have been in use for thousands of years. Polished brass
“looking-glasses” are mentioned in biblical text and mirrors made of
polished bronze were known to ancient Egyptians,
Romans and Greeks.
mirrors can be traced to the 3rd century A.D. when gold leaf was
attached to the back side of a piece of glass. Relatively good glass mirrors were produced
from the 12th century in Venice by placing a polished
metal plate behind
a sheet of clear glass.
By the 16th
process had been developed to apply a thin amalgam of tin and mercury
the back side
of a sheet of
glass to produce a much improved mirror. This
principle process used for mirror
production for several hundred years until around 1835. In that year a process for
treating glass with a thin layer of silver was perfected by Justus von Liebig. The silver technique produced a mirror with significantly
clarity and brightness than the
tin/mercury mirror and
quickly displaced the older process.
Glass, and mirrors
were still relatively rare in late colonial America. As a result, it
became common practice in the late 1700's and early 1800's to install
a large mirror in the door of wooden works shelf clocks. This
increased both the value and utility of the clock which, hopefully,
Clocks produced prior to 1835 would, of course, have used mirrors
produced using the older tin/mercury process. These early
mirrors are clearly distinguishable from later silver process mirrors
in that they have a softened patina that reflects light more subtly than
silvered or modern mirrors.
Due to the inherent dangers of handling mercury, it is very unlikely
that a source for creating an original tin/mercury mirror will be
found. To create or restore one of these early tin/mercury mirrors, an
technique known as Eglomise can be used. Eglomisé is the process of
applying gold or silver leaf to the reverse side of a glass object.
Applying silver leaf produces the soft reflective surface seen on original tin/mercury mirrors.
The following presentation covers the application of silver leaf to a
glass in order to create or repair an early tin/mercury mirror.
There are many different techniques that can be used to apply leaf to
glass. Web sites such as
Plus have some lively discussions about techniques for gilding on
Martha Stewart has a good presentation on her web site for using the Eglomise
technique to create a mirror.
Well known NAWCC member Lee Davis has, for many years, taught a highly
regarded course on reverse glass techniques including eglomise.
The technique presented here is only one of the many possible. It was
chosen because it can be quickly perfected by a restorer without
previous gilding experience and it doesn't require the
purchase of a lot of special tools that may go unused for long
Gilding on glass is a
skill that the average clock restorer can master. It does, however,
require some practice to master the techniques. Please read this
entire presentation before attempting a project. It is strongly
recommended that a small "practice" glass be used to work out the
finer points before attempting a full sized project.
The materials needed for creating a mirror are:
1. An appropriately sized piece of antique (wavy) glass.
2. One or more "books" of silver leaf.
3. A package of gelatin capsules.
4. A bottle of distilled water.
5. Alcohol (denatured or isopropyl)
The tools needed include:
1. A pan large enough to allow the glass to rest in it.
2. A new one-inch, soft bristled paint brush.
3. Wooden blocks to brace the glass on an angle.
4. A roll of waxed paper
5. A soft felt cloth.
6. A can of Bon Ami cleanser.
8. Cotton balls.
Cleaning the Glass: The
glass must be very clean to receive and hold the gilding. Use Bon Ami
and a sponge or rag to scrub both sides of the glass to remove any
foreign material, body oils, etc.
Dry the glass carefully
with lint free rags then wipe both sides with acetone.
cleaned glass carefully in good lighting. Scratches in the glass will
be even more visible once the silver is applied. If there are small
scratches, make sure they are on the un-silvered side of the glass.
Place the cleaned
glass between paper towels until needed.
Size is the adhesive
used to attach the leaf to the glass. For this project the size is
made from distilled water and gelatin capsules.
Gelatin size offers
several advantages over other types of adhesive.
dries crystal clear.
It shrinks when it dries which helps to remove wrinkles.
capsules can be purchased from health food stores such as Hi Health
and some pharmacies. Food gelatin powder can also be used, but clear
capsules dissolve quickly and dry crystal clear.
Overly strong size will dry cloudy and become worse with age.
- Weak size will lift and bubble when the second gild is applied.
- Gelatin glues break down with over-heating or boiling.
- Poor quality water will cause cloudiness in the size.
Mixing the Size: The
normal recipe for sizing used for leafing on glass is one #0 capsule
to one cup of distilled water.
Pour about 1/4
cup of distilled water into a clean glass measuring cup.
Remove the halves of one capsule from one another and place in the
Allow the capsule to soften for a few minutes then use a spoon to
agitate the water until the capsule pieces are totally dissolved.
In a second cup,
heat about 1 cup of distilled water to a hot, but not boiling state.
Pour enough of
the warm water into the glass measuring cup to make up the total
one-cup volume. Add about 1/2 tea spoon of alcohol to make the water
less "clingy". Stir and allow to stand.
Note: It is not
necessary to keep the sizing mixture warmed. It can be used at room
Silver Leaf: As with
most products, there is a wide variety of silver leaf products. The
most common product is an imitation leaf such as Mona Lisa. This is an
inexpensive leaf material made from alloys of aluminum and copper. Imitation
leaf can be used for creating a mirror.
It is a thicker
material than real silver leaf which makes it somewhat easier to
handle. It tends to be slightly less reflective than
real silver and may retain more wrinkles.
It is, however,
an excellent material for developing you skills and techniques and,
depending on the application, may be a good choice.
