GILDING is a term usually understood to apply not only to the art of affixing gold leaf, but all other leaf or powdered metals to the surface of wood, paper, stucco, glass, metals, textiles, etc. Thus it covers bronzing and lacquering.
Before dealing with the actual practice of gilding and bronzing it will be necessary to pass in brief review the various materials and tools used.
Gold is available in the form either of leaf or of powder. Gold Leaf is prepared by rolling thin sheets of pure gold, alloyed with a small amount of silver, copper, or other metal, in presses and subsequently placing the thin sheets between vellum sheets, and finally gold beaters’ skin, and flattening them out with hammers. The hammering is a long process, repeated many times with hammers of ever-diminishing weights. In this way the leaves are reduced to about aobToo&th. of an inch thick. These leaves are cut into 3J- inches square (or other dimensions according to order) and laid between the leaves of small books, the pages of which are rubbed over with powdered bole to prevent sticking. Each book contains twenty-five leaves. The gold should assay at about 22 carats. Colour variation is controlled by the kind and amount of alloy used as well as the origin of the gold itself. The range of colour is from red, orange, extra deep, medium (or ‘ regular ‘ and ‘ ordinary ‘), deep, pale, citron, green, lemon to white. Usually lemon and white are worth about one-third less than the red, orange, and extra deep. Special leaf gold (for applying to exposed ironwork, etc.) is supplied in leaf about double the thickness of the ordinary. For very delicate work extra-fine leaf is supplied of very pure gold, not less than 23 carats. This is very expensive. Gold leaf for gilding glass is put in books without the intervention of paper covered with bole, but these books require most careful handling and storing, as dampness will cause the leaves to stick together, so ruining them. As the extremely fine gold leaves are very light and are easily blown away, ‘ transferred gold ‘ is often preferred, especially for outside work. In this case the gold leaf is pressed against white tissue paper, to which it closely adheres until pressed against some more adhesive substance. This makes handling much easier. Ribbon Gold consists of gold leaf cut in thin strips and transfer-pressed upon a roll of thin paper. This ribbon gold is made in various widths for line gilding and is usually applied by means of a gilding wheel. Powder Gold is prepared by a long process from leaf gold; it is commonly supplied in the form of ‘ gold tablet,’ or ‘ illuminating gold,’ the powder mixed with weak gum water being formed into tablets in moulds, or as ‘ shell gold,’ the powder and medium being dried in mussel or other shells.
Gold Substitutes are numerous. The most commonly used are Dutch or Bundle metal, an alloy of copper and zinc, which has a high lustre, but requires to be protected by transparent lacquer to prevent tarnishing; imitation Abyssinian or composition gold, alloys of copper and tin, possessing a good colour and less subject to oxidation than Dutch metal; aluminium gold, gold substitute and ducat gold, alloys of copper and aluminium, excellent of colour and slow to oxidise when under a coat of lacquer.
Gold Paint and liquid gold are bronze powders held in suspension in a suitable liquid medium. They are useful for temporary decorations, or on cheaper work to be covered with a coat of lacquer, as they will soon tarnish if exposed unprotected to the air.
Platinum is sold in leaf form, for application as in gilding, but, though valued for its greyish hue and its untarnishable properties, the high price of the metal makes its use nearly prohibitive.
Silver Leaf is prepared much in the same way as gold leaf, but is nearly three times as thick, as the metal is not so ductile. It is much easier to handle than gold leaf, but quickly tarnishes on exposure to air. When used it requires to be protected by lacquer.
Aluminium Leaf, or white metal, though duller than silver, does not tarnish and so is more useful. Tin leaf, or also known as silver substitute, more closely resembles silver, with its beautiful bluish sheen, but is less adherent and dulls more quickly than aluminium. Polished and lacquered aluminium will look almost as bright as polished silver.
Tin Leaf and Dutch Metal may advantageously be used as foils, to be covered with transparent coloured lacquers, or as backgrounds for decorative painting subsequently to be covered with transparent lacquer.
Copper Leaf, much thicker than gold leaf, is to be procured in different tones. On exposure it oxidises to a deep red, which, however, is apt to degenerate into a dullish brown. This can be corrected either by occasional burnishing or by lacquering. Its rich warm tones make it a useful aid in decoration.
