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GILDING


GILDING A GUAZZO WITH ZECCHINO GOLD LEAF

Let’s take some time to explore together how to perform water gilding from start to finish. This technique is both complex and ancient but can be reproduced using traditional materials and the equipment from the Ca’ D’Oro line.
Water gilding traditionally uses 24-karat gold leaf, but let’s take a comprehensive look at the materials and tools required for the process:
- Water: First and foremost, all these materials are prepared using simple tap water.
- Rabbit skin glue: Essential for preparing the base.
- Bologna chalk (gesso): Used for creating the foundational surface.
- Natural bole: Yellow or red if applying gold leaf, or black for silver.
- Fish glue: For additional adhesion and finishing.
- 24-karat gold leaf: The main decorative element.
wood gilding | Borma Wachs | BPS srl
wood gilding | Borma Wachs | BPS srl
As for equipment:
- Gilder’s cushion and knife Gilder’s flat brush
- Soft brushes, including one specifically for applying bole
- Burnishers made of agate stone, in various shapes
- Electric heater
- Gilder’s pot
- Various containers
What Surface Should We Use?

It is not necessary to select high-quality wood. Water gilding can be performed on various types of wooden supports or derivatives, provided they are dimensionally stable (as a large amount of water is involved). Materials like plywood or MDF are suitable and commonly used. However, keep in mind that the rougher, more absorbent, or porous the raw surface, the longer the preparation of the base will take.

To achieve a smooth, dense surface that maximizes the brilliance of the 24-karat gold leaf, special attention must be paid to base preparation.

Isolating the Surface
1. Prepare Rabbit Skin Glue:
- Soak the glue in cold water until it swells.
- Dilute the resulting gelatin with warm water (10 parts gelatin to 90 parts water).
- Ensure the mixture is kept warm during use, but do not exceed 60°C to prevent irreversible degradation of the glue. Use an electric heater on the lowest setting.
2. Apply the Glue:
- Use the diluted solution to coat the surface evenly. This acts as a sealer or pore filler, facilitating the application of the gesso layer.
3. Drying Time:
- Allow the layer to dry for at least two hours.
- Achieving good results in water gilding requires ensuring each layer is fully dry before applying the next.

This preparation ensures a stable, smooth foundation for subsequent layers, enhancing the final gilded finish.
Sifting and Preparing Bologna Chalk

The gesso base must be built layer by layer, with each application varying slightly in composition. Here's how to proceed:

Step 1: Sifting Bologna Chalk
- Why sift the chalk? Bologna chalk is a hygroscopic material that absorbs moisture over time, forming clumps. These must be removed before mixing with the glue solution, as dissolving clumps directly in the mixture is challenging.
- Sifting aerates the chalk, improving its wettability when mixed with the glue solution.
Step 2: Preparing the Gesso Mixture
1. Start with the same diluted rabbit skin glue (“colletta”) used for sealing.
2. Gradually add the sifted chalk to the glue, allowing it to hydrate properly. Add small amounts at a time to ensure even mixing and avoid lumps.
Step 3: Applying Gesso Layers
1. First Layer:
- Apply the initial gesso mixture evenly over the surface. Allow it to dry thoroughly.
2. Subsequent Layers:
- Increase the amount of chalk in the mixture progressively for each new layer.
- Let each layer dry completely before adding the next.
3. Final Sanding:
- Once all layers are applied and fully dried, sand the surface using 240-grit sandpaper.
- Aim for a smooth, compact, and soft finish, ready for the next steps.

Key Notes
The preparation of the gesso base is critical for achieving a flawless water gilding finish. Take the necessary time for proper drying and ensure each layer is applied carefully to create a durable, even foundation.
wood gilding | Borma Wachs | BPS srl
wood gilding | Borma Wachs | BPS srl
Applying the Bole

After completing the gesso base, the next step in water gilding is applying the bole. Here's how to proceed:

Step 1: Preparing the Bole Mixture
- Combine bole with warm rabbit skin glue (“colletta”) at a ratio of 300 g of bole per 1 kg of colletta, creating a brushable liquid.
- What is bole?
Bole is a natural clay that serves several important functions in the gilding process:
1. Seals the gesso layer: Prevents the subsequent glue application from being fully absorbed.
2. Provides a colored base: Enhances the appearance of the metal leaf:
- Yellow: For a classic gold finish.
- Red: For an antique gold effect.
- Black: For silver.
3. Burnishing layer: Can be polished with an agate stone for added brilliance.
4. Adhesive property: Bole reactivates when moistened, becoming tacky to hold the metal leaf.

Step 2: Applying Bole Layers
1. Application:
- Apply 2–3 coats of the bole mixture with a light, precise touch, ensuring even coverage over the sanded gesso base.
- Use a crosshatch technique (alternating brush directions) to achieve uniform results.
2. Drying:
- Allow each coat to dry fully before applying the next.
3. Optional Burnishing:
- Once dry, the bole can be polished with an agate burnisher to enhance its smoothness and brilliance, preparing it for optimal gold leaf application.

Step 3: Preparing the Fish Glue
- Like rabbit skin glue, fish glue should be soaked in cold water until swollen, then dissolved in warm water.
- Dilute at a ratio of 1 part fish glue to 10 parts water. This solution will be used later in the gilding process.

With these steps, the surface is now ready for the final stage: applying the gold leaf.
Applying the 24-Karat Gold Leaf

Step 1: Cutting the Gold Leaf
- Use a gilder’s cushion and gilder’s knife to cut the gold leaf into smaller pieces.
- The size of each piece should be tailored to the shape and dimensions of the surface being gilded.

Step 2: Applying Fish Glue
- Warm the prepared fish glue and apply it to small sections of the surface at a time to ensure it remains fresh and tacky.
- Use a brush to spread the glue evenly over the designated area.

Step 3: Transferring and Placing the Gold Leaf
1. Use a gilder’s flat brush to carefully pick up the gold leaf from the cushion.
2. Place the leaf onto the freshly glued area, ensuring it adheres smoothly.
3. Gently press the leaf down to secure it, smoothing it over the surface.

Step 4: Drying and Finishing
- Allow the gilded surface to dry for at least 24 hours.
- Once dry, polish the gold leaf using cotton wool to enhance its shine.
- For additional brilliance, burnish the surface with an agate stone, if desired.

Final Note: No Additional Protection
- Traditional water gilding with 24-karat gold leaf typically does not require any additional surface protection. This preserves the unmatched brilliance and natural quality of the noble metal.

Your object is now beautifully gilded with a radiant finish!
wood gilding | Borma Wachs | BPS srl