Water gilding is a highly skilled and very labor intensive technique. Each stage in the process is time consuming. The quality of finish is unrivalled and to an expert it is instantly recognizable. Used over the centuries on furniture and picture frames, Water gilding can only be used indoors and the process is the only way that the appearance of solid gold can be replicated. Today water gilding is used on frames for contemporary paintings and high quality reproduction frames of antique styles. Different gilding techniques are used in many areas of decoration and decorative arts such as on monuments, signs, and sculpture, etc. But none match the appearance of burnished water gilding. This guide is intended as a simple introduction to the work involved in creating a water gilded picture frame.

The process of covering wooden objects with thin gold leaf to replicate solid gold was used by the ancient Egyptians. Little has changed with the traditional method of water gilding frames that we use today since the Renaissance times, the older recipes and methods are perhaps more complicated compared to todays techniques but the core of the process is the same. It was during this explosion of artist and creative work that the frame as we know it developed from the integral ornate surrounds of altar pieces. With the huge increase in the production and availability of paintings came a need for simpler frames to surround and protect the art work. These early frames quickly developed into the varied styles that we have seen over the centuries. Gilding is still practiced in picture framing workshops and businesses today, There is an air of mystery around the art and many laymen have no idea how the process works. There have been some modern developments to the art but many gilders still use traditional techniques and materials to obtain the highest quality finish on picture frames. It is also true that there are many different recipes and each stage has numerous variations, and it could even be said; that each gilder has his own way of creating a water gilded finish. This guide is very brief and is as simple as possible description of one way of water gilding a picture frame, the subject is in fact vast and hold many interesting variations.

Size

The most common wood used today in picture frame gilding is called obeche which comes from North Africa. Once the frame has been cut to size, and any filling and sanding has been done the frame is ready to be sized. 1 part rabbit skin glue is put in a glass jar with 8 parts water (1:8) this is left to soak for a few hours or ideally overnight. The size is then heated in a double saucepan, it needs to be very warm but not overheated as this destroys the effectiveness of the adhesive. Once warmed it is brushed on the frame with a hogs hair brush, any excess is wiped off the surface. The frame is then left for a few hours to a day to dry.

Gesso

1 part rabbit skin glue is mixed with 10 parts water in a large saucepan, this is again left for upto a day before being heated in a double saucepan. Once the glue is warmed (but not hot) it is taken of the heat and sieved calcium carbonate (whiting) is added by spoon until no more whiting can be absorbed by the glue. It is left for 10-15 minutes before being gently stirred. It is important to introduce as little 'air' as possible to minimize air bubbles, this will cause imperfections in the final gilded surface. The finished liquid will be like single cream, this is brushed onto the frame. The second coat is applied when the first is 'matt dry', the time to apply the following coats is something that comes with practice, the surface should not be too wet or too dry. The gesso wants to be kept at as constant and as cooler temperature as possible. For high quality water gilded frames I would apply 8 coats of gesso. Today gesso can also be sprayed onto the frame.

Sanding

The gesso covered frame is left for a day to fully dry. The surface is then sanded and polished. This can be done with typical wet and dry paper or similar such as aluminium oxide paper. I usually start with 320 grit, then 400 and finally 800. The gesso can also be smoothed with damp cloths, called water polishing. An even more specialist and little practiced technique is called Reparure, French in origin it was used on very ornate frames where the gesso had been applied to finely carved details, the gesso would be worked and re-cut with metal tools to create very crisp detail.

Bole

This is very fine coloured clay that is again mixed with rabbit skin glue, 1 part glue granules are mixed with 13 parts water and as usual left to soak. The classic colour is red, but on antique frames yellow, black, grey, brown, and pink are also used. On modern frames red is still the most common but any colour is available. When soaked the glue is heated till warm. 1 part clay is mixed with 2 parts warmed glue. It is stirred and mixed thoroughly. This is applied to the frame with a good quality, fine brush (ox, sable or synthetic mix) I usually apply 4 or 5 coats. This is then left to dry over night.

Gilding

The bole is sometimes given a polish with wire wool, a stiff brush, or even worked with a burnisher, this will result in a higher quality finish but it is possible to gild without polishing the bole. Now we come to the laying of the gold leaf onto the prepared frame. This is where the name 'Water' gilding comes from. There are many recipes for 'gilders water', I take some distilled water (some people would use distilled water at every stage) and add a small amount of rabbit skin glue, this is heated and a dash of isopropyl alcohol is added. Some gilders just use pure water as there is glue in the bole and gesso which is activated when water is added. The gold leaf (3" square) is placed on a gilders cushion and cut to the required size with a knife, a piece is picked up with a special brush called a tip (made from squirrel or badger hair), then I use a ox/sable mix brush to wet the area where the first piece of gold is to be placed, the gold is offered upto the wet bole and is pulled off the tip onto the frame. This process is continued around the frame, each piece of gold laid down is overlapped slightly on the previous piece, to make sure there are no gaps in the gilding. As the water dries it will be necessary to go to the early laid leaf and press it gently with cotton wool to eliminate air bubbles and ensure a faultless finish. Once the frame is gilded it is left for a while to dry, the frame is gently brushed down to remove any loose leaf. Any areas where the gold did not stick are wetted and gilded again.

Burnishing

This process involves rubbing the gilded surface with a burnisher which is usually an agate stone, often shaped like a dogs tooth (which would have been used in older times) but many shapes are now available. This process condenses the surface, removes any crease in the leaf and creates a highly polished finish which perfectly replicates solid gold. The time when burnishing can successfully take place is critical, do it to soon or to late and the surface will be to wet or to dry and the finish will be spoiled. Water gilding does not have to be burnished, on some frames areas are left unburnished to create contrast on the surface. These areas would often be given a coat of weak glue size or micro-crystalline wax to protect them. The finished gilding is often lightly distressed with wire wool or other abrasive to reveal the coloured bole beneath, this will also reveal the overlaps in the gold leaf which is a classic indication of a water gilded frame.