Bronze Powder is a term employed to describe all metallic powders, whether prepared from bronze, copper, silver, aluminium or alloys, consequently the range of colour is extensive. They are not to be recommended for high-class work, but the best qualities are fairly durable under lacquer and are invaluable for temporary decoration of all kinds.
Under the name of Speckles, Specks, Spangles, Jewellery, Brocades, Frosting, etc., tiny metallic flakes are sold for producing a glittering effect under lacquer or on lettering or for temporary decoration. Brocades are cut from coloured leaf metals.
Metallic specks are cut from sheets of mica or celluloid, gilded or lacquered in different colours, on one side or on both; shell speckles are the same as the last-named, but the specks are made to cockle up in concave form.
Bronze paints, like liquid gold, are to be had under various proprietary names, the manufacturers making use of special powders and mediums.
Mordants is the name given to the various binding materials used as an adhesive coat for attaching the metal, either in leaf or powder form, to a surface. For exterior work, relief work, or work which is washed periodically, either old oil gold size or japanners’ gold size is employed. For interior work, such as frame or glass gilding, one of the various water sizes is commonly used.
Old Oil Gold Size
This is prepared by allowing pure raw linseed oil to stand in an open jar for from six to twelve months, each month removing the skin which forms on the surface. When the oil has attained the right degree of tackiness – which can only be determined by experiment – it should be transferred to a closed vessel, adding a small quantity of litharge (1 oz. to the lb.) and a little raw sienna, to provide suitable colouring; these should be well stirred in and the container securely corked. If, on using, it seems too thick for spreading to a thin, even coat, a little boiled linseed oil may be added.
Japanners Gold Size
This is a transparent, varnish-like liquid, ready for use, ranging in colour from pale to dark.
Its advantage lies in the comparative rapidity with which it dries, but against this must be set certain definite disadvantages. The gloss on the face of the gilding is not so deep as that which results from the use of old oil gold size, nor is the gilding so permanent.
The present-day demand for speed, however, has considerably increased the use of japanners’ gold size, and, generally speaking, the results which this gives are very satisfactory. The chief difficulty lies in gauging the right moment at which the leaf should be applied; the surface of the size, while retaining a certain degree of tackiness, should be unaffected by gentle pressure.
As mentioned, gilders often darken oil gold size and japanners’ gold size by adding a little raw sienna, Italian ochre or chrome, ground in oil. A dark luminous mordant is considered to act as a good foil for the gilding, ensuring greater depth and lustre.
A slow-drying japanners’ gold size is sold as ‘ writing gold size ‘ for use in lettering, ticket-writing, etc.
This is simply a weak solution of isinglass, made by-pouring a pint of boiling water on to a teaspoonful of shredded isinglass in a clean vessel, covering it over and leaving it to dissolve for about twenty minutes. It is then stirred and strained through cotton wool. For best results it should be used while very warm.
Mat Gold Size (for frames and smooth surfaces) is prepared by mixing eight ounces of gilders’ clay, or fine clay, or Armenian bole with one ounce of mutton suet, straining through muslin and then adding sufficient hot parchment size, or hot leaf gelatine size, to make the substance into a thick cream. Four to six coats of this are applied before gilding, each coat being allowed to dry before another is applied.
Burnish Size is prepared as above, but with the addition of one ounce of blacklead to the paste. This is used when the gold is to be finished with a high burnish, as it gives a stronger backing.
Egg Size is prepared by beating up equal parts of yolk of eggs and glycerine with a little water. It is useful for applying gold leaf or powder to paper and other absorbent surfaces.
Gum Water (a weak solution of gum Arabic in water) an inferior alternative used for this purpose.
Jewelling cement and liquid glass are employed when applying ‘ speckles.’ Spirit Varnish, applied and allowed to dry, is an excellent mordant for gold leaf when it is pressed down by a heated die, so as to form patterns. For this purpose blocking powders are also supplied. The powder is sprinkled over the surface to be decorated, the gold leaf laid on, and then the heated die pressed down.
Lacquers are used as a protective coating for silver, tin, and copper leaf, powders, etc. They should be transparent and may be water white or coloured. Spirit lacquers are made by dissolving ten ounces of white shellac (for colourless or blue lacquers) or orange or garnet shellac (for red and yellow lacquers) in a gallon of spirit. They dry by evaporation and rather quickly.
