities to learn this technique through Charles Douglas Gilding Studio. 3-Day Masterclasses are offered throughout the year as well as being a component of the 12 Week Online Course Water Gilded Panels: from Pastiglia to Sgraffito. There may also be upcoming In Person opportunities for 2023-2024. Visit the schedule on the Book-a-Class tab for the next Sgraffito class!

Traditional Water Gilding

Traditional Water Gilding is the oldest of all the gilding methods, with the origins of gilding dating back over 4,000 years ago to Northern Africa. The sheets of what we think of today as gold leaf were in its earliest form more of a thick foil which would be pinned to an object for ornamentation, often with Spiritual significance.

Very little has changed over the years throughout the history of Traditional Water Gilding. A surface foundation we call gesso today is still comprised of an animal-based glue and filler - rabbit skin glue and calcium carbonate or calcium sulphate - with a clay mixed with the glue and applied for color over the white gesso informing the tonality of this thin metal while also providing a cushion underneath the gold to aid in its burnishing. Today we usually use agate stones in various shapes for burnishing gold and silver leaf which makes the leaf shine and compresses it into the surface making it more durable in its bond to the surface. Historically, however, a dog’s tooth was used for burnishing as described by Cennini in his late 14th Treatise Il Libro dell’Arte - The Craftsman’s Handbook. Two translations are available, the earliest by Daniel Thompson (1954 is the first Publication by Dover) with the newest (2015) by Lara Broecke. There are other earlier translations of this intriguing writing of Cennino d’Andrea Cennini with each new translation correcting the previous.

One aspect of gilding that has changed throughout its history is the thickness of gold leaf due to the malleable characteristic of gold to be beaten thin, most notably with the progressive use of machinery taking the place of hand hammering, although still used to some degree by the goldbeaters. I was very fortunate to witness this ancient craft of gold beating when I visited the Manetti Gold Beating Factory in Florence where I watched as ribbons of gold were beaten and ultimately cut into 3 3/8 inch squares and packaged for delivery. A wonderful experience to be detailed in another story for another day.

Water Gilded Panels Class…Pastiglia to Sgraffito

The method of traditional water gilding can be seen on 13th and 14thc Florentine egg tempera panel paintings, a period which can be viewed as a point of reference for the online gilding class Traditional Water Gilded Panels…From Pastiglia to Sgraffito. Of all the gilding classes offered through Charles Douglas Gilding Studio this is the most extensive, meeting weekly for 12 weeks in includes the embellishment techniques of Granito, Pastiglia, and Sgraffito.

To grasp a full understanding of Traditional Water Gilded Panels students are taken through each step of this ancient method which include the following steps:

• Chamfering the panel’s edges

• Preparing the 10% Rabbit Skin Glue Size

• Sizing the Panel

• Applying and glueing Fabric to the Panel

• Preparing and applying Hard and Soft Gesso

• Sanding the Gesso

• Preparing and Applying Clay Bole

• Gilding in 23k Gold Leaf

• Burnishing

• Granito

Gilding Recipes For Gesso and Clay Bole

The recipes for the Rabbit Skin Glue (RSG) Size, Hard and Soft Gesso, and Clay Bole can be downloaded at the Charles Douglas Gilding Studio website under the Materials and Recipes Tab in the Navigation Bar. Students are shown in the online class how to properly prepare all of the materials and the panel for gilding in genuine 23k gold leaf. The gesso recipe was passed onto me many years ago based on an old English approach and later presented to be the best for its stability in a paper Titled Physical Properties of Gilding Gesso by Marion F. Meklenburg from the book Gilded Wood Conservation and History, edited by Deborah Bigelow who I was fortunate to have taken a class with in 1998 on the concept of Toning Gilding which was around the same time as the publication of what remains my favorite reference books on gilding.

During the Water Gilded Panels class students gain an understanding of the principles of how the system of Traditional Water Gilding works for stability of the gilding on wood, adhesion of gold leaf to the clay bole, how the gold leaf is burnished, and how the various decorative embellishments of granito, pastiglia, and sgraffito are performed.

Handling Gold Leaf

Perhaps the most challenging aspect of learning to water gild is the handling of the extremely thin gold leaf which can measure as thin as 1/250,000th of an inch (less than the width of a human hair). Despite the extreme delicate nature of this beautiful and malleable of all metals it can be managed and tamed and with time and correct practice students can become adept at handling gold leaf

Students are shown how to use the gilder’s main tools - the pad, knife, and ‘tip’, the thin-haired sable or squirrel hair brush used to pick up the gold leaf from the gilder’s pad where the leaf was cut with the gilder’s knife to the desired size off gold leaf with the knife. I also demonstrate cutting small pieces of leaf as tiny as 1mm for spot gilding, the practice of applying small pieces of leaf to spots where the gold may have been missed, generally from either a small air bubble or breakage in the gold.

Gold leaf is subject to various conditions which can be difficult to contend with especially for the beginner - static electricity in the room and on the pad or knife, knicks in the knife, insufficient skin or hair oil which is used to pick up the gold leaf (no, we don’t want static for this, no matter what you read elsewhere!), and often, that slight breeze from someone walking by that blows your leaf right off the table! But in time you’ll learn how to handle each of these situations and I personally guide you in each class that’s offered through demonstrations and discussion due to its importance.

Gilding The Panel

Each session for the online class Traditional Water Gilded Panels…From Pastiglia to Sgraffito involves 12 weeks of Study where students gather with me online weekly for 90 minutes. The first hour is dedicated to a specific step in the water gilding process for Panels with the remaining 30 minutes allowed for a Question and Answer period with the students, a dynamic aspect of the online classes where we can explore student’s questions in depth.

The preparation of the 12” x 12” Panel takes the first five lessons, from preparing the Size and Gesso to applying the five layers of silky smooth Clay Bole. We are then ready to begin gilding.

Both Single and Double Gilding are demonstrated in class where Double Gilding is simply applying a second layer of gold leaf over the first which provides for an absolutely fully covered layer of gold over the gessoed panel. The main objective of Double Gilding is to cover any areas where the initial single layer of gold leaf may have small holes from air bubbles, breaks in the leaf where the overall appearance of the gilding would be more uniform in its beauty by Double Gilding rather than simple spot gilding which can sometimes leave ghost images from general touch-ups.

A student’s gilding will become more proficient with time and better leaf-laying skills will leave fewer imperfections but there is sometimes the occasional mishap in water gilding where a second application of gold leaf can provide an overall more attractive appearance. These concepts of spot gilding, single gilding, and double gilding are all discussed and demonstrated during lessons 6-8 where the class is focused on laying gold leaf to the panel.

Burnishing, Granito, Pastiglia, Egg Tempera Sgraffito

…To Be Continued!