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Gilding.
Gilding is a term that applies not only to the fixing of gold leaf but also
to the fixing of all other leaf or powdered metals to the surface of wood,
paper, stucco, glass, metals, textiles, etc. It also covers bronzing and
lacquering.
Materials.
Gold Leaf.
Gold is available in the form of leaf and powder. Gold leaf is made by rolling
thin sheets of pure gold, alloyed with a small amount of silver, copper or
other metal, in presses and placing the thin sheets between vellum sheets,
and finally gold beaters' skin, and flattening them out with hammers. The
hammering is carried out until the gold leaves are about 1/300,000 of an
inch thick. These leaves are cut into squares(of around 10 square inches)
and laid between the pages of small books, the pages of which are powdered
to prevent sticking. Each book contains 25 leaves. The gold should assay
at about 22 carats.
Color variation is mainly controlled by the kind and amount of alloy used.
Also the color of gold differs according to origin. The range of color is
from red, orange, extra deep, medium, deep, pale,citron, green, lemon and
white. Lemon and white are worth less than red and orange.
Special gold leaf, for applying to exposed ironwork etc., is supplied in
leaf about double the normal thickness.
For very delicate work extra-fine leaf is supplied in very pure gold not
less than 23 carats. This is the most expensive.
Gold leaf for gilding glass is put in books without powdered pages and require
careful handling and storage as they are easily ruined by dampness etc, causing
all the leaf to stick together.
Transferred gold is usually preferred as the gold leaf is pressed
against white tissue paper which it adheres to until pressed
against
a more adhesive surface.
Ribbon gold is gold leaf cut in thin strips and transfer-pressed on
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 from leaf gold; it is commonly supplied in
the form of gold tablet or illuminating gold, the powder being
mixed with weak gum water in moulds; or formerly as shell gold, the
powder and gum water being dried in mussel or other shells.
Gold substitutes. There are various alloys used to imitate gold; copper
and tin; copper and aluminium; copper and zinc(Dutch metal) being one of
the most common. All gold substitutes need to be protected by a coat of lacquer
to keep their lustre and prevent tarnishing.
Gold paint and liquid gold are bronze powders held in suspension in
a suitable liquid medium. They need to be protected with a coat of lacquer
or will soon tarnish on exposure to air.
Trade secret. You can make a suitable lacquer by whisking
the white of one large egg in about five ounces of water.
Mordants.
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 tackinesswhich can only be determined by experimentit
should be transferred to a closed vessel, adding a small quantity of litharge
(1oz. 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 color 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. Water Sizes.
Islnglass Size.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.
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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. |
Tools and Appliances.
Various tools and appliances are needed to carry out gilding in its different
branches. The standard equipment is listed below and should be adequate for
the majority of circumstances.
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 flat for broad lines or brought to a fine flexible point.
For running mouldings, beadings, and filling large letters, etc., cam el-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 flat 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.
Gilders Tips.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
to 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.
SkewingBags 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 Gilders 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, Keenes, 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
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.
Hand-laying
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
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
beadings, 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 gold.
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.
Bronzing
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. BSo 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. bThe finest grade is that known
as lining quality.
Powder Bronzing.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 hares 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.
Bronze Painting.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.B 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 was formally 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 gilders 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 ~ 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.
Polishing.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.
Double Gilding.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.
Faulting.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.
Trimming.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 (as used by sign writers for the purpose of steadying the hand)
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 ~ inch from 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.
Fixing.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 ~ 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.
Alternative Process.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 ~ 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
varnishboat or yacht varnish is the best for the purposerunning
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.
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