Ormolu is a solution of one ounce of garnet lac or white stick lac in a pint of spirit of wine coloured with a little dragon’s blood. Before using, it is diluted by adding a little weak jelly size. It is applied as a lacquer over fine gilding. For cheaper work ordinary clear size (such as parchment size or gelatine size) is used as a finishing coat; and for this purpose Glair (made by whisking one white of egg to about five ounces of water) is also used.
Black Japan of fine quality is used to protect the gilding when applied to the back of the glass.
Gilders also require specially screened and refined whiting and extra-fine china clay.
Tools and Appliances
Various tools and appliances are needed in carrying out gilding in its various branches, and we shall mention most of these, though it is not to be taken that painters and decorators will require them all.
Brushes should be of the first quality and must be kept in good condition by washing in turpentine when done with, greased with a little tallow or lard, and laid straight until again needed, when the grease is washed off in turpentine. For applying old oil size and japanners’ size, red-sable hair brushes prove the most satisfactory for both decorators and sign writers, as they can be used fiat for broad lines or brought to a fine flexible point. For running mouldings, headings, and filling large letters, etc., camel-hair swan-quill brushes or ‘ mops ‘ of fairly good size should be chosen. When laying size on broad surfaces, flat camel-hair varnish brushes will give good smooth surface and fiat hog-hair varnish brushes suitable rough surface. For enriched mouldings, and all carved work, use round hog-hair pencils. For fine work, such as coach lining, ‘ coach liners ‘ made of long brown sable hair, camel hair or fitch hair are supplied in many sizes, being mounted respectively in swan, goose, duck, crow, lark, and other quills. Size is generally applied with camel-hair mops, which are bushy and almost globular, if for fine work, or with flat camel-hair ‘ wash ‘:’ brushes for broad surfaces and glass gilding. For running lines by the help of straight line, bevelled lining fitches are used. Round badger tools or camel-hair dabbers are often preferred for removing surplus gold from the edges of finished work, though usually this is done by means of dry or slightly damp cotton wool, which is also utilised for smoothing and pressing-down purposes.
These are thin, flat brushes made of badger or camel-hair, the hairs being held in place by two thin pieces of cardboard. They are used to pick up the gold leaf from the cushion and transfer it to the work and are made in various widths, ranging from three inches to half an inch, to suit different kinds of work. At intervals the operator draws the tip over his hair or beard and from this action it acquires a certain amount of natural grease which enables the leaf to be conveyed.
Pounce Bags are made by taking small squares of coarse calico (from which all ‘ loading ‘ must be washed out), spreading part of it with a thick layer of whiting or French chalk and then tying up tightly so as to form a bag. They are used for dusting ‘ tacky ‘ surfaces before gilding, but should be used sparingly as whiting is liable to cause gold size to spread.
Skewing Bags are made of three-cornered paper, rolled so as to form a conical receptacle about half a yard wide at the mouth, and are utilised to receive the ‘ skewings ‘ or surplus gold or silver leaf as it is wiped off the work. These ‘ skewings ‘ are sold to the leaf-metal beaters.
Fine-quality sponges and wash-leathers are also needed. These, like the cotton wool, must be quite free from hard spots or specks, as they are required for smoothing and wiping down. These materials after use, like the skewings, should be sent to the beaters, who recover the gold found on them.
Gilders’ Knives have long, narrow, straight blades, like table knives. The cutting edge should not be too sharp, but must be free from notches or rust. The best quality have heavy handles, so that, being ‘ balanced,’ the blades always stand clear of board or table and remain uppermost should they fall.
Burnishers are either dogs’ teeth or agates mounted in handles, Agates are best, because they are cut in different sizes and shapes to suit various kinds of work. Sometimes burnishers are mounted on the opposite ends of camel-hair dabbers.
The Gilder’s Cushion is an important item in the outfit. It is an oblong, rectangular board, commonly measuring 9 inches by 6 inches, and is covered with tough dressed calfskin, stretched over two or three layers of thick soft flannel. Beneath are suitable straps for receiving the thumb and fingers. At one end of the board is a screen of parchment or other suitable material serving as a guard to protect the gold leaves and prevent their being blown away. The leaves as wanted are laid on the pad and cut with a knife.
Lacquer is applied by a separate set of fine, soft hog-hair or badger hair brushes. These should be washed out with methylated spirit instead of turpentine. Lacquering must be done in a warm atmosphere.
Preparation of Surfaces
Preparation before gilding must be adjusted to the nature of the surface. Painted surfaces must be quite dry and free from tackiness before applying mordant. Glossy paint and varnished surfaces show up gilding well, but they are troublesome if not perfectly dry. If there is the slightest suspicion of ‘ tackiness ‘ the surface must be pounced with the pouncing bag, or, if necessary, the surface can be covered over with weak glair.
Plaster or cement surfaces should be cleaned and then treated with jelly size laid on hot. Parian, Keene’s, or similar glossy-surfaced cement should be treated with two coats of knotting, to be followed by one of old oil gold size or japanners’ size.
Distempered walls or ceilings must be prepared by laying glair on the parts to be gilded as a priming for the oil or japanners’ gold size.
Wood, unpainted, should be dressed with glair, either applied all over or on the parts to be gilded as a background for the old oil or japanners’ gold size. The surplus glair can be easily washed off.
Stone, including marble and granite, only requires to be cleaned before applying the size. Gilding on it is not very durable unless applied to incised lettering or ornamentation.
Iron must be clean. It should then receive one or two coats of knotting, which is allowed to dry before applying the size. Old painted ironwork should either have the old paint removed before applying the gold size or be dressed with two or more coats of quick-drying paint as a ground for the size.
Paper and cardboard should receive a coating of clear parchment or gelatine size and then the mordant.
Wall hangings of the Anaglypta type may have gold size applied to painted surfaces.
Textiles, such as silk, linen, etc., must have the parts to be gilded coated with glair before applying the old oil gold size.
Glass requires no other preparation for the mordant than thorough cleaning. This applies also to French polished work, which provides a good ground for gilding.
Leather must be cleaned, damped, and dressed with parchment size if to be gilded all over, or with French spirit leather varnish (spirit varnish containing a small amount of linseed oil) for part and embossed gilding.
Wire blinds and similar articles must have the parts to be gilded first filled up by painting with ‘ coach filling,’ or with a paint compounded of paste white lead mixed with equal parts of japanners’ gold size and turpentine, worked into a thick cream. This will take the old oil or japanners’ gold size.
Setting Out the Design
Where gilding is only partial, that is to say when lines or patterns are to be covered with gold, silver, etc., the design can either be traced out with pipeclay, soft chalk, or crayon on the surface, or the design can be drawn on ‘ lining ‘ paper and then traced on to the surface. Lettering and straight lines are often traced by means of a chalked line (a soft cotton string rubbed with chalk which is held taut in the right position and then plucked up and allowed to ‘ strike ‘ out a faint white line on the surface). In some cases a ‘ pricked ‘ design is laid on the surface and traced by pouncing.
In oil gilding it is wise to pounce the surface lightly or to apply glair before the sizing. Some gilders when dealing with varnished work prefer to gild on the mat surface and then varnish round the gilding. But this gives dull results and makes varnishing difficult. Old oil gold size should flow easily, produce a thin film, drying without wrinkles and with a high gloss. If too thick it may be thinned by the addition of a little boiled oil. It should remain slightly tacky for from three to seven days. It is applied with a sable or camel-hair brush as described above, and selected as to shape and size for the special work in hand. The size should be applied thinly and smoothly, and all ragged or ‘ fat ‘ edges wiped off. The gold leaf is then laid on. In doing this it is necessary to see that each leaf should overlap the next by about the eighth of an inch and should thoroughly cover the pattern. The leaf is then carefully pressed down with a cotton-wool pad, wash-leather, or camel-hair dabber to secure a smooth surface and close adhesion. This done, the dabbing is carried on with a slight circular rubbing movement, to remove the surplus gold, which is caught in the skewing-bag. Japanners’ gilding is carried out as above, but in this case gilding must follow on quickly after the application of the size, as it dries rapidly. For the same reason the cotton-wool pad or dabber should be used promptly after laying on the leaf, first pressing firmly and then rubbing gently.
Application of the Leaf
Leaf metal can be laid on by the tip and cushion, transfer, from book , hand-laying, or ribbon methods.
