Basic Gilding Techniques for Illumination

From a class given by Mistress Caitlin FitzHenry, OL
Copyright 1998, Kathleen Whitley, All rights reserved



Materials and Equipment Also useful: Technique

Gilding takes some practice in using the materials, but is well worth the effort, creating a rich and glittering effect that is unequalled. Try out the techniques beforehand on a sample card, sketching out a few simple designs that use both small areas like leaves and tendrils, and larger flat areas. Remember that gesso and gum ammoniac used in gilding will gum up' and destroy brushes and pens, so you will want to use lesser quality implements and clean them as carefully as you can after use.

Gilding is usually done after completing the calligraphy on a piece, and before any painting is done. You may wish to cover any calligraphed areas with glassine or clean paper before gilding to avoid getting any stray flakes of gold leaf adhering to the ink.

The adhesives used for gold leaf and gold powder in traditional manuscript illumination are called 'water-based mordants', and include such substances as glair (denatured egg white), gesso sottile and garlic juice. Gesso sottile, one of the most commonly used mordants, is a combination of a white pigment (traditionally white lead), a glue (traditionally hide glue or fish glue), a filler (powdered chalk or gypsum), a hydroscopic agent (sugar or honey, which retain moisture), and a colorant (Armenian bole). Traditional gesso sottile is somewhat brittle and tricky to work. For learning how to apply gold leaf, a modern acrylic gesso, with sugar and colorant added, and polymer adhesives are easier to use, and have the advantage of not requiring lengthy and arduous preparation.

Applying gesso evenly demands care. Work on a flat surface to avoid pooling of gesso at the bottom of the gilded area. Mix the gesso carefully to the right consistency, and avoid putting air bubbles into the mixture. Always work "wet into wet", placing the brush downinto a wet area, covering the adjacent dry areas fairly quickly, and then trailing the brush back into the wet gesso before lifting the brush and reloading it with gesso. This will minimize brush strokes and unevenness in the gesso. Try to apply a few thin even coats rather than one heavy coat, and allow the gesso to dry completely between coats.

If you apply gesso with a pen nib, It must be thinner in consistency that when you brush it on. Pen application is done with two strokes: one pulled stroke to create the banks of the river", and then a pushed stroke along the same path without lifting the pen, to flood the area with gesso and "fill the river".

Once the gesso is completely dry, have all materials close at hand, on one side of your work area. Clean your burnishers , scissors and tweezers with alcohol occasionally as you work, to prevent gold from sticking to them. Also, try to work in a draft-free place to avoid the gold being blown away by stray breezes.

Cut a small piece of gold leaf from the back leaf of the booklet, and lay it nearby on a piece of clean paper, or a gilder's pad if you have one, using tweezers to avoid getting oil on the gold from your fingers. The gold should be slightly larger than the area to be covered. If you are gilding a large flat area, you will lay several pieces of leaf down, slightly overlapping them like shingles on a roof to cover the entire area.

Now, breathe several times on an area of gesso through a drinking straw to direct the breath on the area to be gilded. Experience will tell you how much is needed, depending on the relative humidity that day. Humid days are best for laying gold leaf and dry days for burnishing it. Try to avoid getting any saliva on the gesso, as it will make the area too sticky to be gilded, and will need to be allowed to dry again before gilding.

Once the gesso is activated, quickly pick up the gold on its backing paper with tweezers, and lay it down on the gesso. Cover with glassine, and press firmly with the ball of your finger to adhere the gold leaf. Now before lifting the glassine, run a pencil point or stylus around the edges of the gilded area to press the edges firmly down. Lightly burnish over the glassine with a dogtooth agate burnisher to adhere the leaf securely to the gesso. Lift up the glassine, and lightly brush away the excess gold with a soft brush. If you wish, you can save the scrap gold for patching small areas, or for grinding into shell gold.

Continue covering all the gessoed areas with gold leaf. Allow the leaf to rest before final burnishing. Burnishing should be done on a dry day. Burnish lightly at first through glassine to smooth the gesso, then add more pressure. A final burnishing can be done directly on the gold leaf. Practice will teach you how hard to burnish the gold before you scratch it, or before the gesso melts and bleeds through the minute pinholes in the gold leaf. Once the gold is burnished, you may lay additional layers of leaf to give a rich color, and to avoid any further bleeding through. I always recommend laying at least two layers of 'double-weight' gold leaf for the best effect.

Gilding with gum ammoniac or white glue gesso follows the same basic procedures. However, flat gilding does not burnish to as high a gloss as raised gilding, and acrylic gessos will not burnish as bright as a traditional slaked plaster gesso.

Two basic recipes for easy-to-use gesso sottile:

MASTER ROBERT'S ALL-ACRYLIC GESSO SOTTILE

Procedure: Take a small volume of distilled water (about 1/4 cup or so) and add granulated sugar, spoonful by spoonful, stirring until sugar dissolves. At some point, you will have residual sugar that does not dissolve into solution. Allow water to stand overnight, stir and use as saturated sugar water in recipe. Mix all Ingredients thoroughly with a small amount of gouache paint or dry pigment for colorant if desired.

MISTRESS CAITLIN'S SURE-FIRE NEVER-FAIL ACRYLIC GESSO SOTTILE

Procedure: Mix all Ingredients together in a mortar with pestle, grinding out any lumps in the pigment as you mix, until the gesso is perfectly smooth. You may thin this gesso with water if needed for use with a pen or fine brush. This version of acrylic gesso sottile may also be scraped lightly with a sharp knife to smooth out any uneven areas. Gesso gives best results if allowed to rest for a few hours before applying gold leaf and burnishing directly on the gold. If weather is humid, allow gesso to rest again between Initial application of gold leaf and burnishing directly on the gold.

And just to show that it gilding can be done with minimal fuss:

WHITE GLUE GESSO SOLUTION

Procedure: Add approximately 1/4 tsp. of confectioner's sugar to 3 Tbsp. glue. Dilute If needed with water. If gesso is too sticky , add more white glue. Unlike the gesso recipes above, this glue gesso cannot be scraped smooth before use. This solution gives a very smooth, mounded surface, and is best used on small areas to avoid dimpling in the center of the gesso.

GUM AMMONIAC SOLUTION FOR FLAT GILDING

Procedure: Place a few crystals of gum ammoniac in a small plastic or glass container with a tight-fitting lid. Barely cover the crystals with water. Allow crystals to soak for 12 to 24 hours, shaking occasionally, until the liquid is milky and acrid. Strain through a piece of nylon stocking to remove any impurities. Add a small amount of gouache paint or dry pigment to color.

SOURCES FOR MATERIALS

The Bookbinder's Warehouse
31 Division Street
Keyport NJ 07735
Tel: (908) 264-0306
Fax: (908) 264-8266

Small and friendly company with a good selection of calligraphy and bookbinding tools and supplies. Source for parchment and vellum, gilding supplies, adhesives, and instructional materials.

Talas
568 Broadway
New York, NY 10012
Tel: (212) 219-0770
Fax: (212) 219-0735

Complete range of bookbinding, art conservation and archival tools and supplies. Source for parchment and vellum, agate burnishers, gilding supplies, adhesives, glassine, and silicon release paper.

John Neal, Bookseller
1833 Spring Garden Street
Greensboro NC 27403
Tel: (910) 272-7604
Fax: (910) 272-9015

Broad selection of calligraphy, gilding and illuminating supplies. Good source for specialty pens, nibs, inks, burnishers, gilding materials including gum arabic and gum ammoniac, and books and instructional videotapes on calligraphy and illumination.

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