Real silver leaf is
somewhat more expensive than imitation but usually provides a very
authentic looking mirror. Monarch offers a real silver leaf at a price
very competitive with imitation leaf. It is available from a number of
on line suppliers including
Wehrung and Billmeier
Domestic Silver is a very high quality silver leaf with purity greater
than Sterling. It is available on line from
Dick Blick Art Supply
This is a more expensive product but produces a very realistic mirror.
Transfer Leaf: Gold and
silver leaf are usually provided in one of two forms. When a book of
leaf is referred to as "loose leaf" it means that each leaf is placed
between two sheets of tissue in the book. There are usually 25 leaves
Transfer leaf is the term
used when each leaf is attached to a sheet of tissue or backing paper.
Transfer leaf is most often used when working outside where the
slightest breeze would easily blow a loose leaf away.
A form of
transfer leaf is used in this process because it allows an
easier to master technique than simply lifting a loose leaf with a
gilder's tip and dropping it on the glass.
Transfer leaf is
easily made from a book of loose leaf by first cutting squares of
waxed paper to a size slightly larger than a leaf.
Open the book to expose
a leaf then lower a piece of the waxed paper onto the leaf. Rub gently
with a finger and the leaf will adhere to the waxed paper. Gentle
rubbing will also remove most of the wrinkles.
Cut a supply of
waxed paper squares but don't put a leaf on a sheet until you are
ready to lift it and apply it to the glass.
With the size made up, the waxed paper sheets cut
and the glass cleaned, the application of leaf to the glass
Place a suitable block in
the drip pan to allow the glass to be positioned on a slant. It helps
to place some tape (that has been doubled over ) on the blocks so that
the glass stays in position.
Place the cup of size
in a convenient position, but well away from the book of leaf. Spills
will cause leaf to stick to the tissue and be ruined.
Size can be brushed
onto the glass or simply poured. The excess size will run off of the
glass into the drip pan.
Place a piece of waxed
paper on a leaf, rub with a finger to get it to stick. Take your time
and ensure that all of the leaf is being held by the waxed paper. A
loose edge might fold over when lifted.
Carefully position the
leaf and waxed paper over the glass and slowly lower into contact.
Hold the edge of the
wax paper and gently rub the waxed paper to press the leaf into the
glass and "squeege" excess size from the glass.
Work from the
center outward to remove wrinkles and size. Do not become over
aggressive or the leaf may tear.
Very gently lift
the waxed paper and discard.
It is not
necessary to get the leaf perfectly wrinkle free. That will be done
with the felt rag once the size has set up.
If tears do develop in the
leaf, don't worry. This will be deal with in later steps.
Apply a second leaf,
overlapping the first by about 1/8 inch. If necessary, use a soft
brush to apply more size to the glass.
Be careful about
disturbing the first leaf.
Continue applying leaf
and size (as needed) until the glass is completed covered with leaf.
If there are
holes in the coverage, use a small brush to apply size. Use partial
pieces of leaf to cover the holes. Small pieces of waxed paper can be
used to press the leaf down.
Allow the size to
cure for several hours or over night.
Once the size has
cured, place the glass on a padded surface such as a towel with the
gilding facing upward.
Wrap the felt rag over a
finger and (beginning in the center of of the glass) gently burnish
the silver with the rag. Go slowly and use light pressure.
You will actually
be able to see the silver become smoother and small wrinkles will
disappear. Continue working
from the center outward until most of the wrinkles are removed.
You may remove
some leaf with the rubbing. It will be covered with the second gild.
Lift the glass
and view from the front side. The image should now be noticeably
brighter and clearer.
Second Gild: It is
usual to apply a second layer of leaf to the entire glass. This will
cover any small "holidays" and actually produce a brighter image.
The sizing can be
made to only 1/2 the strength used for the initial gild. That is one
capsule to 2 cups of water. Again, add 1/2 tea spoon of alcohol to
make the size flow.
Use a soft brush
to apply size to the glass and apply leaf exactly as before.
Usually, the shape of
the glass will be such that it is not exactly multiples of the height
and width of the leaf. It is perfectly acceptable to cut leaf to odd
To cut leaf without
tearing, place it between two tissues from the book then lay a
stainless steel ruler across the line of cut. If the ruler has a cork
backing, turn the ruler over so that it rest tightly against the
Use a new hobby
knife blade to cut through the two tissues and the leaf.
Once the piece as again
cured over night, use the felt to burnish and brighten the silver.
The mirror is now
competed except for application of a protective backing paint. The
luster of the silver should be very similar to that of an original
If a brighter
mirror is desired, some craftspeople carefully pour hot (almost
boiling) water onto the front (un gilded) side of the glass. Care must
be taken to avoid burns and the water should not be allowed to touch
the back side of the glass. This technique will usually produce a
noticeable brightening of the mirror image.
Backing: Some type of backing must be applied to the silver to provide
protection and prevent oxidation of the leaf. A dark water-based
acrylic paint works well for this. Asphaltum can also be applied to
the back of the glass for an authentic look and feel.
The finished mirror will
show very well and looks much more like the tin/mercury originals than
modern or even re-silvered mirrors.
This restoration technique
takes a delicate hand and some practice, but is well within the skills
of the average restorer. A few practice
pieces are usually all that are needed to master this very useful
If you decide to
give it a try, take some photos of the finished piece and pass them