In the first-named method the cushion is held in the left hand, the thumb passed through the leather loop and the fingers outstretched, the forefinger being used to hold the tip and the knife when not in use. The number of gold leaves required is removed from the book and carefully placed on the screened part of the cushion. This is best done by opening the book close over the cushion and allowing the gold leaf to fall down. As each leaf is required the end of the knife is placed under it, by which means the leaf can be lifted and gently deposited on the open part of the cushion. The art is to do this so that the leaf lies flat, any wrinkles being straightened out by gently blowing upon it. This must be done with great care, so as merely to flatten out the leaf, not to ruffle it or disturb the other leaves in the screened part. The gilder then examines the sized parts to be gilded and cuts the leaf into strips accordingly, by a gentle but firm pressure of the knife. While the gilder is naturally anxious to economise the leaf, it must be remembered that the portion of leaf cut must always be slightly larger than the part to be covered. The cut strip is conveyed to the sized part by means of the tip. This brush should be broad or narrow according to the work in hand. The tip on being taken into the right hand is lightly passed over the hair of the head or the beard, which is slightly oiled for the purpose. The slight greasiness causes the gold strip to adhere to the tip when it is pressed down upon it and the gold is then easily transferred to the sized surface, to which it at once adheres. The size has a stronger attractive force than the grease on the tip. The process is carried on as before, taking care that the strips overlap, and from time to time using the pad or dabber to press the leaf down and smooth it. If japanners’ size is used, as already stated, the pad must be used promptly after laying on the leaf.
Transfer gilding is especially useful for line work and outdoor jobs. As already explained, in this case the leaf is sent out pressed down on tissue paper. These leaves are carried on a tray or in a box slung round the neck of the gilder. Each leaf is taken in the left hand, the gold placed on the size and made to adhere by gentle pressure on the tissue paper. It is very quickly done. As a rule only the gold leaf pressed against the size actually comes off, so that the surplus can be used .and waste avoided. The pad or dabber has, of course, to be used in the usual way. As the tissue paper is semi-transparent, the gilder can see when the gold has all been properly applied.
A distinct method of transfer gilding is when printed transfers are used. In this case designs in gold and enamels are printed on transfer paper, and these are pressed on to tacky varnished surfaces. This is often resorted to in heraldic and arabesque work.
When broad surfaces have to be covered with gold, the leaves may be conveyed direct from the book to the sized surface, and for this purpose a double tip is used. Or the book can be held in one hand by the stitched edge and the paper leaf lifted slightly by the other hand, causing the gold leaf edge to touch the tacky size, and then gently sliding it upon the surface, proceeding thus with each leaf and using the pad to smooth out. These methods when applied to silver or other metal leaf are known as hand-laying, but the process is suitable only for indoor work.
Ribbon gilding is applicable to every kind of work, though particularly useful for line gilding and on outdoor jobs. As described in an earlier section, the gold leaf is made in continuous strips of different widths and wound round between two bands of paper, smooth on the outside and rough on the inside so as to hold the leaf. Silver, aluminium, and other metals are supplied in the same way. Commonly, ribbon leaf is applied by means of a gilding wheel, a handy instrument provided with a handle, for guiding, and two reels. As the wheel is run over the mordanted surface, the ribbon is unrolled and the strip of metal pressed into place; the paper which is released as a result is automatically rewound upon the second (empty) reel. This, being covered with felt, acts as a pad in applying the metal. The ribbon can also be attached to a suitable brush by means of clips, the strip being carried under the brush which presses it down. This method is especially suitable for gilding headings, mouldings, etc. Ribbon gilding can be done very rapidly and it also saves waste.
Mat and Burnish Gilding
Mat gilding is carried out on a surface previously prepared by applying three or more coats of mat gold size. Each coat must be laid on thinly and allowed to dry before the next is applied. When the last coat is dry gilding may begin. This is done by applying cold water with a flowing brush to the size, on which the gold leaf is laid from the cushion and pressed down. Not more of the size should be damped than can be at once covered with gold leaf. So it is usually a slow process, though some expert gilders manage to hasten matters thus: they cut the leaf into many strips before damping, hold the tip in the right hand between finger and thumb and brush downwards, pressed between the little finger and the palm. By this means the damping and laying on the gold is almost a continuous process. In superior work of this kind the gold is allowed to dry, is then polished with a pad of cotton wool, a coat of mat gold size applied which is damped with weak clear size, and a second coating of gold applied.
