Kölner Fond is a water-based burnishing clay for creating intensely shiny and reflective gilded surfaces. Kölner Fond simplifies the process of water gilding by combining the traditional gesso and poliment/bole into one product. There’s no more need to warm your bole in a bain-marie! Fond is applied directly from the bottle to the surface using a brush.
By building up many layers (at 4+ layers are recommended) of Fond and then polishing it with a cloth you can create a mirror finish surface. Then, activate this surface using Kolner Colnasol. This will create a surface which, when leaf is laid on it, creates a finish with a lustre and brilliance like water gilding. You can also gild on this surface using traditional methods. Kölner Fond makes for a great base colour for gilding on using oil- or water-based sizes.
When using Kölner Fond please bear in mind the following points –
Stir Kölner Fond before any use. Never shake the bottle or product, this will create air bubbles that will spoil the surface.
Apply at least 4 layers of Fond. In some cases, depending on the relief of the surface, you will need to apply more layers of Fond. For application and burnishing of metal leaf ensure there is a dry film thickness of 150 µm where leaf is to be applied.
After the last layer has dried polish it with a damp cloth. Then, polish it with a dry cloth until it shines. The shine that you get on the last Fond layer will be the shine you get after applying the metal leaf. The better the shine of the Fond the more brilliant the shine of your metal leaf will be!