Gilding a picture frame is one of the most rewarding introductions to the art of gold leafing. Frames have manageable surfaces, clear edges and visible results — you can finish a small frame in an afternoon and have a piece that looks like it belongs in a gallery. Here is how to do it, whether you are using genuine gold or imitation leaf.
Preparation
Start with a bare or painted wooden frame. Sand the surface smooth with 220-grit paper — gold leaf is extremely thin and shows every imperfection in the surface underneath. Fill any dents, nail holes or grain texture with gesso (a traditional gilding primer made from chalk and glue) or a fine surface filler. Apply two to three coats of gesso, sanding lightly between coats with 320 grit, until the surface is uniformly smooth.
If you are gilding over an existing painted frame, check that the paint is well-adhered and smooth. Sand lightly to provide a key for the size (adhesive). Flaking or damaged paint should be stripped and gessoed from scratch.
Bole (optional traditional step)
Traditional water gilding uses a coloured clay called bole as a base layer under the gold. Red bole is the classic choice for warm, rich gilding — it gives a subtle warmth to the gold and provides the characteristic red glow that shows through at worn edges on antique frames. Yellow bole produces a cooler, brighter gold appearance. Blue or black bole is used under silver leaf.
Apply bole in thin coats with a soft brush, building up a smooth, even layer. Let each coat dry fully before the next. Bole is only necessary for traditional water gilding and burnished finishes — for oil gilding (the easier method), you can skip bole and work directly on the gessoed surface.
Sizing
Gilding size is the adhesive that holds the leaf to the surface. Oil size (also called gold size) is the easier option — apply a thin, even coat and wait until it reaches the right tack (typically 1-3 hours for quick-dry size, up to 12 hours for slow-set size). The size is ready when it feels sticky to a light touch but does not transfer to your finger. This is the critical moment — too wet and the leaf sinks into the size and loses its lustre; too dry and the leaf will not adhere.
Water size (rabbit skin glue) is the traditional method for the highest-quality work — it allows the leaf to be burnished to a brilliant mirror shine, which oil gilding does not. It requires more skill and speed, as the working time is shorter. For a first gilding project, oil size is the better choice.
Applying the leaf
Gold leaf is extraordinarily thin — a single leaf is about 0.1 microns thick, making it one of the thinnest materials you will ever handle. It reacts to the slightest breath, static charge or draught. Work in a still room with no fans or open windows.
Lift each leaf with a gilder's tip (a flat brush with a thin row of soft hair) — static from lightly brushing the tip against your hair or a piece of silk gives it enough charge to lift the leaf. Lay the leaf onto the sized surface, starting from one edge and letting it fall gently onto the tack. Press down lightly with a soft brush or a cotton pad to ensure full contact. Overlap each leaf by a few millimetres to avoid gaps.
Do not worry about wrinkles, tears or imperfect coverage at this stage — you will address those in the next step. Work methodically around the frame, covering all sized surfaces.
Patching and brushing
Once the entire frame is covered, let the size set for at least two hours (oil size) or until fully dry (water size). Then gently brush away the overlapping excess with a soft, dry brush — a wide gilder's mop or a soft make-up brush works well. The excess falls away as fine gold fragments (called skewings), revealing the clean edges and profile of the frame underneath.
Inspect for holidays (bare spots where the leaf did not adhere). Apply a small touch of fresh size to any bare areas, wait for tack, and patch with small pieces of leaf torn from your skewings or a fresh sheet. One round of patching is usually sufficient.
Burnishing (water gilding only)
If you used water size and bole, you can burnish the gold to a mirror-like brilliance using an agate burnisher — a smooth, polished stone mounted on a handle. Rub the burnisher firmly across the gold surface with steady, overlapping strokes. The pressure compresses the gold onto the bole and polishes it to a reflective shine. This step is what separates water gilding from oil gilding — the burnished result has a depth and brilliance that oil gilding cannot achieve.
Distressing (optional)
For an antique or aged look, gently rub through the gold at edges, corners and high points with fine steel wool (0000 grade) or a piece of denim. The bole or gesso underneath shows through, mimicking centuries of natural wear. Red bole showing through warm gold is the signature look of aged gilding. Stop frequently and step back — it is easy to overdo distressing.
Sealing
Genuine gold does not tarnish and does not strictly need sealing. Imitation gold leaf (which is brass-based) must be sealed to prevent tarnishing — a thin coat of shellac or a dedicated gilding sealer protects the surface. For both genuine and imitation leaf, a light coat of clear wax (applied sparingly and buffed gently) adds a subtle depth and provides a sacrificial protective layer.