Burnish gilding is carried out on mordanted surfaces as for mat gilding, but with a little blacklead added to the composition. The gilded surface is first polished with a pad of cotton wool and the surface is then rubbed gently but briskly all over with the burnisher, a small part at a time.
Water gilding, in which the mordant (usually a gum or isinglass size) is dissolved in water, is used both for illuminating on paper and in glass gilding.
Protecting the Metal
Varnishing over gold and silver is resorted to when the decorated surface is exposed to rough wear and requires to be frequently cleaned. In such cases the metal leaf is laid on slow-drying glossy gold size when nearly hard, or directly on a varnished surface while the varnish is still tacky. After polishing or burnishing, a coat of perfectly transparent varnish is applied, preferably over the entire surface, not merely over the
Lacquering is a more effective system of protecting gold and is especially useful over varieties of metal leaf and bronze powders. Lacquer is also applied to solid metal surfaces, especially brass. The lacquer used is a compound of shellac in a volatile liquid. It is usually quite clear and either colourless or tinted. Lacquering is much more successful if the object to be treated can be warmed before the lacquer is applied in a warm room. The object treated must also be exposed to heat during the early stages of drying, otherwise the lac becomes turbid or ‘ milky.’ When relacquering old metal articles the old lacquer must be completely removed by cleaning with a solvent, washing with water and then polishing with suitable paste or powder, which must be thoroughly wiped off.
Clear cellulose lacquer should not be employed as a protective coating over leaf gilding for which an oil gold size has been used as a mordant, as the solvents in the lacquer will attack the mordant. Some of the transparent synthetic-resin varnishes should be avoided, for a similar reason. Most manufacturers of the last-named products can, however, supply a special mordant suitable for gilding work which is subsequently to be protected by a synthetic-resin varnish.
By bronzing is implied the covering of any surface with metal in the form of metallic powders, although in industrial finishing, the description is often applied to the process of imitating real bronze by means of chemical treatment. So far as the decorator is concerned, however, bronzing is carried out by two methods : the first is sometimes known as ‘ Powder Bronzing,’ and the second as ‘ Bronze Painting.’
To get good results by either method some care should be devoted to the choice of a suitable metallic powder. This varies in quality, colour, and particle size, the latter ranging from coarse, which gives a granular texture, to very fine, which provides a smoother finish. The finest grade is that known as ‘ lining ‘ quality.
The ground on which this is done should be clean, free from grease, hard, and with little or no porosity. It should first be coated with japanners’ gold size, which should be left until it arrives at a suitable stage of tackiness, which may be defined as one which has a distinct ‘ cling ‘ without being sticky. The powder is then dusted on with a pad of cotton wool or velvet, a hare’s foot or soft mop. When the whole surface is covered in this way, it is burnished with a wad of cotton wool. This finish will, however, soon lose its lustre and will tarnish if exposed for long to the air, owing to the oxidisation of the metal ; it must consequently be protected with a coat of lacquer or clear varnish.
This involves the use of bronze powder stirred into a suitable medium and applied in the form of paint. The choice of media must depend primarily on the nature of the work, but may include spirit varnish, such as shellac varnish, japanners’ gold size, and certain types of synthetic resin and cellulose varnishes; not all the latter, however, are suitable for the purpose.
After application, when the paint has dried, it must have a protective coating to prevent tarnishing. This may be a clear or tinted transparent lacquer or varnish, but, here again, care is necessary in selecting the material, and it is best to consult the manufacturer on this point.
Bronzing is extensively employed on shop fronts and fittings, lift interiors and similar surfaces, for which spray application is used. Such work is largely undertaken by specialists as it requires considerable skill and experience.
Gilding on Glass
Gilding on glass is often referred to as ‘ water gilding,’ though, properly speaking, the latter includes all gilding processes in which the mordant is some adhesive material soluble in water. Glass gilding differs substantially from other forms of gilding, though, like these, it demands both skill and experience to get first-class results.
