The Art and Science of Mirror Production

When most people use the term "mirror," they are referring to what is known as a plane mirror. This object takes the light that hits it and reflects it back. Those used for common consumer purposes are of this sort.

A mirror is essentially a highly reflective surface. The type that people see on walls or in bathrooms are known as back-silvered mirrors. This means that the reflective surface — in most modern ones, this is aluminum — is viewed through a thin layer of glass. The glass protects the aluminum from scratching and bubbling, but also distorts the image somewhat.

Early mirrors were created by simply polishing a suitable substance until it became highly reflective. Examples from the Neolithic era have been discovered, made by grinding down obsidian rocks and polishing them to an incredible sheen. They have remarkable properties, allowing even subtle details to be clearly seen in their reflections.

To make such a device, a person first needs to find the right stone: obsidian, ideally. A rougher stone is used to grind the base stone down to a flat surface on one side. After this is achieved, a finer grinding stone and clay slip can be used to polish the stone to a fully reflective sheen. Extremely fine abrasives, such as ash, can help further. After a substantial amount of time and effort, the person will have created a very primitive form of mirror.

Modern ones are made using an entirely different process. Allowing liquid metals to condense on a sheet of glass can provide a surface far more reflective than anything achieved by polish. This can be done at home with only a few supplies easily acquired at a local chemistry shop.

With pure silver nitrate, distilled water, and ammonia, a person can make a mirror virtually indistinguishable from those purchased at a store. The process (in abbreviated form) involves dissolving a small amount of silver nitrate in distilled water, then adding diluted ammonia until the mixture goes through distinct chemical changes. A second mixture is made using silver nitrate and Rochelle salts. This mixture must be boiled and filtered. By pouring these mixtures on to a very clean piece of glass sufficiently heated to the proper temperature, the silver will precipitate and form an even coating on the glass. After drying, the back of the silver can be coated with a solid paint to help prevent degradation of the silver.

Commercial mirrors are manufactured in more or less this same manner, though materials such as aluminum might be used instead of silver. Ones made for specialized purposes, such as those to be used in lasers or telescopes, are manufactured using much more exacting techniques to achieve much greater precision, but the general principles remain the same.

About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Link to Sources

• https://www.scientificamerican.com/article/bring-science-home-candle-mirror/#:~:text=Most%20mirrors%
• https://www.explainthatstuff.com/howmirrorswork.html
• https://www.madehow.com/Volume-1/Mirror.html

See our Editorial Process Share Feedback

Editors' Picks

Discussion Comments

By anon307341 — On Dec 04, 2012

What do I use to remove some of the back of a mirror to put a picture there?

By anon232900 — On Dec 03, 2011

@anon139478: It would look like a mirror without lights between the two mirrors. If you want to see what it looks like though, look up "infinity mirror." It's a two way mirror against a mirror with LEDs between the two.

By anon139478 — On Jan 04, 2011

if you were to stand behind a two way mirror and observe a mirror on the other side, what would it look like?

By anon126272 — On Nov 12, 2010

Just want to know where does the mirror or glass come from? thanks!

By anon58207 — On Dec 30, 2009

For a simple repair around the edge of a bathroom mirror, can one apply a bit of silver nitrate to take away the dark spots?

By anon51701 — On Nov 08, 2009

This is a really interesting and informative article. I run a business selling mirrors on the internet and often get asked by customers if there is a way to repair the reflective coating on the back of their old mirrors when it has corroded with age.

To my knowledge the only way is to remove the entire reflective coating and refinish with a new silver coating, which I have found to be too expensive for everyday wall mirrors. Are you aware of any techniques or products that can be used to repair small areas of corrosion on glass mirrors? If there is such a product I would love to sell it. Many thanks, Tim

By anon42611 — On Aug 22, 2009

we have two dining room mirrors, very solid and fairly heavy, custom designed. We have always had a glass/mirror company hang them. They are each 4 ft. wide and approx 5 feet long. The "hanger" technician hung them using a wire cable in the back and a hook supported by a haeavy wood nail into the stud. There are no wood blocks at the bottom, so the mirror is not exactly parallel to the wall. Is this correct?

By anon20475 — On Oct 31, 2008

I want to try to make my own mirror. Can you be more specific about the technique you described in terms of quantities and/or concentrations. Is silver nitrate expensive?

By dorothy — On Jul 25, 2008

Is there a difference in mirror quality and which way is better to install a large wall to wall mirror? Here's some background for my questions. I have 3 bathrooms each with very large wall to wall mirrors over the sinks. All three have been up over 15 years and look as good as the day they were installed. Now I have an additional bathroom that needs a mirror 104 x 46. The quotes I've received have range from $435 to $286. The original mirrors were all glued to the wall with a sealer at the bottom. No brackets anywhere just glued. The company with the lowest quote says they do not glue mirrors to the wall and only use brackets at the top, with 1/8 blocks at the bottom for the mirror to sit on. While trying to find which is better, gluing or bracketing, I came across a web site which said to look at the quality of a mirror. The example listed was a good quality mirror would not have a 'flat' reflection with no 'depth' to it? Is there a difference in mirror quality and what should I ask for. Thank you

By Ajax — On Jun 25, 2008

Hi. What paint product is commercially available ready for use to coat the back of a glass brick wall to make it a mirror brick wall?

I need some paint to do this to make the wall reflective because the glass brick will no longer have light at the back, due to a new brick wall being built behind it. The simpler the process the better? I need something really ready to use off the shelf, without learning new chemistry. Thanks and kind regards, Ajax

By anon6300 — On Dec 23, 2007

The information given, was just what I was looking for. A brief, but accurate description of how mirrors are made and tidbits of other related facts.

Thank you!

By ronaldgordon — On Jun 24, 2007

Dear wiseGEEK,

I enjoyed this article and it reminded me of my friend who's Father's Business was a fine glass business. The name of this business was "J.G. Budd Glassware". Their merchandise included fine glass tables, framed wall mirrors, mirrored glass tile, and very large size glass mirrors for homes and estates. I spent many years of my life with my friend and loved his family very much. They will be remembered in my prayers.

Thank You,

Ronald Gordon