How to burnish genuine and metal leaf surfaces.

Burnishing is the process of cleaning or polishing genuine or imitation metal leaf.

Two Meanings of “Burnishing” in Gilding

The term burnishing is commonly used in gilding, but it can refer to two different—though related—processes. Understanding the distinction is important, as they are not interchangeable.

• Burnishing (Traditional Water Gilding)
  This refers to the use of a polished agate burnishing stone over a properly prepared gesso and clay (bole) surface to compress the gold leaf and create a true mirror-like shine. This technique is exclusive to Traditional Water Gilding and requires a hardened, polished gold surface. Agate stones are used only for this purpose.
• “Burnishing” (General Gilding Usage)
  In non-traditional or non-water gilding techniques, the term is often used more loosely to describe the removal or cleaning of excess metal leaf from a newly gilt surface. This process does not polish the metal or increase its shine—it simply tidies the surface and defines edges. Soft Goat hair Mop brushes, cotton and chees cloth can all be used in 'burnishing' genuine and metal leaf. No burnishing stone is involved.

While both uses involve finishing a gilded surface, only traditional water gilding burnishing actually polishes and densifies the gold. The second usage is a common shorthand, but technically refers to cleaning rather than true burnishing.

This technique is an essential part of the traditional water gilding method, resulting in a brilliant mirror shine.

Understanding Agate and Stone Burnishing Tools

Burnishing tools, typically made from agate stone, are essential for the traditional water gilding process. These tools are designed with a metal collar and a wooden base, and they come in various shapes and sizes to suit different gilding needs. Common shapes include houndstooth, wide, flat, pointed, and lipstick.

The Burnishing Process:

Preparation: Begin by preparing your surface with layers of gesso and traditional clay bole. The clay bole should be finished to an ultra-smooth and firm surface.

Applying the Leaf: Each sheet of gold, silver, or palladium leaf is applied one at a time using a rabbit skin or hide glue adhesive, often referred to as gilding 'liquor'.

Drying: Allow the applied leaf to dry completely before burnishing.

Burnishing: Using an agate burnisher, aggressively rub over the gilt surface. This action compresses the bole substrate beneath the leaf, causing the gold or silver to achieve a brilliant mirror shine.

Tips for Effective Burnishing:

Pressure and Technique: Apply consistent pressure while burnishing. The goal is to compress the clay bole substrate without tearing the delicate leaf.

Tool Selection: Choose the appropriate burnisher shape based on the area being gilded. Smaller, pointed tools are ideal for intricate details, while larger, flat tools work well for broader surfaces.

Practice: Burnishing requires a delicate balance of pressure and movement. Practice on test pieces to refine your technique before working on your final project.

Why Use Agate Burnishers?

Agate burnishers are preferred for their smoothness and durability. The fine, polished surface of the agate stone allows for a high-gloss finish without scratching the delicate metal leaf. The various shapes available ensure that you have the right tool for every aspect of your gilding project.

Application Examples:

Icons and Religious Art: Achieve a luminous finish on religious icons, enhancing their spiritual and visual impact.

Furniture and Frames: Restore and decorate furniture and frames with a brilliant, professional finish.

Fine Art and Calligraphy: Use burnishing techniques to add a polished touch to illuminated manuscripts, calligraphy, and other fine art projects.

By understanding the tools and techniques of burnishing, you can elevate your gilding projects to achieve stunning, professional results.