The work is executed on the back of the glass, through which it is viewed, and the mordant is isinglass size. The first essential is to ensure that the surface to which the leaf is applied is scrupulously clean and perfectly free from all traces of grease.
Setting Out the Design
The design of the lettering or ornament which is to be used should be prepared, full-sized, on a sheet of thin white paper which must be accurately traced over in black ; this must be distinctly visible on the reverse side. The paper, thus treated, is fixed against the front side of the glass as a guide for the laying of the gold, being kept in place by a dab of paste applied at short intervals on the margin. There are other methods of setting out the design, as, for instance, whitewashing the glass and sketching on this with a pointed stick. This is not recommended, however, because the whited surface, when seen during the gilding, is cloudy and tends to interfere with the gilder’s judgment in the course of his work.
By far the best way of laying the gold in this type of work is by means of the tip and cushion. The leaves should be laid out on the screened part of the cushion, ready for work while the size is being prepared. The latter should be strained and applied while still warm with a camel-hair brush of convenient size (usually about 2 inches in breadth); it should be put on freely, starting at the top left-hand corner, going over first with a brush moderately well charged and then a second time, to eliminate any air bubbles.
Laying on the Leaf
Lay the brush across the top of the container of size, and, taking up the cushion, tip, and knife, lay the first leaf in position on the cushion, cut it, if necessary, and convey it with the tip to the size while this is still wet. It will be found that the size exerts an attractive influence, drawing the leaf suddenly from the tip when within about 1/2 inch from the glass. The tip must consequently be held parallel with the plane of the glass so that the leaf assumes a perfectly level position on the glass, stretching out at once to its fullest extent. If one edge is held nearer than the other, the leaf will probably huddle up or fold. Should such a mishap occur, it is better to remove the gold completely with the wash brush than to try to patch it up with fresh leaves.
The gilding is carried out in sections, working, so far as is possible, from the top to the bottom of the glass, in order to follow the natural flow of the mordant. If it were done horizontally, across the breadth of the glass, the runs of size from the upper section to the lower would dry before the leaf could be applied to the lower sections, leaving a thin film of hard size on the latter; owing to the transparency of the size, the presence of this film might easily be overlooked, but if it were not removed it would cause a cloudy appearance on the face of the gold applied later to the lower sections.
The size must not be allowed to become cold because, in that case, there is a risk of too thick a coating being left between the gold and the glass and this will detract from the brilliance of the work. On glass of any extent, such as a shop window, it is practically impossible to prevent the runs of size drying on the lower parts, and the gilder should keep handy a vessel of hot water and a camel-hair mop with which to soak off the dried film of size. The surface should then be resized and the leaf applied while the mordant is still in a wet state.
By working down the depth of the glass in short sections, it is not difficult to avoid cloudiness from this cause. A good plan is to stand the vessel of size in the container of hot water referred to above, thus keeping it warm and maintaining the clarity of the size essential to clear gilding ; the hot water should be renewed at intervals.
Should the size have been allowed to run so thin that it fails to stretch the leaf out smoothly, touch the glass immediately above the leaf with the brush charged with size which, with any luck, will pass under the leaf and spread in all directions. On laying the first leaf into position, it may be that the flow of the size will carry the leaf down a little ; it may be raised by placing the point of the tip against it and holding it there for a second or two, but care must be taken not to allow the hair of the tip to come into contact with the wet size. If this happens, the size may ciss and the tip, wetted by the size, may hold the leaf tenaciously and the gold may be destroyed.
It is an old but true maxim in gilding that cutting up wastes most gold, and so the work should be completed with as few joints as possible. In glass gilding, as in other forms of gilding, the size of the leaf applied should be slightly bigger than the area of the work it has to cover.
When the required surface has been gilded, loose gold is cleared from overlapping joints and the work burnished with a pad of cotton wool, working with a circular motion from the last leaf completed back to the first. Only very slight pressure must be exerted to avoid scratching ; this process is known as ‘ polishing.’
Next take the camel-hair mop and go over the work quickly and lightly with hot water ; this slightly re-liquefies the size between the leaf and the glass and helps to get greater uniformity.
