How to Apply Gold Leaf, a Gilder's Guide

To apply gold leaf by the oil method, you prepare a smooth, sealed surface, brush on a thin, even coat of oil gold size, wait until the size reaches the right tack, then lay the leaf onto it, press it down gently, brush away the loose flakes and, where the metal needs it, seal it. The skill is in the details, above all in judging the tack and in handling a sheet of metal so thin it will drift away on a breath.

This guide walks through oil gilding step by step, the method used for most gilding on walls, mouldings, signs and furniture. We have checked the technical points against gilding suppliers' guides and conservation sources, and we finish with honest advice about when to call a professional gilder.

What you need before you start

Oil gilding needs only a short list of materials. Gold leaf comes in small books, either as loose leaf or as transfer leaf, which is lightly pressed onto a tissue backing for easier handling. You also need an oil gold size, which is the adhesive, a soft brush to apply it, a primer or sealer for your surface, and a soft mop brush or cotton wool for finishing.

Loose leaf calls for three traditional tools. A gilder's cushion is a padded leather board the leaf rests on, a gilder's knife cuts it, and a gilder's tip is a very flat, wide brush used to lift the leaf and carry it to the work.

The leaf is astonishingly thin. Britannica puts it at roughly one 280,000th of an inch, which is why gilders work away from draughts.

Step one, prepare and seal the surface

Gold leaf hides nothing. Supplier guidance warns that brush marks, dust and other faults are greatly exaggerated once the leaf goes on, so fill, sand and dust the surface until it is as smooth as you want the finished gold to look.

Porous surfaces such as bare wood or plaster must be sealed so that the size sits on top rather than soaking in. With an oil size, the usual choice is an oil based primer or paint, or shellac. The colour of the ground matters too, and one supplier guide notes that a red beneath gold gives a warm, rich finish.

Step two, apply the size and judge the tack

Brush the size on as thinly and evenly as you can, and avoid letting it pool in corners and creases. Only size where you want gold, because leaf will stick to all of it.

Oil sizes are sold according to how long they take to become ready. Quick sizes typically reach tack in about one to three hours, slow sizes in around twelve. A slow size gives a longer window to work in, which helps on larger areas. Always follow the instructions for your size.

Tack is the moment the size is no longer wet but still sticky. One supplier describes it as feeling like the back of a piece of sticky tape. A common test is to draw a bent knuckle lightly across the surface. If there is a slight pull and a faint squeak, it is ready. Too early and the size is still wet, too late and it will no longer hold the leaf, so it pays to test small areas often.

Step three, lay the leaf

Laying transfer leaf

Transfer leaf is the easier place to start. Hold the sheet with the gold facing the sized surface, press it on, and rub the back of the tissue gently with cotton wool or a soft brush. Peel the tissue away and the gold stays behind. Supplier guides recommend transfer leaf for flat areas and for outdoor work, or anywhere loose leaf would be at risk of blowing away.

Laying loose leaf

Loose leaf takes more practice. Tip a sheet out of the book onto the cushion, cut it if needed with the knife, then lay the gilder's tip on top of it. Gilders often brush the tip lightly against a piece of wool first, which helps the leaf cling to it. Carry the leaf to the work, lay it flat onto the size and settle it with a couple of light taps.

Whichever leaf you use, overlap each sheet slightly over the last, by a couple of millimetres, so that no gaps are left. Gilders call those bare patches holidays.

Step four, finish and seal

Once the leaf is down, press it gently into the size with a soft mop or cotton wool so it follows the surface. When it has had time to grip, brush away the loose, ragged edges. These scraps are called skewings, and supplier guidance suggests using them to fill any small gaps and holidays.

Oil gilding cannot be burnished to a mirror shine with an agate stone. That polished look belongs to water gilding, explained in our guide to water gilding vs oil gilding. What you can do is buff oil gilt lightly with a soft brush or a pad of cotton wool, which brings up a soft, even lustre.

Whether you then seal depends on the metal. Supplier guidance is that gold of 22 carat and above does not oxidise and needs no sealant, so it is often left bare. Lower carat gold, silver, copper and most other metal leaf need protection, especially where they may be touched.

Imitation leaf, often called Dutch metal, is a copper and zinc alloy that the Museum of Fine Arts, Boston describes as tarnishing rapidly, so it must always be coated with varnish, shellac or wax. Let the size cure fully before you seal. Depending on the size, one supplier suggests waiting anywhere from a day to a month. Our guide to gold, silver and copper leaf explains each metal.

When to call a professional gilder

A small frame or craft project is a good way to learn, and transfer leaf can give lovely results at home. Some jobs are better left to a gilder.

• Antique or valuable pieces with original gilding, where the wrong product or method can damage what is there.
• Large areas such as walls, ceilings, domes and alcoves, where the size has to reach tack evenly across a big surface.
• Cornice, ceiling roses, panel mouldings, columns and corbels, where the gold has to be picked out cleanly along fine detail.
• Lettering and signs, especially on glass, where the work is done in reverse.
• Anything that calls for water gilding and a burnished finish.

Zavoré gilds by hand in gold, silver and copper leaf, and in imitation leaf, using both water gilding and oil gilding. We work on walls, ceilings, domes and alcoves, pick out cornice and mouldings, gild backgrounds for murals, restore and regild mirrors, frames, furniture and objects, and lay gold leaf lettering and signs on boards and glass, across the UK including London, Birmingham and Manchester.

Questions we get asked

Can I use ordinary glue instead of gold size?

Gold size is made for the job, drying to a controlled tack that holds the leaf. Water based sizes are also sold and reach tack quickly, but supplier guidance is that they are not suitable for exterior work, so oil size remains the usual choice for anything outdoors.

Does real gold leaf need sealing?

Gold of 22 carat and above does not tarnish and is usually left unsealed. Lower carat gold, white gold, silver, copper and imitation leaf all need sealing to stop them tarnishing.

Can you burnish oil gilding?

Not to a mirror finish. Oil size cannot be burnished with an agate the way water gilding can. It can be buffed gently with cotton wool or a soft brush for a soft sheen.

How long does gold leaf last?

Building conservation guidance says unvarnished interior gilding should last almost indefinitely, while exterior gilding is exposed to the weather and eventually needs renewing.

Where to go next. See our gilding service to find out how we work, or read about gilded mirror restoration. When you are ready to talk about a project, get in touch, email support@zavore.co.uk or call or WhatsApp 07592 929191.