--
a short history of mirror production

the first mirrors
were likely to be a pool of water where one could observe
their reflection. ancient and primitive mirrors were typically
made of polished stone (obsidian in stone age turkey,
and pre-columbian peru), perhaps wetted to make them more
reflective.

egypt copper mirrors
long before man was able to make mirrors out of glass,
mirrors made of metal (copper, bronze, silver, tin, etc.) were
used. sheets of metal were flattend and polished until it could
be used as a mirror. rounded forms, disks, sometimes with
a design on the back, and usually with a handle.

roman glass mirrors
following pliny, natural history, glass mirrors were invented
at sidon in the first century AD.
surviving examples date earliest to the second century AD.
after the discovery of glass making, the romans made mirrors
out of glass by finishing them with a metall layer.
in roman graves dating from the second and third century
there were also found pieces of glass covered with lead.

middle ages
after the discovery of glassblowing in the 14th century,
mirrors were made out of glass bulbs.
after cooling the bulbs, they were cut in pieces, thus forming
little hollow (convex) mirrors.
(although these mirrors did not have a perfect reflection,
people did not mind at all.
the mirrors available previous at that time, were made out of
metall which wasn't flat and had an even worse reflection).

renaissance mercury mirror
a method of backing a plate of flat glass with a thin
sheet of reflecting metal (tin/mercury amalgam -
the reflecting layer of mercury on mirrors existed out of
75% of tin and approximatly 25% mercury. )
came into widespread production on the italian island of
murano, near venice during the 16th century.
the mirror-makers perfected a method of backing larger
sheets of glass. in the first act of industrial espionage,
the french under louis XIV bribed murano experts to come
to paris. after apparent threats and poisonings, they returned
to italy, but by then it was too late, and the hall of mirrors
at versailles was one result.
also in germany and in belgium this method was already
being used. the exact ingredients and procedure were kept
secret for a long time.
producing a mirror was a complicated and delicate process,
therefor these mirrors were very expensive.
from then on, mirrors got bigger, cheaper, and more pervasive.
on top of that, the production was very unhealthy, due to the
fact that mercury fumes are very toxic.

19th century silver mirror
the chemical process of coating a glass surface with metallic
silver was discovered in the 19th century.
this advance inaugurated the modern techniques of mirror making.
the technique is said to be invented by the german justus von
liebig in 1835.

present-day mirrors
are made by sputtering a thin layer of molten aluminum or silver
onto the back of a plate of glass in a vacuum.

--
reflection

why does the mirror reverse left to right and not top
to bottom?
the mathematical or geometrical version of the question is:
‘why does a chiral object (such as a right hand or glove) appear
as an object of opposite chirality (left hand or glove) in the mirror?’
the answer is that chirality of the three-dimensional space is
dictated by the choice of the directions of the three axes.
when the direction of one axis is reversed, as is the case in a
mirror image, the chirality of space changes to the opposite one.
if two mirrors are set side by side (with, say, a 90° angle
between them), the axes in the doubly reflected image are
inverted twice and the handedness of the image is not changed.
in such a double mirror, a right hand looks like a right hand.
this set-up lets you see how you really look, but most people find
it very difficult at first to use a mirror like this for shaving.

--
common uses

whether hand-held, wall-mounted, or standing, most mirrors
have been placed in frames. mirrors are used
- for inspecting parts of one's body which
are difficult or impossible to see directly, such as the
face, neck or the whole body.
- for self-contemplation.
- rear-view mirrors are applied in and on vehicles (such as
cars, or bicycles), to allow drivers to see other vehicles
coming up behind them.
- rounded (convex) mirrors are sometimes placed at road
junctions, and corners of places such as parking lots
allowing people to see around corners to avoid crashing
into other vehicles.
- mirrors are also sometimes used as part of security systems,
so that a single video camera can show more than one
angle at a time.
- interior decoration to create an illusion of space
- the use of mirrors for 'cutting' and snorting cocaine.
- the classic 'mirror on the ceiling' for use during sex ...
(the story of hostius quadra, a roman who had a giant
metallic concave mirror in which his orgies were magnified.)
- telescopes and other precision instruments use front
silvered or first surface mirrors, where the reflecting
surface is placed on the front (or first) surface of the
glass, in order to eliminate faint reflections from the
glass itself (which gives better image quality).
modern thermonuclear weapons use x-ray mirrors...





---
see page 2

humans and mirrors

---
see page 3

anamorphic art mirrors