When the work is dry, for the best results, ‘ double gilding ‘ or a second coating of gold leaf is next applied. The object of this is to make the work look more solid and avoid any possible shadiness which may have occurred. Fresh size is applied lightly over the areas to be gilded. Pass the brush once only over the part to be gilded, without allowing the size to flow, as in the first coat, but damping not more than enough for one or two leaves at a time. Too flowing a coat may have the effect of softening the size under the first coat and should be avoided.
For cheaper work, the second coat of gold leaf is omitted and the process known as ‘ faulting ‘ carried out instead. This consists simply in laying on patches to cover holes, faults, and thin places, and is not very satisfactory since the patches are apt to show up more brightly than the remainder.
After the second coat of leaf has been polished in the same way in which the first coat was treated, or after faulting has been carried out, the next stage is trimming, by which is meant the removal of superfluous gold so as to leave clean edges. The trimmer is chisel-shaped and is often cut by the gilder himself from a wooden pen-holder or meat skewer. The trimming is usually done after the first coat has been polished, before either second-coating or faulting, because the design on the paper on the face of the glass can clearly be seen through one coat of gold.
The use of the trimmer requires a little practice. It is employed freehand in conjunction with a straight-edge, for dealing with straight lines, and a mahl-stick is a useful adjunct. The straight-edge should have small pads of rubber or cork glued under each end to keep it not more than 1/2 inchfrom the surface. The trimmer is kept moistened with water to facilitate the removal of the surplus leaf. As it tends to become blunt with wear, it should be resharpened periodically.
When the work has been trimmed, it should be fixed by applying a coat of gold size, covering the gold and overlapping on to the glass for about J* inch beyond the edges. When this is dry, add a little red lead to black japan and paint over the body of the work, within the outlines. The paint should be put on close up to the edges of the gold but without overlapping on to the glass. Allow this coat to harden, and if any superfluous gold remains, clean off by soaking with warm water and rubbing with a pad of moist cotton wool. Finish with cold water and a leather and the work’will be complete.
An alternative process is to apply the black-japan mixture directly on to the second coating of leaf, without using the trimming chisel. The backing-up paint must be very carefully applied to conform with the outlines of the design, giving clean edges. A sable pencil of convenient size should be employed for the purpose. If this system is adopted, some gilders, in order to ensure accuracy, take this precaution: after the second coating or faulting has been completed, they remove the paper with the design from the face of the glass and make a pounce by pricking the outlines of the lettering or ornament with a needle at intervals of about 1/2 inch. They then fix the paper, by means of small pieces of adhesive tape or paper, on the gilded sides of the glass, so that guide marks, made in advance, on the face of the glass and the paper itself, exactly correspond, after which they pounce the design with lampblack.
When the backing coat, applied in this way, is dry, the surplus gold is removed with cotton wool and water and the edges sealed with a coat of varnish.
Peeling of Water-gilded Work
Trouble is often experienced with gilded work peeling from shop windows, glass signs, etc. This, in most cases, is due to condensation, caused by poor ventilation. If condensed moisture is continually deposited on the work, it will sooner or later break down the gold size (or varnish, which is sometimes used in place of gold size) which seals the edges and finds its way to the mordant. This, being water soluble, soon loses its bond, which is further weakened by the contraction and expansion of the glass, resulting from changes of temperature.
It is not usually within the power of the gilder or decorator to improve the ventilation of such interiors, because to do so effectively involves structural alterations outside the scope of his work. If condensation cannot be prevented, the most he can do is to reinforce the backing with a coat of water-resisting varnish – boat or yacht varnish is the best for the purpose – running this very slightly on to the glass, to repel moisture attack as efficiently as possible.
Gilding Stucco or Gesso Work
For decorative purposes the surfaces may be covered over with stucco, gesso, or other composition, which can be modelled or stamped with any designed desired and, when dry, sized and gilded. If the design is deeply carved or incised or embossed the gilding will have to be carried out with particular care. It will be necessary to see that the leaf metal more than covers the surface and is gently but firmly pressed down so as to cover but not obliterate the decoration. In this kind of work hot dies are also used, and occasionally certain parts, raised parts or sunk depressions, may be ‘jewelled ‘ by being silvered on gold, or gilt on silver, or painted with brilliant enamel colours. The effect is greatly enhanced if the gilding is treated differently in parts, portions being mat, others burnished, and the whole lacquered, but leaving the mat gold untouched, as the aim is to produce strong contrasts.