Oil Gilding is the process of using Oil-based size (glue) to adhere Gold Leaf, be it Loose or Transfer (Patent) to a particular surface or substrate, and is the only choice if gilding externally or damp conditions.
There are several types of oil size, ranging from quick drying sizes which are 1 hour or less in drying time (ie the time ready to apply the Gold Leaf) to slow drying sizes of 12 hours or more, and of course in oil gilding it is possible to use not just gold leaf of which there are carats from 24ct down to 6ct, but also a wide selection of other metals including Platinum, Silver, Copper and Aluminium at the gilders disposal.
After you have prepared the surface (see separate fact sheet on surface preparation) the next stage would be to apply the size. Gold size should be applied as thinly as possible with a good flat ox hair filling in brush (series 1392) This is an ideal brush for flat, moulding work with large wide bands, where you can define the edges with masking tape. Whilst if you are doing lots of carved narrow mouldings, round brushes made of a good hog hair is more beneficially. As mentioned above gold size is put on thinly and sparingly making sure all surfaces are evenly coated and there are no puddles or pools of size left, especially in carved or moulded areas. If this happens the gold leaf being 1-250,000 of an inch thin will drop into the pools and loose all of its lustre.
TESTING SIZE FOR THE CORRECT TACK
Because there are so many variables in this process, ie. drying time of size, thickness that the gilder applies the size and temperature and humidity conditions, this procedure of testing has to be visited by the gilder on a number of occasions. The ideal tack that the gilder is looking for before applying gold leaf is that of the dry tack of a post it note. Some people prefer to use the back of their knuckle or indeed the slight pull of the hairs on the back of one's hands will also work. However this is achieved, the thing always to remember is that the gold leaf has got to sit on the very top of the size in that area just before the product totally cures. The surface of the fresh size has a wet shine which when ready becomes just a little duller. The window on most oil size ie. the time you can apply gold leaf before the size dries completely, is usually hours long. To avoid dust settling on the surface of the size, if it is possible to stand the object vertically or indeed cover the work with a paper tent, reduces the risk of dust contamination.
GILDING WITH LOOSE GOLD LEAF
Loose Gold Leaf can be cut and applied to the work in a number of ways, most craftsmen develop their own specific ways of removing the gold from the booklet to the substrate that they are working on. Some Gilders and Signwriters seldom use a cushion and often use fingernails to cut the gold while the book of gold leaf is on one hand and a gilders tip in the other. However the traditional method used by most gilders that would work in a studio has not changed for hundreds of years. The gold is transferred from the book to a gilders cushion where with a accurate soft blow of air from the gilders mouth, flattens the gold to the cushion and allows it to be cut by a gilders knife into pieces, then a gilders tip (that is
lightly brushed across the bridge of the nose to pick up the faintest trace of grease) is placed onto the gold and the gold is then able to be lifted to the work. This process is repeated until the piece is fully covered in gold leaf. Once that is achieved a gilders mop made out of squirrel hair can be used to tidy up the work and brush all the excess gold (scewings) off the work. These can be kept and reused or alternatively sold back to the Gold Leaf Manufacturer for recycling.
Depending on the skill of the Gilder there may be places when gilding where the gold has not taken, this is called "faulting". When gilding over a coloured surface, faults will be easy to see but if you have used a tinted size which will be yellow in colour this may be harder to notice. Cut a leaf of loose gold leaf into small pieces to apply to the places that have been missed. If the size is almost dry, breath gently over the size and this should bring back some of the tackiness and allow the leaf to stick. If faults are found once the gold size has completely dried, a small amount of size will need to be re-applied, and preferably a clear size.
It is not always easy to judge the amount you can gild at one time or you may get called away from your work to which the gold size then becomes completely dry. If you then apply a second coat of gold size, once gilded this will look slightly different to work already done. You are therefore better to remove the dried size and start from scratch with just one coat. To remove the dried size, gently wipe over with white spirit being careful not to go over the already gilded surface. Before re-applying a new coat of size, the surface should be clean, dry and free from any dust.
GILDING WITH TRANSFER GOLD LEAF
Transfer Leaf is where the gold leaf is adhered to a piece of acid free tissue paper which acts as a carrier, therefore a gilders cushion, knife and tip are not required in the application of the leaf. Transfer Leaf is ideal for flat surfaces, but if the surface you are gilding is very intricate then loose leaf would be required. If you need to cut the transfer leaf into smaller pieces, this can be done with very sharp, clean scissors or blade. To apply the transfer leaf, hold the tissue on the border around the leaf and place gold face down onto the sized area. Gently rub the back of the tissue paper either with your fingers or a soft cloth, rubbing away from the border you are holding and then slowly pull the tissue paper away. When applying the second sheet of transfer leaf, you will need to overlap the leaf already down by approximately 3mm and keep repeating this process. Once you have finished gilding the surface you will need to look over you work for any faulting (as mentioned above in Gilding with Loose Gold Leaf Section).
TOOLS USED IN OIL GILDING
Oil-Based Gold Size - Lymmit Gold Size / Japan Gold Size / Le Franc Gold Size / One Shot Gold Size
Filling In Brushes - Series 1392, available in 12mm, 18mm, 25mm, 37mm, 50mm, 75mm and 100mm
Gilders Cushions - Series 3844 & 3844E - Available with Parchment Shield or Card Shield
Gilders Knife - Series 3834 & 3832 - Available in Stainless Steel and Carbon Steel
Squirrel Hair Gilders Tips - Series 1441 & 1442, available in Short, Medium and Long
Squirrel Hair Gilders Mops - Series 1420 & 1422, available in Sizes 2,4,6,8 and 10
Gold Leaf Loose & Transfer - Available in carats from 24ct down to 6ct, Palladium Leaf, Genuine Silver Leaf, Imitation Gold & Silver Leaf, Copper Leaf.
ALL PRODUCTS MENTIONED CAN BE PURCHASED FROM OURSELVES, PLEASE VISIT OUR WEBSITE - www.wrightsoflymm.co.uk
For further help and information on Oil Gilding the following publications cover this in great depth and can be purchased from ourselves -
Practical Gilding by Peter & Ann Mactaggart
Gold Leaf Techniques by Kent H Smith
Wrights of Lymm also offer a comprehensive range of gilding starter kits that would be ideal if you are looking to start gilding for the first time and the starter kits can be found on the Starter kits page of our website.