Mirror making dates back thousands of years. Throughout history, mirrors have been made using various materials for several purposes. From their origin to now, mirrors have come a long way in quality and concept.
Obsidian Stone is a natural glass which is produced by active volcanoes. The earliest known use of obsidian dates back 700,000 years to Kenya, where it was used in pottery and arrowheads.
The earliest known use of mirrors dates back to 8,000 BC, and was constructed from obsidian stone. People of this time would polish this stone heavily, which resulted in a great reflection of the glass- making a mirror!
Over the years, obsidian mirrors become increasingly associated with black magic, and are now commonly known as a scrying mirror or “black mirror”.
The mythology of the black mirror is thick with superstitions and magic. One black mirror ritual states that young women who look into the mirror in a dark room can catch a glimpse of their future husband’s face in the mirror, or a skull which signifies that their fate was to die before getting married. Talk about spooky!
The problem with these mirrors is that they were super heavy, so they weren’t normally made very large. They were mostly used for small decoration by the rich unless you were very wealthy, like royalty wealthy. This can be seen in Egypt, specifically with the Lighthouse of Alexandria in 280 BC.
Lighthouse of Alexandria
This lighthouse had a large curved mirror at its center. During the day, this mirror reflected the sun. However, at night, it was actually used to help fishermen! The mirror reflected fire into a beam, and this beam could be seen up to 100 miles away by those at sea. This ensured that those at sea could make it home safely.
This is a great example of wealth being used for good! On the other hand, there are rumors that they also used this lighthouse to try and set their enemies boats on fire- but we’ll save that for another blog post.
Mercury Coated Glass Mirrors
Fast forward to the 16th century, Italians started using glass plates to make their mirrors. Enter in a somewhat controversial substance- mercury. In the present day, we know mercury isn’t something that should be widely used, as it is toxic and can result in death!
However, 16th century Italians did not know this- but what they did know is that when a mercury coating is applied to glass, it creates a beautiful reflection. I’m glad mirrors are no longer made this way!
Italians at this time were seen as the superior mirror makers and kept their mirror making process secretive. They would even go as far to spy on their fellow mirror sellers and assassinate anyone who tried to sell their secret to foreigners!
Silver Coated Glass Mirrors
In 1835, Justus Von Leibig created, what we would consider, the modern day mirror. He traded in the italian mercury for silver, and created the silvering process on glass plates.
Glass is a good sturdy material that can be smoothed down. It’s not very reflective, so that’s why a silver coating is applied. This coating is applied after silver is boiled down. This liquid silver is then applied in a thin, even coating to the glass. Another method is to spray the liquid silver onto the glass.
Once these mirrors are initially made,they are covered with a protective coating and then polished. Polishing mirrors perfectly is essential. If this is not done well, the mirror will create waves- which will leave the mirror unusable, as it creates distortion.
Aluminum Coated Glass Mirrors
Another modern day technique that is used is to heat aluminum and apply to glass via a vacuum. The aluminum bonds directly to the cooled glass. Unlike silver, aluminum will not tarnish. It also has an amazing level of reflection. This level is the highest of any metal in the ultraviolet and infrared spectral ranges. That’s quite the reflection on reflection!
Front Surface Mirrors
For science & engineering, a precise reflection is required. Optical mirrors, also known as front surface or first surface mirrors, are coated in a multi layer automatic coater. With a standard mirror, the reflection is from the back side, whereas with a first surface mirror the coating is on the face of the glass.
As a result, it has no double image, giving a true reflection. After the aluminum layer is applied, a dielectric layer is added to prevent oxidation & scratching and further enhance the reflection for specific wavelengths. Once this is done, a laminate layer is applied as protection during the shipping process.
This mirror has the highest quality control provided, ensuring that the mirror is flawless. First surface mirrors can be used for engineering and science applications such as robotics and laser projects.
And that is the history of how mirrors are made! From past to present, mirrors have held an important role in society. Originally used by the rich as a status symbol, moved to a secret held by the Italians, to now- where we use mirrors for everything from laser technology to news teleprompters.
The mirror making process has transformed from the dark volcanic glass obsidian, to the toxic mercury coating, to now- where we use silvering process on glass.
Thanks for coming on this history ride with me, mirror contisures!