A mirror is an object that reflects back an image without losing much of the image quality. There are a number of different types of mirrors, but the most common mirror is a plane mirror. This type of mirror has a flat surface and is designed to reflect visible light. Mirrors are used for self-grooming, architecture and decoration. High quality mirrors are also used in a variety of scientific equipment, such as telescopes and microscopes.
How are mirrors made?
Prior to the use of glass and silver, highly reflective surfaces were created by polishing cut obsidian rocks (volcanic glass). This took a lot of time and effort and the reflective properties weren’t anywhere as good as modern mirrors. Mirrors today are made by applying a highly reflective coating, such as silver or aluminum, to a substrate such as glass. Glass is used in mirror production because of its clarity, it adaptability, its rigidity and its ability to take a smooth finish. The reflective coating is adhered to the backside of the glass which protects the coating from damage.
The process of adhering the coating to the glass follows a number of steps. First the glass is cut to size, and it is shaped and polished. It is also cleaned to make sure that the coating will stick without creating bubbles or scratches. After this has occurred the glass is coated with tin oxide. This is done because silver or aluminum will not adhere straight to glass and the tin oxide gives the coating something to bond to. The silver or aluminum is then sprayed onto the glass over the coating of tin oxide. The coating is then allowed to harden. Once the silver or aluminum coating is hard a wash of copper is applied to protect the reflective coating and give it durability. The reflective coating is then spray painted with a protective layer of paint. This usually a blue-gray color such as you would normally see on the back of any plane mirror. The mirror is then inspected, cut to size and packed for shipping.
The following is a video of a mirror being manufactured in a large factory: